Trends in Protein Supplement Use Among Non-Professional Athletes: Insights from a Survey in Greece

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study is well-designed and, following appropriate data handling, allows for moderate but relevant conclusions. The investigation into protein supplement consumption yielded several interesting findings. Differences in gender, age, and motivational factors highlight some novel aspects worthy of further consideration. One of the strengths of the data analysis lies in the insights gained from monitoring increased protein intake.

It is surprising that a relatively high frequency of side effects was reported by respondents. Further information would be necessary in this regard. While the manuscript provides details on the forms of protein supplements chosen by consumers, it lacks information on the actual amounts consumed. It is therefore recommended that the side effect data be presented in a table to enhance clarity and accessibility.

 

Author Response

Reviewer 1

Dear Reviewer

Thank you for the positive feedback. We appreciate your constructive comments, and we addressed them carefully.

C: Comments

A: Answers

 

C: The study is well-designed and, following appropriate data handling, allows for moderate but relevant conclusions. The investigation into protein supplement consumption yielded several interesting findings. Differences in gender, age, and motivational factors highlight some novel aspects worthy of further consideration. One of the strengths of the data analysis lies in the insights gained from monitoring increased protein intake.

It is surprising that a relatively high frequency of side effects was reported by respondents. Further information would be necessary in this regard. While the manuscript provides details on the forms of protein supplements chosen by consumers, it lacks information on the actual amounts consumed. It is therefore recommended that the side effect data be presented in a table to enhance clarity and accessibility.

A: Thank you for your suggestions. We have included two figures to describe better the types of protein supplements commonly used by participants, differentiating by age, gender, and type of physical activity (PA), as well as a figure regarding the side effects reported. We hope that this will be beneficial for the reader to have a clear view of our outcomes. Lines 208 & 226

Reviewer 2 Report

Comments and Suggestions for Authors

In Figure 2, please add % number beside description on the right.

Since gender and age are listed separately, we cannot see the difference in gender by age. For example, can we see whether there are more men or more women in the 25-44 age group?

It would also be better to show the correlation between each factor in the reasons for protein intake, such as age, gender, and BMI.

In this study, there was no investigation on what kind of protein was consumed? Also, there was no investigation on whether protein was consumed through food or supplements? Can you differentiate the protein content for the protein intake methods mentioned in lines 165-170?

I think it would be good if the content of the results were unified. I would like to describe all the content in the text in a table or in a figure. Some content in the text is not in the table or figure, making it difficult to understand the content right away. For example, Line 173~176 side effects of PS and line 181~189 should be described in the tables.

The conclusion only describes the content related to protein product management. It is necessary to describe what the results imply and what the limitations are based on the research results.

Author Response

Reviewer 2

Dear Reviewer

Thank you for the feedback. We appreciate your constructive comments, and we addressed them carefully.

C: Comments

A: Answers

C: In Figure 2, please add % number beside description on the right.

A: Thank you for your suggestions, we have slightly changed the graph format to make the percentage number % visible. Line 182

C: Since gender and age are listed separately, we cannot see the difference in gender by age. For example, can we see whether there are more men or more women in the 25-44 age group?

A: Thank you for your suggestions. We have included the relevant stratification in Table 1, showing the differences by gender for age groups and BMI groups. Line 148

C: It would also be better to show the correlation between each factor in the reasons for protein intake, such as age, gender, and BMI.

A: Thank you for your suggestions. We have included a Table showing the Cramer V values of these correlations. Line 190

C: In this study, there was no investigation on what kind of protein was consumed? Also, there was no investigation on whether protein was consumed through food or supplements? Can you differentiate the protein content for the protein intake methods mentioned in lines 165-170?

