November 03, 2020 5 min read
Hello #MomentumLovers! I'm Dr. Drai a board-certified OBGYN, sexual health expert, and founder of Momentum Intimacy. Through my FDA-approved condom & lubricant line called Momentum, I help people improve their intimacy and have a more satisfying sex life.
You are probably wondering why I am writing about glycerin, right? Our Momentum water-based lubricant contains it. Let us start from the beginning. Glycerol, the chemical name for trihydric alcohol (C3H5(OH)3), and glycerine are synonymous terms; glycerol generally refers to the chemical entity and glycerin refers to the industrial forms and uses (1). Glycerin, a natural compound derived from animal fats or vegetable oils, is a sweet, colorless, odorless, and viscous liquid. It has been reported to be one of the most valuable and versatile chemical materials known (2). It is a versatile ingredient that has been used in everything from food all the way to pharmaceuticals. It has also been used in water-based personal lubricants for women and men because it is the primary factor determining osmolality and serves as a humectant and emollient (3), but its use in this regard has been associated with much debate; largely because of concerns raised regarding glycerin and its theoretical association with an increase in vaginal infections. Well, this is where I come in, I will provide an overview of the data available, some current applications of glycerin, and finally, dispel the myth that glycerin is an unsafe ingredient in personal lubricants.
According to the United States Food and Drug Administration (FDA), glycerin is “generally recognized as safe when used in accordance with good manufacturing practice” (4). Glycerin is occasionally used in processed foods to sweeten them, to thicken them, to control their moisture level, to preserve them, or to stabilize them if they contain a mix of water and oil. Contrary to popular belief, glycerin is an alcohol, not a sugar (5), and therefore, per The International Food Information Council Foundation, it does not significantly promote insulin secretion when it is consumed, keeping the body’s blood glucose levels lower than the levels produced by eating other types of carbohydrate, including sugars (6).
Because glycerin does not promote insulin secretion which would mean an increase in the body’s blood sugar, this is where the case for glycerin causing yeast infections becomes weak. Yeast infections are caused by several things including, antibiotics which change the flora of the genitourinary tract, stress, fatigue, lack of hygiene during sex, or even wearing a wet swimsuit for too long. While yes, putting sugar on your vagina can cause a yeast infection, putting glycerin there does not, because, again, glycerin is not a sugar.
Interestingly, glycerin has mild antibacterial and antiviral effects and has been approved by the FDA in products developed for wound care (7). Glycerin has also been safely used in skincare products (orally administered glycerol fully corrected the reduced skin elasticity in mice with reduced skin elasticity! (8), cosmetic products (9), soaps, essential oils, shampoos, and even by blood banks to preserve red blood cells prior to freezing (10). It has also been used as an enema (11), as an ingredient in electronic cigarettes (12), and curiously, by makeup artists in the film industry to stimulate droplets of sweat (13).
There are a few studies examining the association of glycerin with vaginal infections, but all are small studies and some report conflicting data; in general, it is not recommended to make clinical practice decisions based on results of small studies. I will provide a summary of available studies based on a PubMed.gov search of “glycerin”, “glycerol”, and “vaginal infections”. One small study of 39 women reported that the use of personal lubricant the day before testing was associated with bacterial vaginosis. However, the type of lubricant and its ingredients were not reported, bacterial vaginosis was found by Gram stain as opposed to symptoms reported, and finally, study investigators report that “the effect of glycerin on protective lactic acid-producing bacteria is not known” (14). Conversely, in another small randomized, double-blind study of 36 women who self-administered intravaginal gels containing glycerol monolaurate, glycerol monolaurate inhibited Candida (yeast) and Gardnerella vaginalis (the organism that causes bacterial vaginosis) but not Lactobacillus (an organism in the normal flora of women that protects the genital tract) (15). The largest study was published in 2013 in the Journal of Obstetrics & Gynecology (16) and enrolled 141 women, also considered a small study. In this study, intravaginal insertion of petroleum jelly was associated with an increased risk of bacterial vaginosis even when study investigators accounted for intravaginal washing, age, race, HIV status, vaginal exposure to semen over the past month, the number of male sexual partners over the past month, and HSV-2 status. Importantly, study investigators did not find an increased risk for bacterial vaginosis among women reporting intravaginal insertion of commercial lubricants or oils. Additionally, while testing positive for Candida colonization was associated with intravaginal insertion of oil, there was no increased risk for Candida colonization among women reporting intravaginal insertion of commercial lubricants or petroleum jelly (16).
