On Thursday, a drug for female sex drive called flibanserin will once again be considered by the FDA for approval. It’s already been rejected twice by the agency, which has cited a lack of proof for its effectiveness as well as side effects like sleepiness and nausea. This time around it could get the stamp of approval, or it could fall in with several other failed attempts at a drug for women’s sexual desire.

Sprout Pharmaceuticals, which owns flibanserin, is not the first to put time and resources into a drug to enhance women’s desire for sex. Pfizer, for instance, had been trying to invent a successful Viagra for women more than 15 years ago, and in 2004, they gave up, saying sexual desire for men and women are very different, and that for women, arousal and desire are not necessarily always related. That same year, the FDA rejected a testosterone patch for women citing concern over its long-term safety. In the intervening decade, many other attempts have been made to develop a little pill as effective—and popular—with women as Viagra is with men.

Why some women have low sexual desire is still the subject of some debate. A lack of desire can, some experts say, signal non-biological issues like stress or trouble in the relationship. But many experts believe that’s not the full picture and there’s a biological basis for libido.

“I think it would be nice if a drug like this could work, having better sex is important to my patients,” says Dr. Mary Jane Minkin, a clinical professor of obstetrics, gynecology and reproductive services at Yale School of Medicine. “The earlier results showed it definitely increased desire, but the benefit was not overwhelming enough.”

MORE: ‘Women’s Viagra’ to Seek FDA Approval, Again

Sprout’s flibanserin is intended to treat pre-menopausal women with Hypoactive Sexual Desire Disorder (HSDD) and works by targeting neurotransmitters in the brain involved with sexual arousal and desire. The drug is thought to temporarily lower levels of serotonin and increase levels of dopamine and norepinephrine in the brain. The company says its clinical trials have shown that when placebo is accounted for, women experience a 37% increase in sexual desire.

Those who don’t support the drug’s approval say it doesn’t have enough evidence to back it up. The drug is intended to be used daily, which some in the medical community say raises concerns over its long-term safety. And some experts argue that flibanserin may not be the blockbuster drug it’s being made out to be. “This one is not a fabulous drug, but it would be nice to have it. It’s for someone else to decide if nausea is worth more libido,” says Minkin.

Whether the tide changes for flibanserin this week is yet to be seen, but it underlines the ongoing debate over just how complicated sexuality can be.

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