This article is an adapted, updated and modified excerpt from a Well + Good article that featured OB/GYN Gunvor Ekman Ordeberg, MD, PhD. It is meant to be an educational document based on the opinion of Dr. Ordeberg to inform the public and offer suggestions for more research.
Penetrative sex is one of the few situations in life where the more slippery it is, typically the better. While a vagina can create an ample dose of wetness on its own, adding in a personal lubricant can instantly level things up - and keep it that way, however long you might like. But exactly which lube you choose matters not only for its efficacy and glide, but also for its health implications, given its close contact with the vagina. One option worth understanding better is the silicone-based lubricant. Some evidence suggests that silicone-based products may be more effective than water-based ones for vaginal dryness and dyspareunia,1 and a four-week randomized study found that a well-formulated water-based lubricant and a well-formulated silicone-based lubricant both left the vaginal and vulvar microbiome stable.2
As a quick lube refresher, silicone-based lubricant is one of the three common categories of lube, alongside water-based and oil-based formulas. But while certain folks might prefer one of the latter two options - for example, opting for water-based options for their compatibility with silicone sex toys, or oil-based to reap the soothing qualities of sunflower oil or even CBD - silicone-based lubes differ in one respect that bears directly on vaginal health. Water-based lubricants must contain preservatives to prevent microbial growth, and those preservatives can cause irritation and sensitization in some individuals.3 A water-free silicone formulation does not require that preservative system.
How different personal lubricants can affect the health of the vagina
Consider first that a happy, pH-balanced vagina of a woman of childbearing age is somewhat acidic, anywhere from a 3.8 to a 5.0 pH.4 (As a reminder, the pH scale goes from a super-acidic 0 to a highly basic 14.) When your vagina’s pH is unbalanced in either direction, as Love Wellness founder Lo Bosworth previously told Well+Good, “you’re having an issue with your vaginal microbiome,” which can, in turn, allow for unhealthy bacterial growth and infection. And the same is true for the reverse: Messing with that microbiome can cause a pH imbalance - which can also lead to infection.
Dr. Michael Krychman, board certified OBGYN, notes that water-based products can have varying osmolalities as well as additives such as bactericides, spermicides, warming, flavors and preservatives that have the ability to change the vaginal pH and disrupt the homeostasis of the lactobacillus or good bacteria flourishing in the vagina. He notes that, “All of these added ingredients can act as disrupters of the vaginal biome.” Krychman also notes that, “Silicone lubricants do not contain water and will not impact the vaginal microbiome.”3,5
Not to mention, the pH of a water-based lubricant itself can mess with a balanced vagina’s pH (regardless of the bacteria-killing actions of its preservatives). And with a silicone-based lubricant, you simply don’t run that risk. “Because silicone-based lubricants, again, do not contain any water, they have no pH value and won’t interfere with the vaginal pH,” says Dr. Ordeberg.
Another upside: Since silicone-based lubricants dissipate slowly and stay slippery for a longer time than water-based lubricants, they’re typically free of the additives used to boost glide in their water-based counterparts - like glycerin, glycerol, and propylene glycol. “These substances, as well as sweeteners and flavors, can increase something called osmolality, which is the measurement of how much solvent[solute] is dissolved in a formula,” says gynecologist and sexual-wellness expert Christie Cobb, MD. When osmolality of a lubricant exceeds 380 mOsm/kg - the upper limit recommended by the World Health Organization (WHO) to minimize the risk of epithelial damage - you risk jeopardizing vaginal cells.3 For reference, WHO puts the normal osmolality of vaginal secretions at 260–290 mOsm/kg.3
How? If you can recall learning about osmosis in science class, you might remember that water molecules tend to move across permeable membranes (like the vaginal lining, in this case) from the less-concentrated solution to the more-concentrated one, diluting it. So, a high-osmolality (aka very concentrated) lubricant could suck some of the moisture out of your vaginal cells, leading to epithelial tissue damage. “That can cause irritation and make you more susceptible to sexually transmitted infections,” says Dr. Cobb.
