Are Sexual Lubricants Safe?

Previously, I’ve extolled commercial sexual lubricants as the slippery secret of sensational sex. Why the endorsement? In both women and men, lube enhances skin sensitivity to erotic touch. Many women of all ages don’t self-lubricate sufficiently for comfortable intercourse. And many post-menopausal women suffer chronic vaginal dryness. As a result, many sexologists encourage couples of all ages to use lube every time.

But now I must temper my enthusiasm. Recent research suggests that, in frequent users, sexual lubricants damage genital skin cells and may increase risk of sexually transmitted infections (STIs). I hasten to add that, for many lovers, lube benefits outweigh any risks. But the risks appear real and couples should understand them—and use lube with not just legs, but also eyes open.

Risk in High Osmolality?

Over the past 30 years, sexual lubricants have become quite popular. In the U.S. alone, they are a $200 million a year industry. A majority of couples have tried them. One-quarter of couples have used lube in the past month. And a broad consensus of women say they make intercourse more comfortable and enjoyable.

The most popular sexual lubricants—among them, Astroglide and K-Y Warming Jelly— are water-based, meaning that water is their main ingredient. In addition, these lubes contain glycerin and propylene glycol that slow the water’s evaporation and make the products slipperier than saliva.

But those other constituents also increase “osmolality,” a measure of the molecular concentration of ingredients. Most sexual lubricants have osmolalites substantially greater than the cells to which they are applied (hyperosmolality). When high-osmolality products come in contact with lower-osmolality genital or rectal cells, the cells lose water and shrivel up like grapes turning into raisins. And that may cause problems:

• Portuguese researchers exposed vaginal cells to either commercial high-osmolality lubricants or to a lubricant they formulated that had the same osmolality (iso-osmolality) as the cells. The high-osmolality lubes caused cell damage that might increase risk of STIs.

• The vagina contains a broad array of micro-organisms that help keep it healthy. University of Pittsburgh researchers found that high-osmolality lubricants kill some of these micro-organisms, possibly make the vagina more susceptible to STIs.

• Johns Hopkins researchers replicated the Portuguese study using rectal cells. The commercial lube caused greater cell damage, prompting the researchers to conclude that they might increase risk of HIV transmission.

• As part of an ongoing study, UCLA researchers surveyed adults about receptive anal intercourse (RAI) and lubricant use. Recalling the month before being surveyed, one-third of the participants reported frequent RAI and consistent use of lube.  Compared with couples who used lube infrequently or not at all, the frequent RAI-frequent lube users had three times the risk of a sexually transmitted infection—3 percent vs. 10 percent.

One of the Johns Hopkins researchers, biophysicist Richard Cone, Ph.D., advocates reducing the high-osmolality of lubricants, “Virtually all sex lubricants need to be reformulated.”

On the Other Hand

The problem with the studies just cited is that most studied cells in the laboratory, not people in the real world. Laboratory findings may be statistically significant, and therefore qualify for publication, but not really mean anything beyond the test tubes.

The one real-word study focused on couples who engaged in frequent anal intercourse, but that group represents only a small minority of the general population of lovers.

Meanwhile, Indiana University researchers gave 2,453 women one of several lubricants and asked them to keep a daily sex diary for five weeks. Compared with controls who did not use any lube, those who did reported substantially greater sexual pleasure and satisfaction with fewer genital complaints and no increased risk of STIs.

The Case for Saliva

The research to date raises questions about lube safety, but the only real-world study pointing to an increased risk of STIs involves couples who have frequent anal intercourse. For everyone else, there is no documentation of any increased risk, and some evidence of less risk. A confusing situation.

One reasonable response to the uncertainty would be to use the lube that’s closest in osmolality to genital cells. That product is Good Clean Love, available at Wallgreens and Target, or on their Web sites.

Another would be to use saliva, Nature’s own sex lubricant. Saliva is always available and it’s free. But saliva is not as slippery as commercial lubes and it dries quickly.

Meanwhile, a growing literature shows that in couple lovemaking, the key to women’s orgasms is not vaginal intercourse, but gentle, extended, cunnilingus—men providing oral sex for women. Intercourse can feel wonderful and many couples revel in its special closeness. But no matter how long intercourse lasts or how large the penis, the old in-out doesn’t provide much clitoral stimulations. As a result, among couples who equate “sex” and “intercourse,” men have orgasms around 95 percent of the time, but women’s rate is only around 50 percent.  But when men provide gentle, extended oral, women’s rates of orgasm increase to around 90 percent.

Cunnilingus automatically lubricates the vagina with saliva. So what if it isn’t as slippery as a commercial lube? During cunnlingus the man’s erection doesn’t enter the woman’s vagina, so friction and irritation are not issues. And so what if saliva dries faster than lubes? If the man provides extended cunnilingus, he’s constantly refreshing the saliva on the vulva and clitoris, so drying isn’t an issue.

Lubes may or may not do more harm than good. But lovers can easily skirt this controversy—and increase women’s likelihood of orgasm—by incorporating more cunnilingus into lovemaking.


Cunha, A.R. et al. “Characterization of Commercially Available Vaginal Lubricants: A Safety Perspective,” Pharmaceutics (2014) 6:530.

Dezzutti C.S. et al. “Is Wetter Better? An Evaluation of Over-the-Counter Personal Lubricants for Safety and Anti-HIV-1 Activity,” PLoS ONE (2012) 7: e48328. doi:10.1371/journal.pone.0048328.

Fuchs, E.J. et al. “Hyperosmolar Sexual Lubricant Causes Epithelial Damage in the Distal Colon: Potential Implication for HIV Transmission,” Journal of Infectious Diseases (2007) 195:703.

Gorbach, P.M. et al. “The Slippery Slope: Lubricant Use and Rectal Sexually Transmitted Infections: A Newly Identified Risk,” Sexually Transmitted Diseases (2012) 39:59.

Richters, J. et al. “Sexual Practices at Last Heterosexual Encounter and Occurrence of Orgasm in a National Survey,” Journal of Sex Research (2006) 43:217.

Wade, L.D. et al. “The Incidental Orgasm: The Presence of Clitoral Knowledge and the Absence of Orgasm for Women,” Women and Health (2005) 42:117.

Wolf. L.K. “Studies Raise Questions about Safety of Personal Lubricants,” Chemical and Engineering News (Dec. 10, 2012) 90:50:46.


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