For many women, sexual desire goes up and down over the years, often tied to changes in relationships, stress, and physical changes like pregnancy and menopause. But roughly 10% of women deal with a low sex drive that causes them distress. It’s a condition known as hypoactive sexual desire disorder (HSDD).

There are a few over-the-counter supplements that aim to treat the problem, which have limited, mostly unproven, effects. But in recent years, the FDA has approved two prescription drugs to treat HSDD. These treatments are often referred to as “female Viagra” — a nod to one of the medicines that men can take for sexual problems. But they’re not much like Viagra at all. In fact, they work very differently inside the body.

“In men, Viagra fixes a ‘plumbing problem,’ if you will,” says Judith Volkar, MD, of the UPMC Magee-Womens Hospital in Pittsburgh. Viagra and other similar drugs treat erectile dysfunction, when a man can’t get or keep an erection that’s firm enough to have sex. These men often still have sexual desire, but they just can’t get their bodies to respond physically when they want to have sex. The drugs help by relaxing the muscles in the penis and boosting blood flow so an erection can happen.

The drugs the FDA has approved for HSDD are:

• Flibanserin (Addyi): It’s a pill you take every evening.
• Bremelanotide (Vyleesi): It’s a shot you give yourself in the belly or thigh 45 minutes before you have sex. You take one in a 24-hour period, and doctors recommend only eight shots per month.

How they work. Both drugs boost the activity of chemical messengers in your brain, called neurotransmitters, that are key to helping you feel aroused. You take flibanserin every day, whether you plan to have sex or not. You inject bremelanotide only when you need it. It’s important to note that neither drug makes sex better. They just make you more likely to feel in the mood.

Your doctor may recommend that you try sex education and counseling along with the medication. You may also need hormone therapy, if you deal with any physical issues that affect sex, such as vaginal dryness.

How do I get them? Your doctor needs to diagnose you with HSDD in order to prescribe either drug. They can do that by asking screening questions, such as:

• Have you been satisfied with your level of sexual desire before?
• Has your sex drive gotten lower?
• Does your lack of libido bother you?
• Would you like it to increase?
• Are there other things (medication, pregnancy, surgery, stress) that could be affecting your sex drive?

If you answer “yes” to the first four questions, and there’s no other cause for your low sex drive, you probably have HSDD.

Volkar says the distress that a woman feels about her sex drive is often the driving factor in whether or not she needs to take medicine for it. “Because if you aren’t bothered by it, it’s not a problem,” she says.

Researchers have mainly studied how the medicines work in women who haven’t gone through menopause yet. So the FDA approved both drugs for premenopausal women only. Women who are pregnant or breastfeeding should not use either drug.

There are others who shouldn’t take the medications, including those who:

“They can also interact with several drugs women commonly take, like fluconazole (Diflucan), which is a yeast infection medication, and also some antibiotics,” Volkar says. “So it’s good to be aware of what medications you’re on and discuss those with your doctor.”

Women who use HSDD medications shouldn’t drink alcohol from 2 hours before they take the drug until the following morning, because it can lower blood pressure to dangerous levels.

The drugs can cause side effects, such as:

Bremelanotide can cause your skin and gums to get darker.

To measure how well these drugs treat HSDD, doctors look at whether sexual desire has gone up and if distress about it has gone down. Volkar says flibanserin typically leads to “one more sexually significant event per month.” That may sound like a success to some and not to others.

“It depends on how you define things,” she says. “Is that awesome, or is that not so great? When I’m counseling a patient, I kind of leave that to their discretion and let them decide what that means for them.”

There is no “normal” amount of sex or desire. So a change in the distress a woman feels about her sex drive is often a key sign of how well the treatment is working.

If you try the medicine for 8 weeks and you haven’t felt a change, your doctor may recommend you stop taking it.

The bottom line, Volkar says, is that though these treatments may not be perfect yet, having two medications available on the market is a move in the right direction.

“I think it’s great that we’re finally doing research into medications for women and sexual desire,” she says. “I don’t think it’s quite the answer yet, but it’s an important first step.”