A male birth control pill that dramatically lowers testosterone levels is moving forward into a 3-month trial

A new kind of male birth control pill was recently tested in a month-long trial, and is moving forward into a three-month study — the next step in the FDA approval process.
The pill is taken once daily with a meal.
Some men who took it gained a few pounds, and some decreased their levels of "good" HDL cholesterol.
The experimental pill is at least five to 10 years away from coming to market.

For decades, men have had only two ways to actively avoid impregnating a partner: wear a condom (which are about 85% effective) or get a vasectomy.

But doctors Stephanie Page from the University of Washington and Christina Wang from

en actually are very interested in contraception," Page told Business Insider. "Between vasectomy and condoms, they do about 17% of the contracepting in the United States. They just don't have a lot of choices."

works by suppressing male body's natural sex hormone (testosterone). In its current form, the pill lowers a man's testosterone levels to what they were in boyhood or lower, essentially like a chemical castration.

To balance out the effects of men's low testosterone levels while taking the drug, the patients were given a synthetic androgen, or male steroid hormone, to help them maintain their "male" characteristics. The artificial hormone is designed to mimic the role testosterone plays in non-sperm-related functions in the body, like sex drive, musculation, and hair growth.

When men stop taking the pill, their natural hormones should have a resurgence, and they'll be able to impregnate again. It's similar to the way hormonal birth control works in women.

The pill

Now that the researchers have seen that their pill can indeed lower men's testosterone, the longer study will assess how effectively the men's sperm count is annihilated by those lower testosterone levels.

the initial one-month trial did raise concerns about other side effects.

Like a lot of women who take hormonal birth control, some men gained weight on the pill. Some put on a few pounds, some gained none, and one unlucky man gained nearly nine pounds in the one-month study. In general, the men also saw their levels of HDL cholesterol (considered the good kind) drop slightly.