Previous Article in Journal
Properties and Pharmacology of Scorpion Toxins and Their Biotechnological Potential in Agriculture and Medicine
 
 
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
This is an early access version, the complete PDF, HTML, and XML versions will be available soon.
Article

Computational Modelling Suggests Bacteriostatic Saline Does Not Reverse Botulinum Toxin-Induced Brow Ptosis

1
Research and Innovation Hub, Innovation Aesthetics, London WC2H 9JQ, UK
2
The Ottawa Skin Clinic/Project Skin MD Ottawa, Ottawa, ON K1K 2Z7, Canada
3
The Skin Address, Aesthetic Dermatology Practice, Bangalore 560080, India
4
Shahid Suhrawardy Medical College & Hospital, Dhaka 1207, Bangladesh
5
Department of Ophthalmology, University of British Columbia, Vancouver, BC V5Z 4E1, Canada
6
Carruthers Cosmetics, Vancouver, BC V5Z 4E1, Canada
*
Author to whom correspondence should be addressed.
Toxins 2025, 17(10), 498; https://doi.org/10.3390/toxins17100498
Submission received: 29 July 2025 / Revised: 2 October 2025 / Accepted: 4 October 2025 / Published: 7 October 2025
(This article belongs to the Section Bacterial Toxins)

Abstract

Anecdotal reports have recently circulated suggesting that intramuscular injection of bacteriostatic saline (BS)—which contains benzyl alcohol (BnOH)—can reverse botulinum toxin type A (BoNTA)-induced brow ptosis. Given the well-established intracellular persistence of BoNTA’s light chain and its irreversible cleavage of SNAP-25, such rapid functional recovery challenges existing pharmacological understanding. This study employed high-resolution pharmacokinetic/pharmacodynamic (PK/PD) modelling using the AesthetiSim™ platform to systematically evaluate this hypothesis. A total of 30,000 virtual patients were randomized to receive BoNTA alone, BoNTA followed by BS injection, or BoNTA followed by normal saline (NS) at Day 7. The model incorporated BoNTA diffusion, internalization, SNAP-25 cleavage, neuromuscular output, and transient BS effects on membrane permeability and endosomal trafficking. Simulated recovery trajectories were tracked over 90 days. The primary outcome, time to 80% restoration of baseline frontalis muscle force (T80), averaged 42.0 days in the BoNTA-only group and 35.5 days in the BS group (Δ = −6.5 days; p < 0.001). Only 13.9% of BS-treated patients reached the T80 threshold by Day 30. Partial reactivation (T30) occurred earlier with BS (21.8 ± 5.3 days vs. 27.3 ± 4.9 days), and the area under the effect curve (AUEC) was increased by 9.7%, reflecting higher overall muscle function over time. In molecular simulations, BnOH produced a minor rightward shift in the BoNTA–SNAP-25 dissociation curve, but receptor occupancy remained above 90% at therapeutic toxin concentrations, suggesting no meaningful impairment of binding affinity. A global Sobol sensitivity analysis demonstrated that the primary driver of recovery kinetics was intracellular LC degradation (49% of T80 variance), while BS-modulated extracellular parameters collectively contributed less than 20%. These findings indicate that BS does not reverse the molecular action of BoNTA but may transiently influence recovery kinetics via non-receptor-mediated pathways such as increased membrane permeability or altered vesicular trafficking. The magnitude and variability of this effect do not support the notion of a true pharmacologic reversal. Instead, these results emphasize the need for mechanistic scrutiny when evaluating rapid-reversal claims, particularly those propagated through anecdotal or social media channels without supporting biological plausibility.
Keywords: Botulinum toxin; brow ptosis; bacteriostatic saline; benzyl alcohol; pharmacokinetics; pharmacodynamics; neuromodulator; simulation; SNAP-25; aesthetic medicine Botulinum toxin; brow ptosis; bacteriostatic saline; benzyl alcohol; pharmacokinetics; pharmacodynamics; neuromodulator; simulation; SNAP-25; aesthetic medicine

Share and Cite

MDPI and ACS Style

Rahman, E.; Michon, A.; Rao, P.; Sharif, A.Q.M.O.; Webb, W.R.; Carruthers, J.D.A. Computational Modelling Suggests Bacteriostatic Saline Does Not Reverse Botulinum Toxin-Induced Brow Ptosis. Toxins 2025, 17, 498. https://doi.org/10.3390/toxins17100498

AMA Style

Rahman E, Michon A, Rao P, Sharif AQMO, Webb WR, Carruthers JDA. Computational Modelling Suggests Bacteriostatic Saline Does Not Reverse Botulinum Toxin-Induced Brow Ptosis. Toxins. 2025; 17(10):498. https://doi.org/10.3390/toxins17100498

Chicago/Turabian Style

Rahman, Eqram, Alain Michon, Parinitha Rao, A. Q. M. Omar Sharif, William Richard Webb, and Jean D. A. Carruthers. 2025. "Computational Modelling Suggests Bacteriostatic Saline Does Not Reverse Botulinum Toxin-Induced Brow Ptosis" Toxins 17, no. 10: 498. https://doi.org/10.3390/toxins17100498

APA Style

Rahman, E., Michon, A., Rao, P., Sharif, A. Q. M. O., Webb, W. R., & Carruthers, J. D. A. (2025). Computational Modelling Suggests Bacteriostatic Saline Does Not Reverse Botulinum Toxin-Induced Brow Ptosis. Toxins, 17(10), 498. https://doi.org/10.3390/toxins17100498

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop