|Jmol-3D images||Image 1
|Molar mass||616.82 g mol−1|
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Nonoxynol-9, sometimes abbreviated as N-9, is an organic compound that is used as a surfactant. It is a member of the nonoxynol family of nonionic surfactants. N-9 and related compounds are ingredients in various cleaning and cosmetic products. It is widely used in contraceptives for its spermicidal properties.
As a spermicide, it attacks the acrosomal membranes of the sperm, causing the sperm to be immobilized. Nonoxynol-9 is the active ingredient in most spermicidal creams, jellies, foams, gel, film, and suppositories.
A 2004 study found that over a six-month period, the typical-use failure rates for five nonoxynol-9 vaginal contraceptives (film, suppository, and gels at three different concentrations) ranged from 10% to 20%.
Many models of condoms are lubricated with solutions containing nonoxynol-9. In this role, it has been promoted as a backup method for avoiding pregnancy and a microbicide for sexually transmitted diseases in the event of condom failure. However, the 2001 WHO / CONRAD Technical Consultation on Nonoxynol-9 concluded that 
- There is no published scientific evidence that N-9-lubricated condoms provide any additional protection against pregnancy or STDs compared with condoms lubricated with other products. Since adverse effects due to the addition of N-9 to condoms cannot be excluded, such condoms should no longer be promoted. However, it is better to use N-9-lubricated condoms than no condoms.
Compared to regular lubricated condoms, condoms containing nonoxynol-9 present another disadvantage — they have a shorter shelf life.
Almost all brands of diaphragm jelly contain nonoxynol-9 as the active ingredient. This jelly may also be used for a cervical cap. Most contraceptive sponges contain nonoxynol-9 as an active ingredient.
Nonoxynol-9 is sometimes included in shaving creams for its properties as a nonionic surfactant; it helps break down skin oils that normally protect hair from moisture, so that they become wet and, hence, softer and easier to shave. Gillette formerly used nonoxynol-9 for this purpose in its Foamy products, but has discontinued the practice.
Nonoxynol-9 is also found in Bengay Vanishing Scent as an inactive ingredient.
Poison ivy creams
Nonoxynol-9 is also found in Zanfel poison ivy cream. It effectively helps to break up the oil urushiol that causes the rash.
From 1996 to 2000, a UN-sponsored study conducted in several locations in Africa followed nearly 1,000 sex workers who used nonoxynol-9 gels or a placebo. The HIV infection rate among those using nonoxynol-9 was about 50% higher than those who used the placebo; those using nonoxynol-9 also had a higher incidence of vaginal lesions, which may have contributed to this increased risk. Whereas these results may not be directly applicable to lower-frequency use, these findings combined with lack of any demonstrated HIV-prevention benefit from nonoxynol-9 use have led most major health agencies to recommend that it no longer be used by women at high risk of HIV infection. The WHO further notes that "Nonoxynol-9 offers no protection against sexually transmitted infections such as gonorrhoea, chlamydia."
Regular use of nonoxynol-9 appears also to increase the risk of infection with sexually transmitted human papillomaviruses (HPVs) that can cause cervical cancer. In one of the studies, researchers at the National Cancer Institute also reported that the increased likelihood of HPV infection caused by N-9 was mitigated through the use of carrageenan-based lubricants mixed 1:1 with N-9. Two consumer products containing carrageenan, Divine 9 and BIOglide, prevented detectable HPV infection in the study.
- Elizabeth G. Raymond, Pai Lien Chen, Joanne Luoto, for the Spermicide Trial Group. "Contraceptive Effectiveness and Safety of Five Nonoxynol-9 Spermicides: A Randomized Trial" Obstetrics & Gynecology. 2004; 103:430-439. available online
- Marais D, Carrara H, Kay P, Ramjee G, Allan B, Williamson AL. The impact of the use of COL-1492, a nonoxynol-9 vaginal gel, on the presence of cervical human papillomavirus in female sex workers. Virus Res. 2006 Nov;121(2):220-2. Epub 2006 Jul 24. PMID 16860426
- Roberts, Jeffrey N; Christopher B Buck, Cynthia D Thompson, Rhonda Kines, Marcelino Bernardo, Peter L Choyke, Douglas R Lowy, John T Schiller (July 2007). "Genital transmission of HPV in a mouse model is potentiated by nonoxynol-9 and inhibited by carrageenan". Nat Med 13 (7): 857–861. doi:10.1038/nm1598. ISSN 1078-8956. PMID 17603495. "A widely used vaginal spermicide, nonoxynol-9 (N-9), greatly increased susceptibility to infection. ... As expected, the CMC-based gel containing N-9 rendered the mucosa susceptible to significant HPV pseudovirus infection (P = 0.03), while the carrageenan-based gel prevented detectable infection. ... Overall, these results raised the possibility that use of over-the-counter N-9-containing vaginal contraceptives is a risk factor for genital HPV infection in women."
- Safety of Nonoxynol-9 when used for contraception World Health Organization (October 2001)
- Vaginal Spermicide: Nonoxynol Family Practice Notebook.com
- Docs: 'Nonoxynol-9 Doesn't Work' Wired News: Lite, Jordan (May 13, 2002)
- Info on microbicides
- ChemSub Online: Nonoxynol-9
- Record in the Household Products Database of NLM