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Review

Squalene from Silphium perfoliatum: A Novel Source with Long-Term Stability and Applicability in Topical Formulations

by
Arielle Springer
1,
Claudia Gras
2 and
Willi Moor
2,*
1
Freelance Scientific Consultant, 85402 Kranzberg, Germany
2
DOEHLER GmbH, Riedstrasse 7-9, 64295 Darmstadt, Germany
*
Author to whom correspondence should be addressed.
Cosmetics 2026, 13(3), 148; https://doi.org/10.3390/cosmetics13030148
Submission received: 11 April 2026 / Revised: 26 May 2026 / Accepted: 5 June 2026 / Published: 9 June 2026
(This article belongs to the Section Cosmetic Formulations)
Browse Figure
Versions Notes

Abstract

Background: Squalene is a key sebum lipid that plays an important role in skin barrier function, suppleness, and antioxidant protection. Age-related or disease-associated reductions in squalene levels—for example, in atopic dermatitis—reduce skin resilience and increase susceptibility to environmental stressors. However, its oxidation products can have inflammatory, comedogenic, and pro-aging effects on the skin, which is why adequate stabilization is essential when used in topical formulations. Objective: Therefore, identifying sustainable sources of stable squalene with beneficial skin-care properties is of considerable interest. Methods: This review employed an application-focused literature search and comparative analysis of established and new squalene sources, evaluating chemical composition, manufacturing processes, stability, and biological effects following topical applications based on predefined analytical criteria across peer-reviewed studies. Results: Silphium oil appears to be a promising novel source of highly concentrated, sustainable, and stable squalene with potential skin-conditioning properties at concentrations typically used in cosmetic products (2.1–12.6%) while preliminary formulation tests indicate emulsifiability even at concentrations up to 15%. It contains over 3% squalene, a fatty acid profile with over 66% PUFA, and negligible levels of oxidation byproducts (hexanal < 3 ppm) even after years of storage in various types of packaging. Although independent validation and broader comparative studies are limited, these results reveal new possibilities for the use of previously underutilized plant sources in skin care applications.

1. Introduction

Squalene plays a central role in skin physiology: As a major component of human sebum (approximately 13%), it contributes substantially not only to skin lubrication and barrier function, but also to the antioxidant system. The isoprenoid structure with its numerous unsaturated carbon bonds protects cells from free radicals [1]. Even though its antioxidant effect is limited and depends on numerous other factors, squalene has been described as a primary oxidation scavenger in the skin and stabilizes oxidative stress for a limited period [2]. At the same time, it can itself undergo oxidation upon UV-light, having negative effects on the skin after prolonged exposure, if not compensated by antioxidants [3]. It is known that oxidized squalene—namely squalene hydroperoxides—induces inflammatory processes in the skin and has a pro-aging and comedogenic effect [4,5,6,7,8]. That is why oxidative stabilization is necessary to preserve positive properties.
Nevertheless, the skin has its own protective systems, including sufficient sebum production, which facilitates the removal of oxidized lipids [9]. Therefore, a healthy concentration of squalene in the skin is essential for its health and regenerative capacity [10]. Previous studies suggest that skin resilience peaks in early adulthood and then declines continuously thereafter. Not only age is relevant, but also skin condition: in atopic dermatitis, UV radiation has been shown to have a greater effect on skin health, which, among many other factors, could also be related to the reduced natural squalene content of the skin [2]. Therefore, topical supplementation may help restore insufficient squalene levels in the skin, thereby restoring the skin’s antioxidant balance [10,11]. This may be achieved via topical application of cosmetic or medical emulsions.
As an ingredient for cosmetic, food, and pharmaceutical industries, for a considerable timeframe, the main source of squalene was shark liver oil. Due to restrictions on shark fishing and limitations of solvent-based extraction methods, renewable sources (e.g., oils from olive, cucurbit seeds, wine residue, tobacco, ginseng, nuts or microbial sources) and supercritical CO2 extraction have emerged as safer, more sustainable, and cost-effective alternatives [12]. Topically applied squalene benefits the skin by acting as an emollient, antioxidant, and anti-inflammatory agent that reinforces the skin barrier, improves hydration, promotes wound healing, reduces erythema and protects against oxidative stress and premature aging [13]. For more information on the multifunctional benefits of squalene for skin health, please refer to this comprehensive review by Morgan et al. (2024) [14]. Cosmetic and medical products containing squalene thus offer the potential to protect the skin from oxidative stress and environmental irritants, strengthen its natural suppleness and regenerative capacity, and reduce inflammatory processes, therefore preventing dermatitis and skin aging [11]. However, to counteract the risk of oxidative instability and its undesirable effects [4,5,6,7,8], in recent years, the raw material squalane, the hydrogenated form of squalene, has come into focus in the cosmetics industry. Although the chemical saturation makes the ingredient squalane significantly more stable during storage, it limits its function to a neutral emollient. Unlike squalene, the saturated substitute ingredient squalane has a similar molecular structure; however, missing unsaturated bonds and consequently missing comparable reductive properties. Despite the similarity in name, it is therefore not an adequate replacement for squalene. However, both are described as safe for use in cosmetics [15,16,17].
Although there are numerous in vitro, ex vivo, and animal studies as well as safety assessments on squalene [17], to the best of the authors’ knowledge, there are currently no studies that address the cosmetic/dermatological effects of squalene or squalene containing oils in topical emulsions (O/W or W/O) in -vivo studies or theoretical calculations. This raises the question of how feasible it is to use squalene or plant oils containing squalene in topical emulsions, and which raw materials would be suitable for this purpose. To address this, in this article various sources of squalene were compared regarding their composition and manufacturing process, and existing information from the literature on their effects and shelf life was discussed. This provides a basis for raw material suppliers and product manufacturers to evaluate the use of squalene and take appropriate measures to optimize its effectiveness.

2. Materials and Methods

This review presents a comparative analysis of different squalene sources, with a narrative focus on their chemical composition and production methods. Between October 2025 and January 2026, targeted literature searches were conducted in scientific databases, including PubMed, Scopus, Google Scholar and Web of Science, focusing on work addressing ‘squalene’, ‘squalane’, and ‘skin’. The research screened existing literature using keywords related to topical effects (‘skin’, ‘dermal’, ’topical’, ’cosmetic’, ’cosmeceutical ’, ’medical use’), plant-derived oil sources (’seed oil’, ’plant/vegetable/crop oil’, ’cold-pressed’, ’virgin oil’, ’extraction’, ’calibration’, ’standardization’, ‘GC-analysis’), and oxidative stability (‘squalene hydroperoxides’, ‘lipid oxidation’, ‘oxidative stress’, ‘stability’, ‘shelf life’, ‘storage conditions’, ‘oxidative degradation’). Relevant peer-reviewed publications on topical applications were included, with a focus on emulsions and oxidative stability, as well as oils derived from edible and non-edible crops—while excluding redundant, inaccessible, or methodologically insufficient studies. Title/abstract screening and full-text review followed to ensure transparency and reproducibility. Methods not using standard calibration but instead quantifying based on area ratios in the GC-chromatogram were marked. Although these approaches do not meet the requirements for reliable quantification, they still can serve as a semiquantitative guide given interest in the data. While English and German work was preferred, foreign-language literature was first translated by qualified translators or appropriate assistance systems to ensure accurate interpretation. No lower publication date limit was applied due to the historical relevance of early studies, to also incorporate foundational literature and original findings. Although broad search terms yielded many publications (e.g., ‘squalene’ and ‘skin’), only a limited subset directly addressed the physiological, botanical, ecological and oxidative aspects relevant to the scope of this analysis.
To complement the literature overview, limited exploratory third-party analytical data from instrumental analyses are provided in Appendix A.
This approach allowed us to synthesize current knowledge on the practical application of squalene in topical emulsions and to provide a foundation for raw material and product developers to assess its potential applications and optimize efficacy.

