In the past, public health experts recommended using condoms combined with Nonoxynol-9 (N-9), a spermicide, for increased protection against pregnancy, HIV, and STDs. Two recent studies, however, call into question the effectiveness and safety of N-9.
A study published by UNAIDS found that N-9 used without condoms was ineffective against HIV transmission. This study actually showed some evidence that N-9 increased the risk of HIV infection.
Researchers note that this study was conducted among commercial sex workers in Africa who are at increased risk and used a N-9 gel on a frequent basis. The adverse effects might not be seen at the same level among women who are using N-9 less frequently or in a different formulation.
As a result of this study, however, the CDC concluded that given that N-9 has been proven ineffective against HIV transmission, the possibility of risk, with no benefit, indicates that N-9 should not be recommended as an effective means of HIV-prevention.
A similar study published in the Journal of the American Medical Association found that N-9, when used with condoms, did not protect women from the bacteria that causes Gonorrhea and Chlamydia infection any better than condoms used alone.