A: Thank you for your suggestions. We have included some clarifications in the manuscript that we hope will be beneficial for the reader to have a better view of the data we aimed to collect in this survey. Our study specifically focused on PS use and did not collect data on the types of protein consumed, such as whey, casein, plant-based or on total protein intake from food sources. The questionnaire was designed to assess general PS consumption behaviors, beliefs, and perceptions among physically active participants. We acknowledge this limitation and have included a statement in the study limitation section: Total dietary protein intake was not assessed, which could have influenced participants' protein supplementation choices. Future research should incorporate detailed assessments of both total dietary protein intake and protein types to clarify the relationship between baseline intake and supplementation patterns

C: I think it would be good if the content of the results were unified. I would like to describe all the content in the text in a table or in a figure. Some content in the text is not in the table or figure, making it difficult to understand the content right away. For example, Line 173~176 side effects of PS and line 181~189 should be described in the tables.

A: Thank you for your suggestions. We have included some additional figures to make it easier to follow the narrative of the manuscript.

C: The conclusion only describes the content related to protein product management. It is necessary to describe what the results imply and what the limitations are based on the research results

A: Thank you for your suggestions. The conclusion and implications of the study have been revised as follows:

This study contributes to the growing body of research on PS consumption among non-professional athletes, a population that has been less extensively studied compared to elite athletes. Our findings highlight key demographic, behavioral, and motivational factors influencing PS use, reinforcing trends observed in previous literature. While PS has recognized benefits the reported side effects among PS users underscore the importance of consumer awareness and regulatory oversight. Despite the wide use of PSs, misconceptions persist regarding their regulation and safety, with many participants relying on non-professional information sources. This study emphasises the need for targeted educational initiatives to improve awareness of safe PS practices among non-professional athletes and fitness practitioners. Regulatory bodies should consider strengthening supplement oversight to ensure product quality and accurate labeling. The findings underline the importance of HCPs in guiding supplement decisions and suggest the value of culturally tailored public health strategies. Future research including longitudinal studies and randomized controlled trials needs to further assess long-term health effects and optimal use of PS in non-professional athletes. 

The limitations have been added in the discussion section in response to Reviewer 3 line 320:

The findings of this study have to be seen in light of some limitations. The description of exercise intensity was based on each respondent’s self-perception, which may not accurately reflect the actual intensity of their exercise practices. The survey relied on self-reported data for PS use, motivations, and health perceptions, which may introduce bias or social desirability bias. Total dietary protein intake was not assessed, which could have influenced participants' protein supplementation choices. Future research should incorporate detailed assessments of both total dietary protein intake and protein types to clarify the relationship between baseline intake and supplementation patterns. Additionally, the study was conducted within a specific cultural context, and cultural differences may affect the generalizability of the findings to other populations. Future research should expand on these findings by incorporating more diverse, and culturally varied samples to validate the results, reduce bias, and explore demographic patterns and motivational factors and health perceptions across different populations and food cultures. Regardless of these limitations, this research provides a foundation for future studies, including randomized controlled trials, that can address these challenges and integrate PS use with safety considerations into the lifestyles of non-professional athletes.

Reviewer 3 Report

Comments and Suggestions for Authors

A topic that has been widely explored, particularly among athletes and exercising individuals. It is not clear what novel information this manuscript brings, especially for the Greek community. Also, english editing is needed in different parts of the manuscript. Authors need to support the need and the rationale for this study before being considered for publication.

. Title: english editing needed; e.g. insights from a survey in Greece...not "for". 

. Abstract: Methods section needs to be rewritten - authors need to expand on areas from which participants were recruited, characteristics / inclusion criteria of participants, questionnaire used and information/categories collected in this questionnaire; also, authors need to briefly mention about their stats analysis methods - authors should describe the stats methods used to get all the results' outcomes, including regression analysis and others. Results section lacks some clarity - i.e. what do numbers in parenthesis mean? 

. Keywords: keywords should also reflect motivations, use, and safety as they were assessed in this study. 

. Introduction: English editing needed. Line 44: abbreviations not to be used at the beginning of sentences. This topic has been very widely explored worldwide, including in Greece; multiple studies have explored supplement use including the use of PS among athletes and exercisers in Greece - those studies were not cited by the authors. Overall, the originality of this work is not clear…authors need to better support the rationale and the need for this study. 