3. Results and Discussion

This chapter presents the results together with the relevant contextual discussion. The following subsections describe selected edible and non-edible sources of squalene, its chemical stability, and cosmetic potential. Supplementary data from instrumental analyses are provided in Appendix A.

3.1. Squalene Sources

Mechanical oil pressing or pressure extraction (e.g., with a screw press) is a process in which seeds, nuts, or fruits are mechanically crushed under high pressure to extract the oil they contain. Ideally, temperatures are kept as low as possible (known as “cold pressing”) to minimize thermal and chemical influences—this ensures that natural ingredients such as antioxidants, plant sterols, vitamins, and other secondary plant substances are better preserved [18]. For an overview of the squalene content of various plant, animal and microbial oils using other extraction methods, please refer to the review by Lozano-Grande et al. (2018) [19]. Although numerous squalene analyses of cold-pressed vegetable oils were found, the aim of this research was to compare established high-squalene sources narratively in order to achieve the best possible skin effectiveness at the lowest possible ingredient concentration in the cosmetic formulation and to find new sources that may meet these requirements. In this initial research, olive oils, amaranth oils, germ oils (e.g., rice, corn), and pumpkin seed oils exhibited the highest concentrations of squalene [20]. In Table 1, several analyses of currently known edible plant sources of squalene are compared.
Depending on the species, variety, and region of cultivation, cold-pressed oils vary greatly in their squalene content, even if the plant genus is the same. Even though some oils are known for their squalene content, it was still relatively low. Only amaranth oil showed a relevant squalene amount that might have a considerable effect on the skin in cosmetic formulations at a realistic concentration in application. However, due to its high price, it is not commonly used in large quantities in the cosmetics industry.
Therefore, lesser-known sources of oil were also considered. Although food oil crops have been bred for taste, smell, and yield, they deplete the soil and require a certain crop rotation and cultivation breaks. Plants that regenerate the soil and can be used during cultivation breaks are therefore a more sustainable source of oil. While taste and smell are important criteria for edible oils, a bitter taste or stronger smell is not crucial for cosmetic oils that are used for skin care and not in the mouth area. In the following comparison, not only food and feed crops were analyzed, but also green fertilizers and intercrops. Their advantage is that they do not compete with human nutrition and do not divert resources from the food supply. In addition, plants with short intervals between sowing and harvesting were selected, as long growth periods until optimal fruit formation pose a risk of loss due to drought or disease, as olive oil shows [30]. Table 2 compares these oils with each other [31].
Since secondary crops usually are not cultivated and optimized for oil quality, analytical results were limited. However, the results clearly show that Silphium oil provides the highest squalene content (>3%), exceeding even that of most established food oil sources. This ingredient is already approved for cosmetic use under the INCI name SILPHIUM PERFOLIATUM SEED OIL and has a high ecological value [43]. It is recognized in the EU CosIng/COSMILE database as a cosmetic ingredient with antioxidant, antimicrobial, astringent, and sebum-regulating functions, with no specific restrictions or concentration limits under the EU Cosmetic Regulation (EC) No. 1223/2009 [44,45]. To date, the ingredient is not included in any prohibition or restriction annexes in major cosmetic markets (EU, US, CN), indicating that it may be used in cosmetic formulations provided that general safety requirements are met and appropriate toxicological substantiation is available. Although smell and taste may not be of the greatest relevance for cosmetic products, Silphium oil has a pleasant nutty aroma and therefore appears to be particularly compatible with cosmetic applications.
However, the other green manure plant oils are not suitable for commercial use in cosmetics, either for their low squalene content, lack of approval or for potential topical toxicity. In addition, some of these are not yet approved or are very uncommon in practical use, due to, e.g., negative consumer associations.
The cultivation area and international dependencies should not be overlooked, giving greater importance to plants that can be widely cultivated. Additionally, cultivation in tropical regions combined with the extensive use of pesticides and fertilizers to increase yields, challenges the sustainability of many of the previously efficient oil sources [46]. However, Silphium perfoliatum shows a high oil yield of 15% (see Table 2), despite cultivation in colder regions on previously planted and exploited soil [43].
Overall, it can be shown that, measured in terms of squalene content and oil yield, Silphium oil might serve as a sustainable and efficient source of squalene for the future use in skin care among other well-established and emerging squalene sources. However, broader comparative studies are recommended, since semi-quantitative quantification methods used in many studies are not fully comparable and should still be interpreted with caution.

3.2. Oxidative Stability

To assess the stability of squalene, both its stability in oil as a raw material and in emulsion as a product were considered—specifically in terms of its reactivity with oxygen. Some publications investigated the stability of squalene in various vegetable oils: degradation under everyday conditions varies from insignificant losses to 47% [47], which illustrates that other components could control degradation. For example, a competitive reaction with other antioxidants has been described in olive oil, so that squalene remained stable and contributed little to oxidative spoilage [48]. In pumpkin seed oil, squalene showed a degradation of approximately 20% in the early stages of oxidation and remained stable as storage progressed, while tocopherol declined continuously [49]. This was also observed in olive oil [50]. However, according to initial analyses (Appendix A.1), squalene in Silphium oil did not degrade in significant quantities during storage of several years and was still quantified over 3%, independent of packaging material used. An oxidation-protective effect has also been described in rapeseed oil, where an addition of 0.5% squalene was even recommended to increase shelf life [51]. Hence, it becomes evident why Silphium oil with over 3% squalene (see Appendix A.1) and over 66% of poly-unsaturated fatty acids (PUFA), mainly linoleic acid (see Appendix A.3), appeared to be stable. This can also be proved by the low hexanal concentrations measured in Silphium perfoliatum oil of under 3 ppm (see Appendix A.2). Hexanal is known as a major volatile aldehyde breakdown product of omega-6 fatty acids such as linoleic acid [52]. Even though no regulatory limit exists at present, ingredient and product manufacturers define their own specifications, based on a rancidity perception threshold of 5–10 ppm in foodstuffs [53]. Despite years of storage and high PUFA-concentrations (see Appendix A.3), Silphium oil maintained low hexanal levels regardless of packaging and storage conditions (see Appendix A.2), indicating its resistance to rancidity and its consistently high quality without any sensory limitations. This demonstrates not only its long shelf life but also its suitability for skin care, as unsaturated fatty acids in topical emulsions are known for their beneficial effects on inflammatory skin conditions [54].
As mentioned at the beginning, the formation of prooxidative squalene degradation products [4,5,6,7,8] should be avoided. Literature shows that their formation can be clearly prevented by primary antioxidants in water-free oil phases [55]. However, in heterogeneous phase systems, this is more complex. While water-in-oil emulsions (W/O) are characterized by a continuous oil phase that is in direct contact with air and their stability towards oxygen is similar to that of pure oil [56], oil-in-water emulsions are able to oxidize faster than unhomogenized oil itself due to the large surface area of the dispersed oil droplets [57]. To date, cosmetic squalene emulsions have been underrepresented in the literature, even though pharmaceutical emulsions allow for a certain degree of transferability and have already demonstrated high efficacy and stability [58,59,60]. However, the high unsaturated fatty acid (PUFA) content of Silphium perfoliatum oil of over 66% (see Appendix A.3) should be considered when estimating the shelf life of emulsions. Literature shows, that emulsified rapeseed and sunflower oils with similar PUFA-amounts have rapid oxidation rates, especially in bright and warm storage [61,62,63]. It is recommended to check the stability of Silphium oil and formulations thereof using similar approaches in future work.
It can therefore be concluded that squalene in oils and emulsions is stable and additionally has a stabilizing effect on the matrix composition.

