Water-based lubricants are safe for vaginal use, a UCI study shows

June 05, 2023

Water-based lubricants that help postmenopausal women relieve pain associated with sexual intercourse do not appear to change or harm the vaginal microbiome, according to a new UCI study.

The randomized study of pre- and postmenopausal women found that “the intravaginal microenvironment was not affected by the [water-based] lubricant in the long-term,” UCI Health gynecologist Dr. Michael L. Krychman, the study’s lead author, said at the American College of Obstetrics and Gynecology’s annual meeting in Baltimore, Md.

Estrogen production drops as much as 95% during menopause, leading up to 57% of postmenopausal women to experience vaginal dryness and a thinning of the vaginal walls.

Lubricants recommended for painful genitourinary syndrome 

Called genitourinary syndrome of menopause (GSM), this condition may result in pain during sexual intercourse that is so severe in some women it can dramatically affect their quality of life, according to the National Institute on Aging. Among a number of treatment options, gynecologists often recommend the use of over-the-counter lubricants during sex.

Water-based lubricants that preserve the vagina’s natural pH or acidic levels of 4.5 are considered best for optimal health. But their long-term effect on the vulvovaginal microbiome, especially in women experiencing mild to moderate dryness, are understudied and underappreciated, said Krychman, a volunteer professor of Obstetrics and Gynecology at the UCI School of Medicine and director of Ann’s Clinic at UCI Health, whose conference remarks appeared in Healio, a health news website.

Women followed for four weeks

The study, published in the journal Obstetrics & Gynecology, followed 174 women ages 18 to 65 who reported vaginal dryness and dyspareunia, or pain during sex. Each was assigned to use a water-based lubricant during intercourse at least once a week for four weeks.

Researchers used swabs to test vaginal moisture and pH levels before as well as two hours, 24 hours and four weeks after lubricant use to measure the vulvovaginal microbiome. Vaginal pH levels increased after application of lubricants but returned to previous levels within about a day after use.

Larger, diverse population needed for more study

“These lubricants can be used not only to relieve … vaginal dryness and dyspareunia, but to enhance overall sexual satisfaction regardless of menopausal status,” the study concluded.

Krychman said the effects of lubricants on the vaginal microbiome need additional study in a larger, more diverse patient population.

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About UCI Health

UCI Health is the clinical enterprise of the University of California, Irvine, and the only academic health system in Orange County. Patients can access UCI Health at primary and specialty care offices across Orange County and at its main campus, UCI Medical Center in Orange, Calif. The 459-bed, acute care hospital, listed among America’s Best Hospitals by U.S. News & World Report for 21 consecutive years, provides tertiary and quaternary care, ambulatory and specialty medical clinics, behavioral health and rehabilitation services. UCI Medical Center is home to Orange County’s only National Cancer Institute-designated comprehensive cancer center, high-risk perinatal/neonatal program and American College of Surgeons-verified Level I adult and Level II pediatric trauma center and regional burn center. UCI Health serves a region of nearly 4 million people in Orange County, western Riverside County and southeast Los Angeles County. Follow us on Facebook, Instagram, LinkedIn and Twitter.