. Results: section 2.1: the section of the questionnaire regarding demographics was not mentioned in the Methods section - needs to be described in there. Also, in the questionnaire, it is not clear if authors asked about a variety of dietary supplements or only Protein supplements - this also needs to be clarified in the Methods section. 

Table 1: abbreviations like BMI should be explained in the footnotes. Also, authors should add in the footnotes what p value is considered significant, and what bolded p values mean. 

Figure 1: is there a way to display the p values in the figure? 

Line 150: the 51 is repeated twice- english editing is needed.

Table 2: again, sections reported in this table were not clearly described in the Methods section - need to be clearly described in there. Abbreviations like HCPs need to be explained in the footnotes. Also, in the footnotes, what a significant p value is and what bolded p values mean need to be clarified.  Also, it is not clear what those p values represent…a comparison? an association? this needs to be clarified in the footnotes. 

. Discussion: lines 206-218 - need to be relocated to the Results section. The Discussion section needs to discuss not restate the findings of the study. The Discussion section is very weak:
. lack comparisons to findings from Greece, the Mediterranean region and worldwide, 
. lacks discussion of the limitations of the study,
. and lacks discussion of the strengths of the study.

. Materials and Methods: the Methods section lacks details on many aspects of the study:
. validation of the questionnaire on the targeted population
. representation of the sample for the physically active Greek population
. and sample size calculation and appropriateness

. Conclusions: no p values need to be mentioned in the discussion or conclusion section (line 297). Line 300: long term health effects of what? - this needs to be clarified. 

. References: up to date. Needs to be expanded to cover more accurately the literature on this topic. 

Author Response

Reviewer 3

Dear Reviewer

Thank you for the feedback. We appreciate your constructive comments, and we addressed them carefully.

C: Comments

A: Answers

 

C: A topic that has been widely explored, particularly among athletes and exercising individuals. It is not clear what novel information this manuscript brings, especially for the Greek community. Also, english editing is needed in different parts of the manuscript. Authors need to support the need and the rationale for this study before being considered for publication.

A: We appreciate your thoughtful feedback. While the topic of PS use has indeed been widely explored on elite/professional athletes, our study offers novel insights by focusing on non-professional athletes and fitness practitioners in Greece. Our investigation into PS consumption revealed several noteworthy findings. Differences in gender, age, BMI,         and motivational factors emphasize underexplored aspects of PS use, particularly among non-professional athletes and fitness enthusiasts. A key strength of this analysis is the insight gained into consumption behaviors and perceptions, highlighting the need for further research to inform educational and regulatory strategies. These findings contribute valuable knowledge to the limited existing literature, particularly within the Greek context. In addition, we have thoroughly revised the manuscript for clarity and language quality to address the English editing concerns.

This rationale has been added to the Introduction section of the manuscript:

The majority of previous research has concentrated on elite or professional athletes, with limited evidence available on the beliefs, attitudes, and practices of non-professional athletes and fitness enthusiasts regarding PS use. Moreover, there is insufficient evidence regarding the complex interplay of factors influencing PS use, including individual motivations, sources of information, and awareness of regulatory frameworks and potential health risks among this diverse and recreationally active population. Considering the increasing popularity of fitness culture, the evolving supplement market, and changing consumer behaviors, it is essential to investigate current patterns of PS use and perceptions among non-professional athletes.  The current cross-sectional study aimed to address these gaps by investigating: (a) the beliefs and attitudes of physically active individuals regarding their PS use patterns and motivations; (b) protein supplement users’ sources of information and awareness of regulatory frameworks for supplement safety; (c) users’ perceptions of health risks associated with PS intake, including experiences of adverse side effects

C: Title: english editing needed; e.g. insights from a survey in Greece...not "for". 

A: Thank you for your suggestion. We modified it.