3.3. Potential for Skin-Care Products

Even though other molecules have a considerably higher antioxidant capacity (ORAC, DPPH assay), squalene has significant regenerative, radical-scavenging, and oxidative stress-reducing effects on body cells, partly because, as a cell membrane component, it may repair oxidative damage directly at the source [47]. This is a major advantage, as it exhibits relatively high stability with biologically relevant efficacy.
Both squalane and squalene are described as promising for cosmetic, nutritional, and pharmaceutical industries, as they exhibit anticancer, antioxidant, drug carrier, detoxifier, skin hydrating, and emollient activities in both living and in vitro models [13]. However, the hydrogenated molecular variant squalane is not discussed in detail in this paper. Due to its moisturizing, radical-scavenging, and anti-cancerogenic properties, squalene is particularly recommended for topical formulations, including classic lipid emulsions (O/W and W/O) and nanostructured lipid carriers [11]. It is discussed as a treatment for anti-inflammatory skin diseases [64]. Additionally, its stabilizing and regenerating effect on vitamin E [65] and unsaturated fatty acids (PUFA) [66] provides stabilization of these anti-inflammatory and soothing ingredients in skin care products for dermatitis and psoriasis [67,68] to extend the shelf life and efficacy of these products. A high amount of unsaturated fatty acids was also identified in Silphium oil [69,70] (Appendix A.3), making it a promising source for skin caring and wound healing emulsions [54].
In addition to oxidative stability, physical emulsion stability is also relevant for cosmetic products—this has already been proven for squalene-containing O/W emulsions with 2% emulsifier and 2–10% squalene under various storage conditions [71]. Chitosan and whey protein [72] as well as phosphatidylcholine [73] also showed good stabilizing properties. A stable nano-emulsion for cosmetic applications has also been described in the literature [74]. Initial application tests (see Appendix A.4) showed good emulsifiability at 15% and a pleasant emulsion texture in a base formulation—however, further testing in more complex formulations, packaging materials and storage variations is recommended. This indicates that there are neither physical nor oxidative limitations to the development of a marketable skin care product containing squalene.
In addition to technological feasibility, there is also the question of effectiveness. Although squalene has been described as having many beneficial effects on the skin, a critical concentration for application has not yet been established. This proposed initial approach is based on knowledge of the natural squalene concentration of the skin, the amount of skin care products used, the concentration of squalene in oil, and oil in a topical skin care product. Even though the lipid content of human skin varies depending on the area of the body, between 57 and 288 µg/cm2 of sebum was produced within 12 h by male subjects, of which 8.1–11.2% was squalene; after 3 h, the amount produced was 19–160 µg/cm2 with 6.2–13.5% squalene [75]. Accordingly, each square centimeter of healthy male skin should contain 4.6–29.1 µg of squalene in 12 h. Another publication described an amount of 139 ± 28 µg squalene per biopsy area measuring 4 mm in diameter which corresponds to 1103.2 ± 222 µg/cm2 [76]. Even though this value better describes the skin’s content as it is extracted from a complete skin biopsy, the content of superficial sebum for further calculations was used, as this is most applicable to the use of topical cosmetics. However, due to the limited availability of usable data for other demographic and skin types, calculations will continue using this data based on male skin as a temporary and estimative measure. Nevertheless, a review of all genders and age groups is recommended, as hormone concentration can affect sebum production [77].
In accordance with the Commission’s recommendation, the application amount for cosmetic products of 2 mg/cm2 of skin was included in the calculation [78]. It is well known that with increasing UV radiation and the resulting oxidative stress, a linearly proportional amount of squalene is consumed to protect the skin—this process is significantly increased in atopic skin [2]. This is due to the reduced amount of sebum (approx. 30% less in non-lesional skin and 50% less in lesional skin of patients with atopic dermatitis) and its altered composition [79]. Since cosmetic products are intended to nourish and protect the skin, while healing is achieved with medical products, only the numbers for non-lesional skin were included for further calculation. Therefore, a topical skin care product would need to deliver 1.4–8.7 µg/cm2 of squalene to restore healthy levels, assuming that cosmetic products are used twice a day (every 12 h, since both sebum and topical care products might be worn off). If this amount were contained in 2 mg of a skin care product, it would correspond to 70–430 mg/100 g product. The following scheme illustrates the individual steps of this calculation (Figure 1).
Assuming a squalene concentration of 3.4% as in silphium seed oil, this would correspond to an application concentration of 2.1–12.6% oil in an emulsion. These are standard concentrations used in O/W emulsions. The results indicate that with complete skin absorption, the healthy squalene concentration of sebum on the upper skin layer can be restored by a cosmetic product containing Silphium oil. The robustness of this calculation is demonstrated by the fact that even using twice the amount for skin care application would not exceed any regulatory safety margins of squalene. Considering that Silphium oil has no maximum regulatory threshold and many emulsions contain multi-fold higher oil-phase concentrations, consumers would also benefit from using even half than the amount typically specified in the safety assessment [22]. High-quality raw materials and stable formulations are essential requirements in each case.
Compared to other squalene sources, this calculation yields very different results: In some oils, including olive, Amaranthus and pumpkin seed oil [22,24,25], squalene concentration was too low for even 100% oil to meet the skin’s needs at the recommended application amount. Calculations based on other data sources [23,26,34,35,36,37,38], however, yielded formulation-relevant concentrations for pumpkin seed oil (12.1–72.4%), amaranth oil (1.2–7.4%), Silphium integrifolium (1.5–9.0%), and Pongamia pinnata (3.9–34.0%). While most mentioned oils are approved by regulatory authorities, no entries for Silphium integrifolium were found in the INCI databases. This suggests that, in addition to Silphium perfoliatum oil, other oils may also be suitable for supplementing the skin’s squalene content—subject to their topical applicability.
Although the results are promising, we recommend controlled, randomized, and double-blind studies to confirm these findings. It is particularly relevant that the data are based on male skin, whereas female skin in general, and in different phases of the menstrual cycle or at different ages, may differ, which should be investigated in more detail. Furthermore, the data here refers to the entire body. A distinction between different areas of the body should be taken into account in the study to avoid skin reactions caused by over-care.

