Does Addyi (Flibanserin) Actually Work for Low Sex Drive in Women?

A lot of people quietly wonder whether they want sex as much as they "should," and a smaller group is told they have a disorder for it. The question worth asking is whether that disorder is a real medical problem or a relationship problem wearing a lab coat.

What the diagnosis actually requires

Hypoactive sexual desire disorder, called female sexual interest/arousal disorder in the DSM-5, is a clinical diagnosis. It is not the ordinary fact that nobody is in the mood all the time. To qualify, a woman needs to have decreased or absent function in three of six areas: interest in sexual activity, sexual or erotic thoughts and fantasies, initiation or receptiveness to a partner, excitement or pleasure during almost all encounters, arousal to erotic cues, and genital or non-genital sensations during sex.

It has to persist for at least five months. It has to cause significant distress. And it has to not be better explained by something else, like medications, another condition, or relationship stress.

That last clause is where things get slippery. The DSM-5 also drew criticism for lumping desire and arousal into one disorder, because they are not the same thing. Arousal is physiologic. Desire is not. There are women who very much want sex but do not become physically aroused, and the two problems do not respond to the same fix. A separate critique is harder to wave away: that this diagnosis was shaped, in part, to give a drug something to treat.

How much sex is "normal," and the discrepancy problem

There is no normal. There is an average. In a large survey of 26,000 parents, frequency varied a lot with the age of the youngest child. For parents of kids under a year, the most common frequency was once or twice a month. For parents of kids over five, it was closer to one or two times a week. A notable share of people, especially those who reported having sex only a few times a year, said they wanted more. The desire was there. The opportunity was not.

That points to the real driver in most relationships, which is desire discrepancy. A survey of parents' sex lives after kids captured the texture of it: tired couples who, when they do have sex, remember they like it. A study of 1,054 married couples in Archives of Sexual Behavior found that 52% of women and 37% of men said their desired frequency matched what they were actually having. Forty-eight percent of husbands wanted more than the reality, versus 18% of wives. Greater discrepancy was linked to lower relationship satisfaction, more conflict, and worse communication, with modest effect sizes, even after controlling for how often couples had sex. The direction of cause and effect is not clear. A longitudinal version following 229 couples suggested the discrepancy tends to come before the distress.

What helps before you reach for a pill

A study of 229 couples cataloged 17 coping strategies for desire discrepancy. Communication was the standout. Not a single couple called it unhelpful, and 57.1% called it very helpful. Coming in close behind was a strategy bluntly named "have sex anyway," which only 5.3% of couples found unhelpful. This is a real piece of marital counseling advice. You schedule it, you start it even when it feels like eating your vegetables, and for many people the connection follows.

Doing something else together with a partner helped too, as did solo activity, which 80% of couples found useful. The clear loser was disengagement. Doing nothing was consistently tied to the lowest sexual and relationship satisfaction. One caveat matters here: these strategies raised satisfaction, but they did not change desire itself.

The drugs, and what the trials really show

Two drugs are FDA approved. Flibanserin, sold as Addyi, is a pill taken daily at bedtime. It is a serotonin partial agonist, which is a strange mechanism given that SSRIs are known to lower sexual interest. The trials used an outcome called satisfying sexual events. In the pooled data, women on flibanserin gained about 2.1 satisfying events over 28 days versus 1.2 on placebo. Stack the meta-analytic numbers up and the real-world effect looks like roughly half an extra satisfying sexual event per month. The drug is not benign. It can cause hypotension and fainting, and about 40% of women in the trials reported nausea.

The second drug, bremelanotide, sold as Vyleesi, is a peptide given by subcutaneous injection about 45 minutes before sex. It binds an alpha-melanocortin receptor in the brain that appears to modulate sexual behavior. Across the RECONNECT trials, with 1,267 women randomized, it significantly improved the desire subscore on the Female Sexual Function Index, by about 0.35 points in the integrated analysis, and reduced low-desire distress by a similar amount. These are modest numbers. There was no difference in satisfying sexual events. Nausea hit about 40% of users, and because it is a melanotan relative, it can make you tan.

Testosterone is not FDA approved for this, but it probably works. A trial of roughly 600 women in JCEM gave them placebo or testosterone 300 micrograms a day for 24 weeks. The testosterone group gained about two satisfying episodes per month, versus 0.98 on placebo. Other trials show similar effects, which puts it in the same ballpark as the pink pill.

Bottom line

Hypoactive sexual desire disorder is a clinical diagnosis, but much of what gets filed under it looks like couples struggling through a phase of life with too little time and too little conversation. The FDA-approved drugs deliver real but small effects, often around half an extra satisfying event per month, and they carry real downsides. Communication and "have sex anyway" beat doing nothing by a wide margin and have no side effects. If a drug is on the table, the testosterone evidence is at least as strong as the pink pill, with caveats. None of these treatments fix a relationship, and selling them as if they do leaves people worse off.

Here's our discussion from the episode:

I covered this in depth on Wellness, Actually, listen below.

Wellness, Actually Podcast

"What's the deal with hypoactive sexual desire disorder?" — Listen to the full episode, including the week's health news and listener Q&A.