Researchers at Laval University in Quebec City, Canada have reported in the Sexually Transmitted Diseases journal that an experimental heat-activated microbicide gel has shown to effectively act as a physical barrier to HIV and herpes infection, Reuters Health reports.

Also known as the "invisible condom," the gel's microbicide compounds also work to destroy any HIV or herpes viruses that come into contact with the barrier. The microbicide is applied in liquid form to the vagina, where it spreads and coats the vaginal lining when heated to body temperature.

Lead researcher Jocelyne Piret reports that the gel remained effective for as long as six hours in lab tests. Phase I clinical trials of the substance are scheduled for later this year. The researchers hope the product is approved for general use as soon as next year.

According to the SafeGuards Gay Men's Health Project, more than sixty possible product leads have been developed so far and about one third of them are in, or ready for, human testing. The lack of research funds has kept the field moving as quickly as it could. The Global Campaign for Microbicides estimates that US$75 to US$100 million a year would move products through the research pipeline efficiently and get one or more of them on the market within the next five years.

Most of the current research focuses on vaginal use, mainly due to the fact that women's bodies are more vulnerable to infection and its consequences as well as persistent gender inequities. In many areas of the world, women (whether or not they are commercial sex workers) have limited access to condoms or are unable to negotiate their use with male partners. All existing defences require male cooperation (condoms, monogamy) or at least agreement (the female condom).

Research involving MSM (men who have sex with men) carries the moral and social stigma that is still attached to homosexuality. However, in June this year, scientists specializing in rectal microbicide research have gotten together to plan first full-scale rectal microbicide trials. Few other studies looking at penile and rectal irritation are also underway.

Understandably, MSM are eager for such a product to hit the consumer market. Safeguards, however, strongly emphasize that microbicides are being "designed to enhance condom effectiveness for people who choose to use them along with a condom." Having said that, they have also acknowledged that for men who insist on barebacking (having intercourse without a condom), microbicides will provide more protection than using nothing.

Please be advised that none of this information should be your only source when making health and wellness decisions and it should not take the place of consultation with your health care professional.