4. Conclusions

Considering its biological activities, formulation compatibility, and sustainability profile, squalene represents a versatile and effective ingredient for future cosmetic applications, offering clear potential for innovation in modern skin care product development.
This review highlights the significant variability of squalene content across plant-derived oils and identifies Silphium perfoliatum as a possible sustainable and efficient new source with a high squalene yield per cultivated area, combined with favorable sensory properties. In addition, current evidence shows that squalene in plant oil exhibits notable oxidative stability. Its ability to protect and regenerate key bioactive compounds such as vitamin E and polyunsaturated fatty acids further underscores its value in skin-care formulations. Based on a calculation model, Silphium oil may compensate for the skin’s own squalene deficiencies at realistic application concentrations of 2.1–12.6% emulsified oil. Meanwhile, on the one hand, other plant oils reached concentrations between 1.5 and 72.4%, or on the other hand, were not concentrated enough even with 100% concentration in formulation or were not approved yet for cosmetic application.
Specific and actionable future research directions include storage trials to additionally demonstrate stability in emulsions under various storage conditions, as well as placebo-controlled skin efficacy studies using cosmetic or medical topical emulsions on affected and sensitive skin to confirm the efficacy of the calculated concentration.

5. Patents

This article is a literature-based review. The preparation or analysis of additional samples to improve comparability falls within standard scientific practice and the current state of the art. No new patents have been filed or are planned based on the content of this review.

Author Contributions

Conceptualization, A.S. and W.M.; methodology—literature research and data analysis, A.S.; methodology—sample analysis, A.S., C.G. and W.M.; visualization, A.S.; writing—original draft preparation, A.S.; writing—review and editing, A.S., C.G. and W.M.; supervision, A.S. and W.M. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding. The authors’ affiliated institution covered their working time, and A.S. was compensated as an independent as a Freelance Scientific Consultant for work related to this manuscript on an hourly fee-for-service basis under contract. Costs for instrumental analyses contracted with the specified partners and Article Processing Charge (APC) were covered by DOEHLER GmbH, Member of the DOEHLER GROUP, Riedstrasse 7-9, D-64295 Darmstadt.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

All data sources are listed in the references.

Acknowledgments

The authors gratefully acknowledge the contribution of the collaboration partners from University of Udine, Department of Agri-Food, Environmental and Animal Sciences for customization of their method and for conducting the squalene analyses, from PiCA Prüfinstitut Chemische Analytik GmbH for conducting the hexanal analyses and from UBF—Untersuchungs- und Forschungslaboratorium GmbH for the characterization of the fatty acid composition. Additionally, we would like to acknowledge the collaborative efforts and mutual support that contributed to the completion of this manuscript.

Conflicts of Interest

The funding sponsor had no role in the analysis or interpretation of the data and in the writing of the manuscript. Experimental analyses were conducted by independent external laboratories selected and contacted by A.S., based on analytical recommendations provided by A.S. Authors C.G. and W.M. are affiliated with the DOEHLER GROUP.

Appendix A

Appendix A.1. Squalene Analysis in Silphium Seed Oil

The seeds were stored for varying periods of time after cultivation, pressed in different years, and the oil was then stored in different packaging materials and under different storage conditions. The squalene content of the tested Silphium oil samples was determined by the University of Udine, Department of Agri-Food, Environmental and Animal Sciences, Via Sondrio 2a, 33100 Udine, Italy using HPLC-DAD, following a slightly modified method based on Hayakawa et al., 2020 [22]. Sample preparation consisted of a 1:40 dilution in 2-propanol before HPLC injection (injection volume: 5 µL). Detection was performed using a DAD set at 215 nm. A short validation demonstrated the following method performance:
  • linearity: R2 = 0.9987 over the calibration range 0.046–18.6 mg/kg of squalene;
  • repeatability (n = 7): RSD% = 0.2%;
  • mean recovery: 102.0 ± 0.3% evaluated at two concentration levels (0.460 and 0.920 g/kg).
The resulting squalene concentrations are fully reported in Table A1.
Table A1. Squalene content of the analyzed Silphium oil samples (determined by HPLC-DAD).
Table A1. Squalene content of the analyzed Silphium oil samples (determined by HPLC-DAD).
SampleCropPressedPackagingStorageBatchSqualene [mg/100 g]
12024April 2025HDPEDark, 15 °CPA250483250 ± 50
22018April 2025HDPEDark, 15 °CPA250503560 ± 1
32020April 2025HDPEDark, 15 °CPA250493350 ± 70
420222022HDPE Can, later transferred
to Green Glass		Dark, 15 °C-3560 ± 80
520222022GlassDark, 15 °C-3560 ± 4
620222022GlassOffice, Room Temperature-3490 ± 30
720222022GlassDark, 15 °C-3550 ± 20
The result shows consistent squalene concentration that is independent of storage conditions and packaging material.

Appendix A.2. Hexanal Analysis in Silphium Seed Oil

The concentration of n-hexanal was examined by PiCA Prüfinstitut Chemische Analytik GmbH, Rudower Chaussee 29, 12489 Berlin, Germany using GC-MS after aqueous extraction and derivatization with a detection limit of 1 ppm with estimated measurement uncertainty of ±35%. The results are listed in Table A2.
Table A2. Hexanal content of the analyzed Silphium oil samples (determined by GC-MS).
Table A2. Hexanal content of the analyzed Silphium oil samples (determined by GC-MS).
SampleCropPressedPackagingStorageBatchHexanal [ppm]
12024April 2025HDPEDark, 15 °CPA25048<1
22018April 2025HDPEDark, 15 °CPA250502.3
32020April 2025HDPEDark, 15 °CPA250491.1
420222022HDPE Can, later transferred to GlassDark, 15 °C-1.2
520222022GlassDark, 15 °C-1.4
620222022GlassOffice, Room Temperature-<1
720222022GlassDark, 15 °C-<1
This analysis shows an undetectable or very low hexanal concentration that is independent of storage conditions and packaging material, indicating high oxidation stability.

Appendix A.3. Fatty Acid Analysis in Silphium Seed Oil

The composition of fatty acids was examined by Untersuchungs- & Forschungslaboratorium (UBF) GmbH, An der Mühle 1d, 15345 Altlandsberg, Germany using a standardized gas chromatographic method. The results are listed in Table A3.
Table A3. Fatty acid composition analysis of selected Silphium oil samples (determined by GC).
Table A3. Fatty acid composition analysis of selected Silphium oil samples (determined by GC).
SampleCropPressedBatchPalmitic Acid [%]Stearic Acid [%]Oleic Acid [%]Linoleic Acid [%]
12024April 2025PA250487.02.317.469.2
22018April 2025PA250507.73.219.865.0
32020April 2025PA250497.22.518.666.4
The analysis reveals a high content of unsaturated fatty acids (PUFA) in all Silphium oil samples across different harvest times, highlighting the oil’s consistent skin-nourishing properties.