C: Abstract: Methods section needs to be rewritten - authors need to expand on areas from which participants were recruited, characteristics / inclusion criteria of participants, questionnaire used and information/categories collected in this questionnaire; also, authors need to briefly mention about their stats analysis methods - authors should describe the stats methods used to get all the results' outcomes, including regression analysis and others. Results section lacks some clarity - i.e. what do numbers in parenthesis mean? 

A: Thank you for your suggestion. Given the limit of words in the abstract, we made some modifications to increase clarity for the readers. Additional insights will need to be detailed in the main text. Line 23-25

C: Keywords: keywords should also reflect motivations, use, and safety as they were assessed in this study. 

A: We included the keywords, ergogenic supplements, participation, and legal, aligning with your guidance to include keywords reflecting motivations, use, and safety. Line 41

C: Introduction: English editing needed. Line 44: abbreviations not to be used at the beginning of sentences. This topic has been very widely explored worldwide, including in Greece; multiple studies have explored supplement use including the use of PS among athletes and exercisers in Greece - those studies were not cited by the authors. Overall, the originality of this work is not clear…authors need to better support the rationale and the need for this study. 

A: Thank you for your valuable comments. This study provides novel insights into protein supplementation related to gender, age, and motivational factors by examining non-professional athletes and general fitness practitioners, an area where evidence in Greece remains limited

We have revised our introduction and added the following paragraphs to the manuscript in response to your valuable observations:

We have revised the sentence to replace the abbreviation ‘ PSs’  with ‘ they’ . 

Acknowledgment of previous studies

Poulios et al. concluded that while some studies suggest PSs may relieve muscle soreness, reduce muscle damage markers, and moderate inflammation, the evidence is too limited and inconsistent to support clear guidelines for their use in team sport recovery. Karpouzi et al reported that increasing protein intake from 1.0 to 1.6 g/kg/day did not enhance performance outcomes, suggesting that short-term high-intensity functional training (HIFT) improvements in exercise capacity, upper-body strength, and core endurance were not influenced by PS [9]. Interestingly, they found that Pilates improved core endurance, flexibility, and body composition, but protein supplementation (0.6 g/kg) had no additional effect[10]. Tsitsimpikou et al. (2011) reported that 41% of recreational athletes in Athens consumed supplements, primarily proteins and amino acids, with limited professional guidance. Similarly, research among Mediterranean athletes indicated that supplementation often exceeded dietary needs (The Mediterranean Athlete’s Nutrition, 2020). Internationally, high prevalence rates of supplement use have been observed among elite athletes in Spain (64%) and recreational triathletes in Brazil (90.2%), often without adequate professional consultation or awareness of supplement safety (Prevalence of Dietary Supplement Use in Elite Spanish Athletes, 2019; Prevalence of Dietary Supplement Use Among Male Brazilian Recreational Triathletes, 2023).

Rationale of the Study

The majority of previous research has concentrated on elite or professional athletes, with limited evidence available on the beliefs, attitudes, and practices of non-professional athletes and fitness enthusiasts regarding PS use. Moreover, there is insufficient evidence regarding the complex interplay of factors influencing PS use, including individual motivations, sources of information, and awareness of regulatory frameworks and potential health risks among this diverse and recreationally active population. Considering the increasing popularity of fitness culture, the evolving supplement market, and changing consumer behaviors, it is essential to investigate current patterns of PS use and perceptions among non-professional athletes.  The current cross-sectional study aimed to address these gaps by investigating: (a) the beliefs and attitudes of physically active individuals regarding their PS use patterns and motivations; (b) protein supplement users’ sources of information and awareness of regulatory frameworks for supplement safety; (c) users’ perceptions of health risks associated with PS intake, including experiences of adverse side effects.

C: Results: section 2.1: the section of the questionnaire regarding demographics was not mentioned in the Methods section - needs to be described in there. Also, in the questionnaire, it is not clear if authors asked about a variety of dietary supplements or only Protein supplements - this also needs to be clarified in the Methods section. 

