A: Spermicide, or nonoxynol 9, irritates the cells that line the vagina and the rectum, making them more vulnerable to attack by those same viruses and bacteria that the condoms are protecting you against. This is the reason why the package warns you not to use them more than you need to.

Spermicide is a substance that contains chemicals, such as nonoxynol-9, that is put into the vagina prior to sexual intercourse to immobilize/kill sperm before it enters the uterus. Dozens of condoms, vaginal films, jellies, foams and sponges containing the N-9 spermicide are available online or at local pharmacies without a doctor’s prescription.

What's N-9?

N-9 is actually very effective at killing the microorganisms that cause sexually transmitted diseases such as chlamydia, gonorrhea and HIV. There’s just one small problem – it also irritates the cells that line the vagina and rectum, making them more vulnerable to attack those same viruses and bacteria. Basically, spermicide erodes the cells that are present to help protect against these diseases.

However, the impact of N-9 on the vaginal cell wall appears to be dose-related, according to a study by the World Health Organization. Small infrequent doses of N-9 (once a day or less) appear to cause little or no disruption of the cell wall, whereas more frequent, larger doses consistently cause damage.

Our advice to you is to stop using condoms that contain spermicide immediately, as they really don’t do much for decreasing sperm count. Instead, switch to a condom that does not contain N-9. We recommend trying these sensitive condoms.