Appendix A.4. Application Potential of Silphium Seed Oil

The unprocessed Silphium oil appeared golden in color and had a nutty aroma. An initial application analysis in emulsions (Ingredients: 15% Silphium perfoliatum seed oil, 7% Glyceryl Stearate SE, 0.5% Phenylethanol, 0.3% Xanthan Gum, 0.1% Citric Acid, q.s. 100% Aqua) showed good emulsifiability. Production instructions were conducted in accordance with [61,62,63]. The result was a nutty-smelling, light beige, smooth emulsion with a lightly absorbent texture. More detailed stability and packaging compatibility tests are recommended.

References

  1. Pham, D.-M.; Boussouira, B.; Moyal, D.; Nguyen, Q.L. Oxidization of squalene, a human skin lipid: A new and reliable marker of environmental pollution studies. Int. J. Cosmet. Sci. 2015, 37, 357–365. [Google Scholar] [CrossRef] [Scilit]
  2. Kohno, Y.; Takahashi, M. Peroxidation in human skin and its prevention. J. Jpn. Oil Chem. Soc. 1995, 44, 248–255. [Google Scholar] [CrossRef] [Scilit]
  3. Auffray, B. Protection against singlet oxygen, the main actor of sebum squalene peroxidation during sun exposure, using Commiphora myrrha essential oil. Int. J. Cosmet. Sci. 2007, 29, 23–29. [Google Scholar] [CrossRef] [Scilit] [PubMed]
  4. Chiba, K.; Sone, T.; Kawakami, K.; Onoue, M. Skin roughness and wrinkle formation induced by repeated application of squalene-monohydroperoxide to the hairless mouse. Exp. Dermatol. 1999, 8, 471–479. [Google Scholar] [CrossRef] [Scilit]
  5. Chiba, K.; Yoshizawa, K.; Makino, I.; Kawakami, K.; Onoue, M. Comedogenicity of squalene monohydroperoxide in the skin after topical application. J. Toxicol. Sci. 2000, 25, 77–83. [Google Scholar] [CrossRef] [Scilit]
  6. Chiba, K.; Yoshizawa, K.; Makino, I.; Kawakami, K.; Onoue, M. Changes in the levels of glutathione after cellular and cutaneous damage induced by squalene monohydroperoxide. J. Biochem. Mol. Toxicol. 2001, 15, 150–158. [Google Scholar] [CrossRef] [Scilit] [PubMed]
  7. Chiba, K.; Kawakami, K.; Sone, T.; Onoue, M. Characteristics of skin wrinkling and dermal changes induced by repeated application of squalene monohydroperoxide to hairless mouse skin. Ski. Pharmacol. Appl. Ski. Physiol. 2003, 16, 242–251. [Google Scholar] [CrossRef] [Scilit]
  8. Uchino, T.; Tokunaga, H.; Onodera, H.; Ando, M. Effect of squalene monohydroperoxide on cytotoxicity and cytokine release in a three-dimensional human skin model and human epidermal keratinocytes. Biol. Pharm. Bull. 2002, 25, 605–610. [Google Scholar] [CrossRef] [Scilit] [PubMed]
  9. De Luca, C.; Valacchi, G. Surface lipids as multifunctional mediators of skin responses to environmental stimuli. Mediat. Inflamm. 2010, 2010, 321494. [Google Scholar] [CrossRef] [Scilit]
  10. Passi, S.; De Pità, O.; Grandinetti, M.; Simotti, C.; Littarru, G.P. The combined use of oral and topical lipophilic antioxidants increases their levels both in sebum and stratum corneum. Biofactors 2003, 18, 289–297. [Google Scholar] [CrossRef] [Scilit]
  11. Huang, Z.R.; Lin, Y.K.; Fang, J.Y. Biological and pharmacological activities of squalene and related compounds: Potential uses in cosmetic dermatology. Molecules 2009, 14, 540–554. [Google Scholar] [CrossRef] [Scilit] [PubMed]
  12. Rosales-Garcia, T.; Jimenez-Martinez, C.; Davila-Ortiz, G. Squalene Extraction: Biological Sources and Extraction Methods. Int. J. Environ. Agric. Biotechnol. 2017, 2, 1662–1670. [Google Scholar] [CrossRef] [Scilit]
  13. Kim, S.K.; Karadeniz, F. Biological Importance and Applications of Squalene and Squalane. In Advances in Food and Nutrition Research, 1st ed.; Elsevier Inc.: Amsterdam, The Netherlands, 2012; Volume 65, pp. 223–233. [Google Scholar] [CrossRef] [Scilit]
  14. Morgan, N.R.; Magalingam, K.B.; Radhakrishnan, A.K.; Arumugam, M.; Jamil, A.; Bhuvanendran, S. Explicating the Multifunctional Roles of Tocotrienol and Squalene in Promoting Skin Health. Ski. Health Dis. 2024, 4, ski2.448. [Google Scholar] [CrossRef] [Scilit] [PubMed]
  15. Micera, M.; Botto, A.; Geddo, F.; Antoniotti, S.; Bertea, C.M.; Levi, R.; Gallo, M.P.; Querio, G. Squalene: More than a Step toward Sterols. Antioxidants 2020, 9, 688. [Google Scholar] [CrossRef] [Scilit]
  16. Fiume, M.; Bergfeld, W.F.; Belsito, D.V.; Hill, R.A.; Klaassen, C.D.; Liebler, D.C.; Marks, J.G.; Shank, R.C.; Slaga, T.J.; Snyder, P.W.; et al. Squalane and Squalene. Int. J. Toxicol. 2023, 42, 107S–109S. [Google Scholar] [CrossRef] [Scilit] [PubMed]
  17. Fiume, M.M. Cosmetic Ingredient Review Expert Panel. In Safety Assessment of Squalane and Squalene as Used in Cosmetics; Cosmetic Ingredient Review: Washington, DC, USA, 2019; Available online: https://www.cir-safety.org/sites/default/files/Squalene%20and%20Squalane.pdf (accessed on 5 January 2026).
  18. Rathod, M.L.; Angadi, B.M.; Bhavi, I.G. A review on optimization of process parameters of cold pressed oil extraction for high output and for enhanced quality and retained nutrients. Food Humanit. 2025, 5, 100698. [Google Scholar] [CrossRef] [Scilit]
  19. Lozano-Grande, M.A.; Gorinstein, S.; Espitia-Rangel, E.; Dávila-Ortiz, G.; Martínez-Ayala, A.L. Plant Sources, Extraction Methods, and Uses of Squalene. Int. J. Agron. 2018, 2018, 1829160. [Google Scholar] [CrossRef] [Scilit]
  20. Tian, M.; Bai, Y.; Tian, H.; Zhao, X. The Chemical Composition and Health-Promoting Benefits of Vegetable Oils—A Review. Molecules 2023, 28, 6393. [Google Scholar] [CrossRef] [Scilit]
  21. Salvo, A.; La Torre, G.L.; Rotondo, A.; Mangano, V.; Casale, K.E.; Pellizzeri, V.; Clodoveo, M.L.; Corbo, F.; Cicero, N.; Dugo, G. Determination of squalene in organic extra virgin olive oils (EVOOs) by UPLC/PDA using a single-step SPE sample preparation. Food Anal. Methods 2017, 10, 1377–1385. [Google Scholar] [CrossRef] [Scilit]