A: Thank you for your valuable feedback. We have added the demographics description to the Methods section: The first part of the questionnaire collected demographic information, including gender, age, anthropometric data , educational level, occupation (including whether it was sports-related), place of residence, and lifestyle habits such smoking, frequency of exercise (”low”, “moderate”, or “hard“) and type of exercise (‘Fitness’, ‘Aerobic’ , ‘Anaerobic, ‘Mixed Exercise’ ) . This information was used to assess potential associations between participant characteristics and PS use. Additionally, it included a single question on the use of any type of dietary supplements (e.g., vitamins, minerals, fatty acids, probiotics, herbal extracts, amino acids, etc.), designed to capture overall dietary supplement usage. 

C: Table 1: abbreviations like BMI should be explained in the footnotes. Also, authors should add in the footnotes what p value is considered significant, and what bolded p values mean. 

A: Thank you for your suggestion. We modified it. Line 149

C: Figure 1: is there a way to display the p values in the figure? 

A: Thank you for your suggestion. We modified it.

C: Line 150: the 51 is repeated twice- english editing is needed.

A: Thank you for your suggestion. We modified it.

C: Table 2: again, sections reported in this table were not clearly described in the Methods section - need to be clearly described in there. Abbreviations like HCPs need to be explained in the footnotes. Also, in the footnotes, what a significant p value is and what bolded p values mean need to be clarified.  Also, it is not clear what those p values represent…a comparison? an association? this needs to be clarified in the footnotes. 

A: We included the explanation of the abbreviations and the p-values. Lines 207-208, and addressed your comments in the Methods section: The first part of the questionnaire collected demographic information, including gender, age, anthropometric data, educational level, occupation (including whether it was sports-related), place of residence, and lifestyle habits such smoking, frequency of exercise (”low”, “moderate”, or “hard“) and type of exercise (‘Fitness’, ‘Aerobic’, ‘Anaerobic, ‘Mixed Exercise’). This information was used to assess potential associations between participant characteristics and PS use. Additionally, it included a single question on the use of any type of dietary supplements (e.g., vitamins, minerals, fatty acids, probiotics, herbal extracts, amino acids, etc.), designed to capture overall dietary supplement usage. 

The second part of the questionnaire targeted only those who had used PSs as part of their diet for at least one year prior to their participation in the survey. It included questions concerning PS use, knowledge, and perceptions of PS, sources of information regarding PS usage, legal aspects of supplement consumption, and associated negative health consequences

C: Discussion: lines 206-218 - need to be relocated to the Results section. The Discussion section needs to discuss not restate the findings of the study. The Discussion section is very weak:
. lack comparisons to findings from Greece, the Mediterranean region and worldwide, 
. lacks discussion of the limitations of the study,
. and lacks discussion of the strengths of the study.

A: Thank you for your suggestions. The content has been adjusted as follows: «In summary, demographic data indicate that PS use prevalence was 30%, with higher intake among males (62%) than females (32%; p < 0.001). Younger participants (18–34 years), those with normal BMI (18.5–24.9 kg/m²), and non-smokers (p = 0.02) reported greater use. PS intake was higher among non-sports professionals (p < 0.001). Fitness enthusiasts and sports professionals were more likely to believe PSs are regulated like medications (p = 0.02 and p = 0.01, respectively)», and relocated to the results section.

Comparison of findings with those of other studies

The following paragraphs have been added:

Our study identified gender, age and BMI as significant predictors of PS use, with higher consumption reported among males, younger adults (18–34 years) and individuals with normal BMI (18.5–24.9 kg/m²). These findings are consistent with previous research, which highlights that PS users are predominantly males and young adults with normal weight. Conversely, a study in the Jazan region observed that 90.8% of female non-athlete gym attendees consumed PS, compared to 77.6% of males . This suggests that cultural and regional factors may influence supplement patterns.