In summary, while these studies were small, the largest study of 141 women did not find an association between intravaginal insertion of commercial lubricants and bacterial vaginosis or Candida colonization (16). As such, while most decisions are personal and driven by prior experience, we do not have any published data to definitively link commercial lubricant use with vaginal infections that we know can be caused under several circumstances. Glycerin is a common ingredient in personal lubricants- it makes the wetness and slippery feeling last longer. I hope I have convinced you that glycerin is safe to use in personal lubricants and have put an end to The Great Glycerin Debate when it comes to long, satisfying, and pleasurable sex.
1. Hilditch TP. Production and Uses of Glycerine. Nature 1953;172:1066-1067.
2. Arif M, Abd El-Hack ME, Hayat Z, Sohail S, Saeed M, Alagawany M. The beneficial uses of glycerin as an alternative energy source in poultry diets. World's Poultry Science Journal 2017;73:136-144.
3. Edwards D, Panay N. Treating vulvovaginal atrophy/genitourinary syndrome of menopause: how important is vaginal lubricant and moisturizer composition? Climacteric 2016;19:151-161.
4. US Food and Drug Administration Code of Federal Regulartions Title 21, https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=182.1320&SearchTerm=glycerin, accessed 7/29/2020.
5. Freeman J, Hayes C. “Low-Carbohydrate” Food Facts and Fallacies. Diabetes Spectrum 2004;17:137-140.
6. International Food Information Council Foundation https://foodinsight.org/what-is-glycerin/#:~:text=Glycerin%20is%20a%20type%20of,a%20sugar%20alcohol%2C%20or%20polyol.&text=Glycerin%20occurs%20naturally%20in%20fermented,of%20yeast%2C%20sugar%20or%20starch, accessed 7/29/2020.
7. Stout EI, McKessor A. Glycerin-Based Hydrogel for Infection Control. Adv Wound Care (New Rochelle) 2012;1:48-51.
8. Hara M, Verkman AS. Glycerol replacement corrects defective skin hydration, elasticity, and barrier function in aquaporin-3-deficient mice. Proceedings of the National Academy of Sciences 2003;100:7360-7365.
9. Becker LC, Bergfeld WF, Belsito DV et al. Safety Assessment of Glycerin as Used in Cosmetics. International Journal of Toxicology 2019;38:6S-22S.
10. Chaudhari CN. Frozen Red Blood Cells in Transfusion. Med J Armed Forces India 2009;65:55-58.
11. Bertani E, Chiappa A, Biffi R et al. Comparison of oral polyethylene glycol plus a large volume glycerine enema with a large volume glycerine enema alone in patients undergoing colorectal surgery for malignancy: a randomized clinical trial. Colorectal Disease 2011;13:e327-e334.
12. Chun LF, Moazed F, Calfee CS, Matthay MA, Gotts JE. Pulmonary toxicity of e-cigarettes. Am J Physiol Lung Cell Mol Physiol 2017;313:L193-L206.
13. How do make-up artists create sweat in the movies? https://www.denofgeek.com/movies/how-do-make-up-artists-create-sweat-in-the-movies/, accessed 7/29/2020.
14. Brotman R, Ravel J, Cone R, Zenilman J. Rapid fluctuation of the vaginal microbiota measured by Gram stain analysis. Sexually Transmitted Infections 2010;86:297-302.
15. Strandberg KL, Peterson ML, Lin Y-C, Pack MC, Chase DJ, Schlievert PM. Glycerol Monolaurate Inhibits Candida and Gardnerella vaginalis In Vitro and In Vivo but Not Lactobacillus. Antimicrobial Agents and Chemotherapy 2010;54:597-601.
16. Brown JM, Hess KL, Brown S, Murphy C, Waldman AL, Hezareh M. Intravaginal Practices and Risk of Bacterial Vaginosis and Candidiasis Infection Among a Cohort of Women in the United States. Obstetrics & Gynecology 2013;121.
Thank you for reading this #MomentumLovers! As always...I'm Dr. Drai a board-certified OBGYN, sexual health expert, and founder of Momentum Intimacy. Through my FDA-approved condom & lubricant line called Momentum, I help people improve their intimacy and have a more satisfying sex life. If you are ready to level up your love life, use the coupon code MeTime for 20% off at FeelTheMoment.com.
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