  22. Hayakawa, T.; Yanagawa, M.; Yamamoto, A.; Aizawa, S.; Taga, A.; Mochizuki, N.; Itabashi, Y.; Uchida, H.; Ishihara, Y.; Kodama, S. A Simple Screening Method for Extra Virgin Olive Oil Adulteration by Determining Squalene and Tyrosol. J. Oleo Sci. 2020, 69, 677–684. [Google Scholar] [CrossRef] [Scilit]
  23. Akin, G.; Arslan, F.N.; Karuk Elmasa, S.N.; Yilmaz, I. Cold-pressed pumpkin seed (Cucurbita pepo L.) oils from the central Anatolia region of Turkey: Characterization of phytosterols, squalene, tocols, phenolic acids, carotenoids and fatty acid bioactive compounds. Grasas Aceites 2018, 69, e232. [Google Scholar] [CrossRef] [Scilit]
  24. Konopka, I.; Roszkowska, B.; Czaplicki, S.; Tańska, M. Optimization of Pumpkin Oil Recovery by Using Aqueous Enzymatic Extraction and Comparison of the Quality of the Obtained Oil with the Quality of Cold-Pressed Oil. Food Technol. Biotechnol. 2016, 54, 413–420. [Google Scholar] [CrossRef] [Scilit]
  25. Yuenyong, J.; Pokkanta, P.; Phuangsaijai, N.; Kittiwachana, S.; Mahatheeranont, S.; Sookwong, P. GC-MS and HPLC-DAD Analysis of Fatty Acid Profile and Functional Phytochemicals in Fifty Cold-Pressed Plant Oils in Thailand. Heliyon 2021, 7, e06304. [Google Scholar] [CrossRef] [Scilit]
  26. Bozorov, S.S.; Berdiev, N.S.; Ishimov, U.J.; Olimjonov, S.S.; Ziyavitdinov, J.F.; Asrorov, A.M.; Salikhov, S.I. Chemical Composition and Biological Activity of Seed Oil of Amaranth Varieties. Nova Biotechnol. Chim. 2018, 17, 66–73. [Google Scholar] [CrossRef] [Scilit]
  27. Mondor, M.; Melgar-Lalanne, G.; Hernández-Álvarez, A.J. Cold Pressed Amaranth (Amaranthus tricolor) Oil. In Cold Pressed Oils; Academic Press: London, UK, 2020; pp. 113–127. [Google Scholar]
  28. Pal, Y.P.; Pratap, A.P. Rice Bran Oil: A Versatile Source for Edible and Industrial Applications. J. Oleo Sci. 2017, 66, 551–556. [Google Scholar] [CrossRef] [Scilit]
  29. Pokkanta, P.; Sookwong, P.; Tanang, M.; Setchaiyan, S.; Boontakham, P.; Mahatheeranont, S. Simultaneous Determination of Tocols, γ-Oryzanols, Phytosterols, Squalene, Cholecalciferol and Phylloquinone in Rice Bran and Vegetable Oil Samples. Food Chem. 2018, 264, 424–433. [Google Scholar] [CrossRef] [Scilit]
  30. Wechsler, T.; Bakhshian, O.; Engelen, C.; Dag, A.; Ben-Ari, G.; Samach, A. Determining Reproductive Parameters, which Contribute to Variation in Yield of Olive Trees from Different Cultivars, Irrigation Regimes, Age and Location. Plants 2022, 11, 2414. [Google Scholar] [CrossRef] [Scilit]
  31. Kaniewski, D.; Marriner, N.; Terral, J.F.; Besnard, G.; Tsitsou, L.; Topsakal, J.; Morhange, C.; Otto, T.; Luce, F.; Cheddadi, R. Olive Production in the 21st Century Will Be Threatened by Water Stress and Declining Solar Activity. Commun. Earth Environ. 2025, 6, 268. [Google Scholar] [CrossRef] [Scilit]
  32. O’Neill, C.M.; Gill, S.; Hobbs, D.; Morgan, C.; Bancroft, I. Natural Variation for Seed Oil Composition in Arabidopsis thaliana. Phytochemistry 2003, 64, 1077–1090. [Google Scholar] [CrossRef] [Scilit]
  33. Kempinski, C.; Chappell, J. Engineering Triterpene Metabolism in the Oilseed of Arabidopsis thaliana. Plant Biotechnol. J. 2019, 17, 386–396. [Google Scholar] [CrossRef] [Scilit]
  34. Reinert, S.; Van Tassel, D.L.; Schlautman, B.; Kane, N.C.; Hulke, B.S. Assessment of the biogeographical variation of seed size and seed oil traits in wild Silphium integrifolium Michx. genotypes. Plant Genet. Resour. 2019, 17, 427–436. [Google Scholar] [CrossRef] [Scilit]
  35. Hwang, H.-S.; Liu, S.X.; Winkler-Moser, J.K.; Singh, M.; Van Tassel, D.L. Composition and oxidative stability of silflower (Silphium integrifolium) seed oil and its potential as a new source of squalene. J. Am. Oil Chem. Soc. 2024, 101, 663–674. [Google Scholar] [CrossRef] [Scilit]
  36. Thathsara, K.A.H.; Chinthaka, S.D.M. Characterization of seed oils of three Fabaceae species. In Proceedings of the Open University Research Sessions (OURS 2023); The Open University of Sri Lanka: Nawala, Sri Lanka, 2023; pp. 1–6. [Google Scholar]
  37. Prajapati, R.M.; Thakur, L.K.; Singh, U. Formulation and bio-efficacy of emulsifiable concentrates of Pongammia pinnata and Jatropha curcas seed oils against plant pathogens. Int. J. ChemTech Res. 2017, 10, 365–372. [Google Scholar]
  38. Panpraneecharoen, S.; Khamchum, C.; Vaithanomsat, P.; Thanasombat, M.; Punsuvon, V. Variability of oil content, fatty acid composition and karanjin content in Pongamia pinnata and its relationship with biodiesel quality. Annu. Res. Rev. Biol. 2014, 4, 2283–2294. [Google Scholar] [CrossRef] [Scilit]
  39. Li, C.; Ng, A.; Xie, L.; Mao, H.; Qiu, C.; Srinivasan, R.; Yin, Z.; Hong, Y. Engineering low phorbol ester Jatropha curcas seed by intercepting casbene biosynthesis. Plant Cell Rep. 2016, 35, 103–114. [Google Scholar] [CrossRef] [Scilit]
  40. Ashirov, M.Z.; Datkhayev, U.M.; Myrzakozha, D.A.; Sato, H.; Zhakipbekov, K.S.; Rakhymbayev, N.A.; Sadykov, B.N. Study of Cold-Pressed Tobacco Seed Oil Properties by Gas Chromatography Method. Sci. World J. 2020, 2020, 8852724. [Google Scholar] [CrossRef] [Scilit]
  41. Hou, X.; Zhang, H.; Zhang, Z.; Liang, H.; Fu, Y.; Fu, Q.; Mao, X.; Du, Y. Analysis of Tobacco Seed Oil and Its Antioxidant Activities in vivo. Chin. Tob. Sci. 2016, 37, 80–84. [Google Scholar]
  42. Matthäus, B.; Özcan, M.M. Fatty Acid, Tocopherol and Squalene Contents of Rosaceae Seed Oils. Bot. Stud. 2014, 55, 48. [Google Scholar] [CrossRef] [Scilit]
