A study was done by Johns Hopkins biophysicists to investigate several different personal lubricants currently available on the market, and to compare their effect on genital tissues and susceptibility to infections. The researchers took the path of analyzing osmolarity of the products. Osmolarity describes the concentration of chemical ingredients within a cell and products with high osmolarity have adverse effects on genital and rectal tissue, including the increased risk of genital herpes infections, at least in animal testing. Lubricants with petrochemical bases expose the cells to this high osmolarity which then causes damage to vaginal and anal tissue, thus allowing it to become more susceptible to infections. In this comparison study, a product called “Good Clean Love” had the lowest osmolarity, of 270 which is lower than extracellular body fluid and semen. Petrochemical-based lubricants on the other hand, with higher osmolarity (ex/ Astroglide 6,300; KY Jelly 2,500, KY Warming Jelly 10,300) can increase the risk of bacterial vaginosos (BV) by 12 to 14 times.
Sources: Chemical and Engineering News 2013;90(50)
Commentary: Personal lubricants have been seen as potential deliveries of microbicide components in the gel that could protect individuals from HIV. Unfortunately, the promise of nonoxynol-9 in vaginal gels actually failed to show protection of women from HIV and in 2002, it actually increased the risk of HIV infection. It turns out that nonoxynol-9 is not only an effective spermicide, it also damages the cells lining the vagina and rectum and this then alters the potential inherent protective aspect of the mucosal lining of the vagina. Nonoxynol-9 is still used on some condoms today. Safety issues regarding spermicides and personal lubricant ingredients led to the investigations of the scientists at Johns Hopkins and they then proceeded to investigate the osmolarity of lubricants and how that may be related to tissue injury. Previous studies have also investigated this. Hyperosmolar rectally applied personal lubricants was associated with greater epithelial denudation (cell injury) and mucosal permeability in a 2007 study. These changes are thought to be associated with increased risk of HIV transmission. Lubricant use was a strong predictor of BV in another study.
K-Y Warming Jelly has an osmolality more than 30 times the body’s own fluid and increased herpes transmission more than 9 times when compared to no lubricant administered in an animal study. In 2007, another Johns Hopkins researcher demonstrated in a human study that ID Glide, which is a hyperosmolar lubricant similar to Astroglide and K-Y Jelly, caused significant damage to the rectal tissue. But, recently researchers observed that while hyperosmolar lubricants did damage normal rectal and cervical cells, they did not increase HIV infection. There have been other studies that have reported no cell toxicity from hyperosmolar lubricants as well, including one using K-Y Warming Jelly, with the active microbicide, glycerol monolaurate.
Conventional, non organic lubricants contain a variety of ingredients including glycerin and chlorhexidine. Chlorhexidine is a broad spectrum microbicide (kills bacteria, including the dominant protective vaginal bacteria, lactobacilli species, which competitively inhibit infection causing bacteria), which may cause toxic effects to mucosal tissues. Glycerin is thought to increase osmolarity while its effects on the protective lactic acid producing lactobacilli species is not known. It seems wise to use personal lubricants that do not contain petrochemicals, parabens, glycerin or nonoxynol-9. While nonoxynol-9 (N-9) is the active ingredient used in all spermicides in the U.S. and contraceptive effectiveness with diaphragms and condoms and the FemCap is more effective with this spermicide, the CDC and the World Health Organization seem to agree on the following:
1) N-9 is a safe, effective contraceptive option for women at low risk of HIV/STIs who do not use the product more than once per day.
2) N-9 should not be used to prevent HIV/STIs
3) N-9 should not be used rectally