40% of people using Vyleesi experienced nausea.

Common side effects include nausea (40% of people using bremelanotide), vomiting, temporary skin reddening, reactions at the injection site, and headache. Specifically due to reactions like these, 18% of subjects taking bremelanotide dropped out of the study compared to 2% of subjects taking a placebo injection. Patients shouldn’t take more than one dose in a 24 hour period, and they shouldn’t take it more than 8 times in a month. This recommendation is designed to reduce the risk of high blood pressure. According to the FDA label, people who have uncontrolled hypertension or cardiovascular disease should not take this medication at all.

A small number (1%) of the phase 3 trial subjects reported skin and gum darkening, which did not fade after stopping treatment in about half of cases. Women with darker skin experienced this symptom more often than those with lighter skin, however, both trials were conducted on a rather homogenous group (over 86% were white). Not only does that limit how generalizable the outcome results are, but it also limits our understanding of what side effects truly are “common.”

The effects of taking Vyleesi alongside medications for depression and/or anxiety are not known.

Subjects using hormonal contraceptives at the same time as bremelanotide did not show a statistically significant rise in sexual desire. Interestingly, subjects’ bodies absorbed progesterone or estrogen contraceptives sufficiently despite using bremelanotide at the same time.

According to small controlled trial taking bremelanotide at the same time as drinking alcohol doesn’t cause any ill effects (tested using the equivalent of 3 glasses of wine). This is a notable improvement over a previously approved sex-drive medication.

There’s no information about how bremelanotide affects breast milk or people who are pregnant, but no level of the drug has been deemed safe for pregnant people. Currently, there are only animal studies that suggest extremely high exposures to the drug can lead to fetal harm and developmental effects.

1. Are the increases in desire meaningful to someone who is distressed by lack of desire?
2. If only 20% of subjects completed an exit interview, are those responses a valid expression of the study population?
3. About half as many women randomized to bremelanotide (124) as women randomized to placebo (239) elected to take the drug after the trial ended. Why?
4. Should we be concerned that the people conducting most of the studies on bremelanotide are largely funded by and partnered with the sponsor company?

We know that trial participants were studied in 80 sites in the United States and Canada. Study participants were between 18 and 56 years old, female (presumably cis-gender), and were previously diagnosed with hypoactive sexual desire disorder that persisting for 6 months or more. They were premenopausal with no psychological, gynecological, urological health concerns. 86% were White, 12% of the participants were Black, and only 1% identified as any other race or ethnicity. These exclusions mean that we do not know what the effect of this drug would be on women taking blood pressure medications or medications for depression or anxiety, all of which are known to reduce sexual desire in some people. Nor do we know what the experience of Latina, Indigenous or Asian women would be.

The effects of taking Vyleesi alongside medications for depression and/or anxiety are not known.