Our data indicates that smoking status influenced PS use, with non-smokers reporting higher usage. Interestingly, participants not employed in sports-related fields showed higher PS consumption. These findings align with research suggesting that non-smokers are generally more inclined to use PSs, likely due to broader health-conscious behaviors. Moreover, supplement use among non-sports professionals may be driven by personal health and fitness goals, emphasizing the multifaceted nature of supplement consumption. However, the existing literature on these associations remains limited, and further investigation is needed to better understand the underlying factors. The participants' most common motivation for PS use was to increase muscle mass, followed by muscle recovery and performance enhancement, which is consistent with findings reported in the literature. However, some studies report gender differences in supplement use motivations. We observed no significant gender-based variation, which aligns with meta-analyses showing minimal differences in resistance training-induced benefits between genders.  Protein powders were the preferred form of supplementation, with many participants consuming them post-workout (55%), and others using them pre- (20%) or peri-workout (19%). These patterns align with evidence supporting post-exercise protein intake for muscle synthesis and recovery, though debates about the optimal timing persist. A notable proportion of participants reported adverse effects such as nausea, dizziness, allergic reactions, and sleep disturbances, reflecting concerns raised by other studies. However these findings may be subject to biases, including self-report and selection bias, which could affect the accuracy and generalizability of reported adverse effects and motivations.. Future research should provide prospective designs, standardized measures, and adjust for potential confounders to strengthen causal inference and reduce bias. Interestingly, many participants believed PSs undergo regulatory processes similar to medications, reflecting misconceptions about supplement safety. This contrasts with literature indicating variable regulatory controls across countries and the absence of stringent oversight in the supplement industry. Half of the respondents engaging in multiple types of exercise believed PSs are beneficial for health, while most participants relied on non-professional sources such as social media and sports coaches for information, reflecting global findings on limited engagement with HCPs for supplementation advice.

 Discussion of the limitations of the study

The following paragraph has been added:

The findings of this study have to be seen in light of some limitations. The description of exercise intensity was based on each respondent’s self-perception, which may not accurately reflect the actual intensity of their exercise practices. The survey relied on self-reported data for PS use, motivations, and health perceptions, which may introduce bias or social desirability bias. Total dietary protein intake was not assessed, which could have influenced participants' protein supplementation choices. Future research should incorporate detailed assessments of both total dietary protein intake and protein types to clarify the relationship between baseline intake and supplementation patterns. Additionally, the study was conducted within a specific cultural context, and cultural differences may affect the generalizability of the findings to other populations. Future research should expand on these findings by incorporating more diverse, and culturally varied samples to validate the results, reduce bias, and explore demographic patterns and motivational factors and health perceptions across different populations and food cultures. Regardless of these limitations, this research provides a foundation for future studies, including randomized controlled trials, that can address these challenges and integrate PS use with safety considerations into the lifestyles of non-professional athletes.

Discussion of the strengths of study

Despite its limitations, this study has several strengths. A major strength is the large sample size (n=1,100), which enhances the reliability of the findings and supports their generalizability within the studied population. However, future investigation should incorporate formal sample size calculations to ensure optimal study design. The current study provides novel insights into PS by examining demographic patterns such as gender, age, and motivational factors among non-professional athletes and general fitness practitioners, with limited evidence available from Greece. By incorporating demographic, behavioral, and attitudinal factors, the study adds depth to existing literature and highlights important trends, such as the reliance on informal information sources and misconceptions about supplement safety. Importantly, this research contributes to public health discussions by identifying areas where educational and regulatory interventions can promote safer and more informed PS practices.

.C: Materials and Methods: the Methods section lacks details on many aspects of the study:
. validation of the questionnaire on the targeted population
. representation of the sample for the physically active Greek population
. and sample size calculation and appropriateness

A: Thank you for this important comment.

The following content has been added for clarification in the Methods section:

The questionnaire was constructed based on gaps identified in previous literature (Knapik et al., 2016 ) and was adapted from previous validated questionnaire (Sánchez et al, 2011) designed to assess patterns and perceptions of protein supplement use. A pilot test was conducted with a sample of 30 individuals from the target population in Greece to ensure clarity and relevance.  The initial draft of the questions was reviewed and edited by non-professional athletes and fitness practitioners.

