Nonoxynol-9, sometimes abbreviated as
N-9, is a non-ionic nonoxynol
surfactantSurfactants are wetting agents that lower the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension between two liquids.- Etymology :The term surfactant is a blend of surface active agent...
that is used as an ingredient in various cleaning and cosmetic products, but is also widely used as a contraceptive for its spermicidal properties.
Although it was at one time widely promoted as a protection against sexually transmitted infections including
HIVHuman immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections. Infection with HIV occurs by the transfer of blood, semen, vaginal fluid,...
, subsequent studies have shown that it can in fact
increase the risk of infection by damaging the physical barriers of the rectum or vagina.
As a
spermicideSpermicide is a substance that kills sperm, inserted vaginally prior to intercourse to prevent pregnancy. As a contraceptive, spermicide may be used alone. However, the pregnancy rate experienced by couples using only spermicide is higher than that of couples using other methods...
, it attacks the
acrosomalThe acrosome is an organelle that develops over the anterior half of the head in the spermatozoa of many animals. It is a cap-like structure derived from the Golgi apparatus. Acrosome formation is completed during testicular maturation. In Eutherian mammals the acrosome contains digestive enzymes...
membranes of the
spermA sperm, from the ancient Greek word σπέρμα and and more commonly known as a sperm cell, is the haploid cell that is the male gamete. It joins an ovum to form a zygote. A zygote is a single cell, with a complete set of chromosomes, that normally develops into an embryo.Sperm cells contribute...
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-useEfficacy is the capacity to produce an effect. It is used to mean different specific things in different fields.- Healthcare :In a healthcare context, efficacy indicates the capacity for beneficial change of a given intervention Efficacy is the capacity to produce an effect. It is used to mean...
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
lubricatedPersonal lubricants are specialized lubricants which serve, during sexual acts , to reduce friction with the penis, vagina, anus or other body parts...
with solutions containing nonoxynol-9.
Nonoxynol-9, sometimes abbreviated as
N-9, is a non-ionic nonoxynol
surfactantSurfactants are wetting agents that lower the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension between two liquids.- Etymology :The term surfactant is a blend of surface active agent...
that is used as an ingredient in various cleaning and cosmetic products, but is also widely used as a contraceptive for its spermicidal properties.
Although it was at one time widely promoted as a protection against sexually transmitted infections including
HIVHuman immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections. Infection with HIV occurs by the transfer of blood, semen, vaginal fluid,...
, subsequent studies have shown that it can in fact
increase the risk of infection by damaging the physical barriers of the rectum or vagina.
Spermicide
As a
spermicideSpermicide is a substance that kills sperm, inserted vaginally prior to intercourse to prevent pregnancy. As a contraceptive, spermicide may be used alone. However, the pregnancy rate experienced by couples using only spermicide is higher than that of couples using other methods...
, it attacks the
acrosomalThe acrosome is an organelle that develops over the anterior half of the head in the spermatozoa of many animals. It is a cap-like structure derived from the Golgi apparatus. Acrosome formation is completed during testicular maturation. In Eutherian mammals the acrosome contains digestive enzymes...
membranes of the
spermA sperm, from the ancient Greek word σπέρμα and and more commonly known as a sperm cell, is the haploid cell that is the male gamete. It joins an ovum to form a zygote. A zygote is a single cell, with a complete set of chromosomes, that normally develops into an embryo.Sperm cells contribute...
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-useEfficacy is the capacity to produce an effect. It is used to mean different specific things in different fields.- Healthcare :In a healthcare context, efficacy indicates the capacity for beneficial change of a given intervention Efficacy is the capacity to produce an effect. It is used to mean...
failure rates for five nonoxynol-9 vaginal contraceptives (film, suppository, and gels at three different concentrations) ranged from 10% to 20%.
Condoms
Many models of condoms are
lubricatedPersonal lubricants are specialized lubricants which serve, during sexual acts , to reduce friction with the penis, vagina, anus or other body parts...
with solutions containing nonoxynol-9. In this role, it has been promoted as a backup method for pregnancy and STD prevention in the event of condom failure.
However, the 2001
WHOThe World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health...
/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.
Additionally, the WHO statement suggests that N-9 should not be used rectally under any circumstances.
Compared to regular lubricated condoms, condoms containing nonoxynol-9 present another disadvantage-- they have a shorter expiration date.
Cervical barriers
Almost all brands of
diaphragmThe diaphragm is a cervical barrier type of birth control. It is a soft latex or silicone dome with a spring molded into the rim. The spring creates a seal against the walls of the vagina.-Use:...
jelly contain nonoxynol-9 as the active ingredient. This jelly may also be used for a
cervical capThe cervical cap is form of barrier contraception. A cervical cap fits over the cervix and blocks sperm from entering the uterus through the external orifice of the uterus, called the os...