  43. Gansberger, M.; Montgomery, L.F.R.; Liebhard, P. Botanical characteristics, crop management and potential of Silphium perfoliatum L. as a renewable resource for biogas production: A review. Ind. Crops Prod. 2015, 63, 362–372. [Google Scholar] [CrossRef] [Scilit]
  44. Cosmile Europe. Silphium perfoliatum Seed Oil. Available online: https://cosmileeurope.eu/inci/detail/33460/silphium-perfoliatum-seed-oil/ (accessed on 9 May 2026).
  45. European Parliament; Council of the European Union. Regulation (EC) No 1223/2009 of the European Parliament and of the Council of 30 November 2009 on cosmetic products. Off. J. Eur. Union 2009, L342, 59–209. [Google Scholar]
  46. Mohd Hanafiah, K.; Abd Mutalib, A.H.; Miard, P.; Goh, C.S.; Mohd Sah, S.A.; Ruppert, N. Impact of Malaysian palm oil on sustainable development goals: Co-benefits and trade-offs across mitigation strategies. Sustain. Sci. 2022, 17, 1639–1661. [Google Scholar] [CrossRef] [Scilit]
  47. Amarowicz, R. Squalene: A natural antioxidant? Eur. J. Lipid Sci. Technol. 2009, 111, 411–412. [Google Scholar] [CrossRef] [Scilit]
  48. Psomiadou, E.; Tsimidou, M. On the role of squalene in olive oil stability. J. Agric. Food Chem. 1999, 47, 4025–4032. [Google Scholar] [CrossRef] [Scilit]
  49. Naziri, E.; Mitić, M.N.; Tsimidou, M.Z. Contribution of tocopherols and squalene to the oxidative stability of cold-pressed pumpkin seed oil (Cucurbita pepo L.). Eur. J. Lipid Sci. Technol. 2016, 118, 898–905. [Google Scholar] [CrossRef] [Scilit]
  50. Rastrelli, L.; Passi, S.; Ippolito, F.; Vacca, G.; De Simone, F. Rate of degradation of α-tocopherol, squalene, phenolics, and polyunsaturated fatty acids in olive oil during different storage conditions. J. Agric. Food Chem. 2002, 50, 5566–5570. [Google Scholar] [CrossRef] [Scilit]
  51. Malecka, M. The effect of squalene on the thermostability of rapeseed oil. Nahrung 1994, 38, 135–140. [Google Scholar] [CrossRef] [Scilit]
  52. Belitz, H.D.; Grosch, W.; Schieberle, P. Lehrbuch der Lebensmittelchemie, 6th ed.; Springer: Berlin/Heidelberg, Germany, 2013. [Google Scholar]
  53. Fritsch, C.W.; Gale, J.A. Hexanal as a measure of rancidity in low fat foods. J. Am. Oil Chem. Soc. 1977, 54, 225–228. [Google Scholar] [CrossRef] [Scilit]
  54. Ishak, W.M.W.; Katas, H.; Yuen, N.P.; Abdullah, M.A.; Zulfakar, M.H. Topical application of omega-3-, omega-6-, and omega-9-rich oil emulsions for cutaneous wound healing in rats. Drug Deliv. Transl. Res. 2019, 9, 418–433. [Google Scholar] [CrossRef] [Scilit]
  55. Naziri, E.; Consonni, R.; Tsimidou, M.Z. Squalene oxidation products: Monitoring the formation, characterisation and pro-oxidant activity. Eur. J. Lipid Sci. Technol. 2014, 116, 1400–1411. [Google Scholar] [CrossRef] [Scilit]
  56. Zhang, M.; Fan, L.; Liu, Y.; Li, J. Effects of interface generation, droplet size and antioxidant partitioning on the oxidation rate and oxidative stability of water–in–oil emulsions: A comparison of coarse emulsions and nanoemulsions. Food Hydrocoll. 2023, 136, 108227. [Google Scholar] [CrossRef] [Scilit]
  57. McClements, D.J.; Decker, E.A. Lipid oxidation in oil-in-water emulsions: Impact of molecular environment on chemical reactions in heterogeneous food systems. J. Food Sci. 2000, 65, 1270–1282. [Google Scholar] [CrossRef] [Scilit]
  58. Fox, C.B. Squalene Emulsions for Parenteral Vaccine and Drug Delivery. Molecules 2009, 14, 3286–3312. [Google Scholar] [CrossRef] [Scilit]
  59. Brito, L.A.; Chan, M.; Baudner, B.; Gallorini, S.; Santos, G.; O’Hagan, D.; Singh, M. An alternative renewable source of squalene for use in emulsion adjuvants. Vaccine 2011, 29, 6262–6268. [Google Scholar] [CrossRef] [Scilit]
  60. Chae, G.-E.; Kim, D.W.; Jin, H.-E. Development of Squalene-Based Oil-in-Water Emulsion Adjuvants Using a Self-Emulsifying Drug Delivery System for Enhanced Antigen-Specific Antibody Titers. Int. J. Nanomed. 2022, 17, 6221–6231. [Google Scholar] [CrossRef] [Scilit]
  61. Springer, A.; Ziegler, H. The Role of Preservatives and Multifunctionals on the Oxidation of Cosmetic O/W Emulsions. Cosmetics 2022, 9, 59. [Google Scholar] [CrossRef] [Scilit]
  62. Springer, A.; Ziegler, H.; Bach, K. The Influence of Antioxidant Plant Extracts on the Oxidation of O/W Emulsions. Cosmetics 2023, 10, 40. [Google Scholar] [CrossRef] [Scilit]
  63. Rosenow, P.; Destler, E.; Springer, A. The Search for Suitable Packaging for Cosmetics—A Case Study. Sofw. J. 2022, 148, 56–59. [Google Scholar]
  64. Styrczewska, M.; Zuk, M.; Boba, A.; Zalewski, I.; Kulma, A. Use of Natural Components Derived from Oil Seed Plants for Treatment of Inflammatory Skin Diseases. Curr. Pharm. Des. 2019, 25, 2241–2263. [Google Scholar] [CrossRef] [Scilit]
  65. Psomiadou, E.; Tsimidou, M.Z. Stability of virgin olive oil. 2. Photo-oxidation studies. J. Agric. Food Chem. 2002, 50, 722–727. [Google Scholar] [CrossRef] [Scilit]
  66. Dessi, M.A.; Deiana, M.; Day, B.W.; Rosa, A.; Banni, S.; Corongiu, F.P. Oxidative stability of polyunsaturated fatty acids: Effect of squalene. Eur. J. Lipid Sci. Technol. 2002, 104, 506–512. [Google Scholar] [CrossRef] [Scilit]
  67. Ferreira, M.J.; Fiadeiro, T.; Silvia, M.; Soares, A.P. Topical γ-linolenic acid therapy in atopic dermatitis. Allergo J. 1998, 7, 213–216. [Google Scholar] [CrossRef] [Scilit]
  68. Williams, H.C. Evening primrose oil for atopic dermatitis. BMJ 2003, 327, 1358–1359. [Google Scholar] [CrossRef] [Scilit]
  69. Kowalski, R. Studies of selected plant raw materials as alternative sources of triterpenes of oleanolic and ursolic acid types. J. Agric. Food Chem. 2007, 55, 656–662. [Google Scholar] [CrossRef] [Scilit] [PubMed]
  70. Kowalski, R.; Wierciński, J. Evaluation of chemical composition of some Silphium L. species seeds as alternative foodstuff raw materials. Pol. J. Food Nutr. Sci. 2004, 13, 349–354. [Google Scholar]