While not all water-based lubricants have a high osmolality (this number isn’t often reported on the bottle, but you can find a list of common ones in the above WHO report), silicone-based lubricants evade this issue entirely. Again, they don’t contain any water, so there’s no risk of water molecules crossing the vaginal membrane. Hyperosmolar lubricants also may increase the risk of bacterial vaginosis, which nobody wants.6
All of that said, you definitely don’t want to use a silicone-based lubricant if you or a partner is allergic to silicone or are pairing the lube with a silicone sex toy, as it can degrade the toy over time. In these cases, you’d be better off with a water-based lubricant formulated with a matching pH to the vagina (check the packaging for the number or the words “pH-balancing”) and only natural preservatives, says Dr. Cobb.
And if you already have an oil- or water-based lube that you totally love? If you’re not experiencing vaginal dryness, repeat infections (yeast or bacterial vaginosis), or any kind of irritation, you may be fine sticking with it. Though, your best bet is not to let either lube linger in the vagina or on the vulva post-sex, just to minimize your chances of any potential pH disruption. According to Dr. Cobb, different lubes can certainly work differently in different people, so it’s not a bad idea to try a few until you find your reliable winner.
Ingredients to avoid in any kind of lubricant to maintain vaginal health
No matter the base of the lubricant you choose (water, oil, or silicone), it’s wise to steer clear of any kind of fragrance. “Perfume inside the vagina is like vaginal suicide,” says Dr. Ordeberg. “Many perfumes contain known allergens and alcohol, all of which may cause irritation and can potentially dry out the skin.”
It’s also a good call to avoid any product containing the spermicide and microbicide nonoxynol-9, which has been shown to cause rapid exfoliation of genital epithelial cells and to alter the vaginal microbiome.5
Most health care professionals also strongly suggest only using a lubricant that’s been cleared by the Food and Drug Administration (FDA). “Personal lubricants actually have to be approved as medical devices by the FDA, which is a different [and more stringent] process than cosmetics,” says Dr. Cobb. So, essentially, when you’re buying an FDA-cleared lubricant, you can be sure its benefits outweigh any known risks.
References
- Marino, J. L.; McNamara, H. C.; Hickey, M. Managing Menopausal Symptoms after Cancer: An Evidence-Based Approach for Primary Care. Medical Journal of Australia 2018, 208 (3), 127–132. https://doi.org/10.5694/mja17.00693
- Freixas-Coutin, J. A.; Seo, J.; Su, L.; Hood, S. Longitudinal Analysis of Vulvovaginal Bacteriome Following Use of Water- and Silicone-Based Personal Lubricants: Stability, Spatial Specificity, and Clinical Implications. Microorganisms 2025, 14 (1), 82. https://doi.org/10.3390/microorganisms14010082
- World Health Organization (2012). Use and procurement of additional lubricants for male and female condoms: WHO/UNFPA/FHI360: advisory note. World Health Organization. https://iris.who.int/handle/10665/76580
- Lin, Y.-P.; Chen, W.-C.; Cheng, C.-M.; Shen, C.-J. Vaginal pH Value for Clinical Diagnosis and Treatment of Common Vaginitis. Diagnostics 2021, 11 (11), 1996. https://doi.org/10.3390/diagnostics11111996
- Edwards, D.; Panay, N. Treating Vulvovaginal Atrophy/Genitourinary Syndrome of Menopause: How Important Is Vaginal Lubricant and Moisturizer Composition? Climacteric 2015, 19 (2), 151–161. https://doi.org/10.3109/13697137.2015.1124259
- Lorenz, T.; Angeletti, P. (158) Hyperosmolar Lubricants Increase Risk of Bacterial Vaginosis and Lower Sexual Arousal in Sexually Active Women. The Journal of Sexual Medicine, Volume 23, Issue Supplement_3, March 2026, qdag063.147. https://doi.org/10.1093/jsxmed/qdag063.147
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