.
Most
contraceptive spongeThe contraceptive sponge combines barrier and spermicidal methods to prevent conception. Three brands are marketed: Pharmatex, Protectaid and Today. Pharmatex is marketed in France and Quebec; Protectaid in Canada and Europe; and Today in the United States. For a while, the Today brand was not...
s contain nonoxynol-9 as an active ingredient.
Shaving cream
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.
Sports cream
Nonoxynol-9 is also found in Bengay Vanishing Scent as an inactive ingredient.
Side effects
Nonoxynol-9's ability to kill microbes
in vitroA procedure performed in vitro is performed not in a living organism but in a controlled environment, such as in a test tube or Petri dish...
was initially taken as evidence that it might be effective at preventing STD transmission. However, more recent findings indicate that it may actually increase a person's risk of contracting STDs, especially if used frequently. This is because the chemical causes tiny abrasions inside the sensitive
vaginaThe vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...
l and
analThe anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to expel feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest, such as bones; food...
walls. These abrasions may make transmission more likely especially if condoms are not used.
From 1996 to 2000, a
UNThe United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and the achieving of world peace...
-sponsored study carried out in several locations in
AfricaAfrica is the world's second-largest and second most-populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area. With a billion people in 61 territories, it accounts for about 14.8% of the...
followed nearly 1000 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.
While 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."
Nonoxynol-9 based products (including condoms containing the spermicide) should not be used for prevention of HIV or STDs or for contraception between non-monogamous partners because of the increased risk of infection by HIV or sexually transmitted infections. However, non-spermicide condoms are available and are still highly successful at preventing both pregnancy and STD transmission.
Regular use of nonoxynol-9 likely increases the risk of infection with sexually transmitted
human papillomavirusA human papillomavirus is a papillomavirus that infects the epidermis and mucous membranes of humans. HPV can lead to cancers of the cervix, vulva, vagina, and anus in women. In men, it can lead to cancers of the anus and penis....
es (HPVs) that can cause
cervical cancerCervical cancer is malignant neoplasm of the cervix uteri or cervical area. It may present with vaginal bleeding but symptoms may be absent until the cancer is in its advanced stages...
. 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
carrageenanCarrageenans or carrageenins are a family of linear sulphated polysaccharides extracted from red seaweeds.The origin of the name is unclear and references to a county in Ireland are common but false. It is most likely to derive from an Irish language phrase for "little rock"...
-based lubricants mixed 1:1 with N-9. Two consumer products containing carrageenan, Divine No. 9 and BIOglide, prevented detectable HPV infection in the study.
Frequent use of nonoxynol-9 is linked to higher risk of
urinary tract infectionA urinary tract infection is a bacterial infection that affects any part of the urinary tract.The main causitive agent is:Escherichia coli. Although urine contains a variety of fluids, salts, and waste products, it usually does not have bacteria in it. When bacteria get into the bladder or kidney...
s (UTIs).
Some people have reported allergic reactions to Nonoxynol-9; however, it is possible to test it oneself on the lymph nodes on the upper thigh by the groin to see if one is hypersensitive. If so, the skin usually turns red and causes a burning sensation. Recovery from an allergic reaction usually takes about 6-8 hours.
Alternatives
Chemically speaking, there are two alternatives to nonoxynol-9 spermicide:
- Menfegol: Available as a foaming tablet in Europe.
- Benzalkonium chloride
Benzalkonium chloride, also known as alkyldimethylbenzylammonium chloride and ADBAC, is a mixture of alkylbenzyldimethylammonium chlorides of various even-numbered alkyl chain lengths. This product is a nitrogenous cationic surface-acting agent belonging to the quaternary ammonium group...
: The active ingredient in one brand of contraceptive spongeThe contraceptive sponge combines barrier and spermicidal methods to prevent conception. Three brands are marketed: Pharmatex, Protectaid and Today. Pharmatex is marketed in France and Quebec; Protectaid in Canada and Europe; and Today in the United States. For a while, the Today brand was not...
, available only in France.
For use with a cervical barrier such as a
diaphragmThe diaphragm is a cervical barrier type of birth control. It is a soft latex or silicone dome with a spring molded into the rim. The spring creates a seal against the walls of the vagina.-Use:...
, a jelly containing
lactic acidLactic acid , also known as milk acid, is a chemical compound that plays a role in several biochemical processes. It was first isolated in 1780 by a Swedish chemist, Carl Wilhelm Scheele, and is a carboxylic acid with a chemical formula of C
3H
6O
3...
may work as a substitute.
Lactic acid is known to immobilize sperm, also. But in contrast with nonoxynol-9, this immobilization seems to be reversible and is for that reason less reliable.
External links