 Representation of the sample for the physically active Greek population

Thank you for this valuable comment. Our study sample of 1,100 participants was drawn from diverse locations in two major Greek cities (Athens and Thessaloniki), encompassing gyms, athletic organizations, amusement parks, and playing fields. The inclusion criteria ensured participants were non-professional athletes or fitness practitioners who engaged in physical activity for at least six months prior to participation, with exclusions for professional athletes and individuals with significant health issues. Although the sample was large and diverse, we recognize that it may not fully represent the broader physically active population across all regions of Greece, particularly rural areas or informal activity groups.

The following content has been added for clarification in the Study Limitations Section: 

The study was conducted within a specific cultural context, and cultural differences may affect the generalizability of the findings to other populations. Future research should expand on these findings by incorporating more diverse, and culturally varied samples to validate the results, reduce bias, and explore demographic patterns and motivational factors and health perceptions across different populations and food cultures.   

Sample size calculation and appropriateness

We appreciate the comment regarding the sample size calculation and its appropriateness. Our study was designed as a cross-sectional survey, with an initial target of approximately 2,000 distributed questionnaires to achieve a 50% response rate. We obtained 1,100 completed responses from non-professional athletes and fitness practitioners across Athens and Thessaloniki. Although no formal a priori power calculation was conducted, the final sample size of 1,100 participants greatly exceeds the minimum typically required for cross-sectional studies examining prevalence and associations in this field. The large sample size enhances statistical power and allows subgroup analyses, increasing the reliability and generalizability of our findings within the studied population. We acknowledge the absence of a formal sample size calculation as a limitation and recommend its inclusion in future research for optimal study design. The following content has been added for clarification in the Study Strengths Section :  

A major strength is the large sample size (n=1,100), which enhances the reliability of the findings and supports their generalizability within the studied population. However, future investigation should incorporate formal sample size calculations to ensure optimal study design.

C: Conclusions: no p values need to be mentioned in the discussion or conclusion section (line 297). Line 300: long term health effects of what? - this needs to be clarified. 

A: Thank you for your suggestions, the conclusion and implication of the study have been revised as follows: Line 405

This study contributes to the growing body of research on PS consumption among non-professional athletes, a population that has been less extensively studied compared to elite athletes. Our findings highlight key demographic, behavioral, and motivational factors influencing PS use, reinforcing trends observed in previous literature. While PS has recognized benefits the reported side effects among PS users underscore the importance of consumer awareness and regulatory oversight. Despite the wide use of PSs, misconceptions persist regarding their regulation and safety, with many participants relying on non-professional information sources. This study emphasises the need for targeted educational initiatives to improve awareness of safe PS practices among non-professional athletes and fitness practitioners. Regulatory bodies should consider strengthening supplement oversight to ensure product quality and accurate labeling. The findings underline the importance of HCPs in guiding supplement decisions and suggest the value of culturally tailored public health strategies. Future research, including longitudinal studies and randomized controlled trials needs to further assess long-term health effects and optimal use of PS in non-professional athletes. 

C: References: up to date. Needs to be expanded to cover more accurately the literature on this topic. 

A: Thank you for your suggestions. Due to the additions in various parts of the manuscript, current literature has been added.

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have addressed most of my comments.

But still, the footnotes of all tables and figures need to be revised...they are not always accurate as they mention sometimes about p values and there are no p values displayed on the figures for instance, etc. 

Also, extensive English editing is still needed.

Author Response

Dear Reviewer

We would like to thank you for your detailed review, which has contributed to the improvement of our manuscript.

 

C: But still, the footnotes of all tables and figures need to be revised...they are not always accurate as they mention sometimes about p values and there are no p values displayed on the figures for instance, etc. 

A: We have revisited the captions and footnotes in all tables and figures to improve clarity and accuracy.

 

C: Also, extensive English editing is still needed.

A: We have revisited the manuscript text to improve our use of English.