  71. Anghelache, A.M.; Kim, L.; Cuciureanu, A.; Bătrînescu, G.; Pascu, L.F. Rheological properties and stability of squalene emulsion prepared with non-ionic emulsifier. Rev. Chim. 2017, 68, 1681–1684. [Google Scholar] [CrossRef] [Scilit]
  72. Kumar, L.R.G.; Anas, K.K.; Tejpal, S.C.; Chatterjee, S.N.; Vishnu, V.K.; Asha, K.K.; Anandan, R.; Mathew, S. Chitosan: Whey Protein Isolate: An Effective Emulsifier for Stabilization of Squalene Based Emulsions. Waste Biomass Valoriz. 2020, 11, 3477–3483. [Google Scholar] [CrossRef] [Scilit]
  73. Fox, C.B.; Lin, S.; Sivananthan, S.J.; Dutill, T.S.; Forseth, K.T.; Reed, S.G.; Vedvick, T.S. Effects of emulsifier concentration, composition, and order of addition in squalene-phosphatidylcholine oil-in-water emulsions. Pharm. Dev. Technol. 2011, 16, 511–519. [Google Scholar] [CrossRef] [Scilit]
  74. Park, J.; Kang, D.H.; Woo, H.M. Microbial Bioprocess for Extracellular Squalene Production and Formulation of Nanoemulsions. ACS Sustain. Chem. Eng. 2021, 9, 14263–14276. [Google Scholar] [CrossRef] [Scilit]
  75. Greene, R.S.; Downing, D.T.; Pochi, P.E.; Strauss, J.S. Anatomical Variation in the Amount and Composition of Human Skin Surface Lipid. J. Investig. Dermatol. 1970, 54, 240–247. [Google Scholar] [CrossRef] [Scilit]
  76. Downing, D.T.; Stewart, M.E.; Strauss, J.S. Estimation of Sebum Production Rates in Man by Measurement of the Squalene Content of Skin Biopsies. J. Investig. Dermatol. 1981, 77, 358–360. [Google Scholar] [CrossRef] [Scilit] [PubMed]
  77. Luebberding, S.; Krueger, N.; Kerscher, M. Skin physiology in men and women: In vivo evaluation of 300 people including TEWL, SC hydration, sebum content and skin surface pH. Int. J. Cosmet. Sci. 2013, 35, 477–483. [Google Scholar] [CrossRef] [Scilit] [PubMed]
  78. European Commission. Commission Recommendation of 22 September 2006 on the Efficacy of Sunscreen Products and the Claims Made Relating Thereto (2006/647/EC). Off. J. Eur. Union 2006, L265, 39–43. [Google Scholar]
  79. Yin, H.; Qiu, Z.; Zhu, R.; Wang, S.; Gu, C.; Yao, X.; Li, W. Dysregulated lipidome of sebum in patients with atopic dermatitis. Allergy 2023, 78, 1524–1537. [Google Scholar] [CrossRef] [Scilit] [PubMed]
Cosmetics 13 00148 g001
Figure 1. Scheme illustrating the calculation steps used to determine the required squalene concentration for compromised skin, which is supplemented through topical application of squalene-containing oil, based on the squalene content of healthy skin.
Figure 1. Scheme illustrating the calculation steps used to determine the required squalene concentration for compromised skin, which is supplemented through topical application of squalene-containing oil, based on the squalene content of healthy skin.
Cosmetics 13 00148 g001
Table 1. Established Sources of Squalene in Plant Oils and their Concentration (mg per 100 g).
Table 1. Established Sources of Squalene in Plant Oils and their Concentration (mg per 100 g).
Established SourcesSqualene Mean (Range) [mg/100 g]Ref.
Extra Virgin Olive Oil (Olea europaea) 1,2372 (145–747)[21]
Olive Oil (Olea europaea) 3438 (236–747) *[22]
Pumpkin Seed Oil (Cucurbita pepo) 1605 (591–633)[23]
Pumpkin Seed Oil (Cucurbita pepo) 195 (95–96)[24]
Amaranth oil 473 (67–79)[25]
Amaranth Oil (Amaranthus hypochondriacus, Amaranthus cruentus) 2,45920 (5290–6790)[26]
Amaranth Oil (Amaranthus tricolor) 1(6000–11,600)[27]
Rice bran oil (Oryza sativa)326 (300–400)[22,28]
Peanut Oil (Arachis hypogaea) 1133 (132–134)[29]
Sunflower Oil (Helianthus annuus)8 (3–12) *[22]
1 different varieties; 2 different regions; 3 different qualities; 4 different species. * converted to mg/100 g with a density of 0.9 g/cm3.
Table 2. New Sources of Squalene in Plant Oils and their Concentration (mg per 100 g).
Table 2. New Sources of Squalene in Plant Oils and their Concentration (mg per 100 g).
New SourcesOil Content [%]Squalene Mean (Range) [mg/100 g]Ref.
Arabidopsis thaliana34.6–46.046–65 *[32,33]
Silphium perfoliatum153474 (3250–3560)Appendix A.1
Silphium integrifolium11.8–25.34890 **[34,35]
Pongamia pinnata26.7–33.11290–1860 **[36,37,38]
Jatropha curcas40180 **[36,39]
Nicotiana spp.36.25–37.2524 **[40,41]
Rosaceae seed oils3.49–46.1588.4 (20–290) **[42]
* Calculation based on seed oil content and squalene content per seed. Analysis of oil may result in different matrix effects. ** Semi-quantitative analysis based on GC peak area ratios. Quantification using standard calibration or standard addition might provide different results.
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Springer, A.; Gras, C.; Moor, W. Squalene from Silphium perfoliatum: A Novel Source with Long-Term Stability and Applicability in Topical Formulations. Cosmetics 2026, 13, 148. https://doi.org/10.3390/cosmetics13030148

AMA Style

Springer A, Gras C, Moor W. Squalene from Silphium perfoliatum: A Novel Source with Long-Term Stability and Applicability in Topical Formulations. Cosmetics. 2026; 13(3):148. https://doi.org/10.3390/cosmetics13030148

Chicago/Turabian Style

Springer, Arielle, Claudia Gras, and Willi Moor. 2026. "Squalene from Silphium perfoliatum: A Novel Source with Long-Term Stability and Applicability in Topical Formulations" Cosmetics 13, no. 3: 148. https://doi.org/10.3390/cosmetics13030148

APA Style

Springer, A., Gras, C., & Moor, W. (2026). Squalene from Silphium perfoliatum: A Novel Source with Long-Term Stability and Applicability in Topical Formulations. Cosmetics, 13(3), 148. https://doi.org/10.3390/cosmetics13030148

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