Is PT-141 Nasal Spray or Injection Better?

Neither form has been shown to work better at raising desire, because no study has compared PT-141 nasal spray and injection head to head. The injection has the strongest evidence. PT-141 (bremelanotide) was tested as an injection in two large trials of 1,267 premenopausal women and approved by the FDA as Vyleesi. The nasal spray skips the needle, but its published data in women is one study of 18 women. Bremelanotide started out as a nasal spray, and its developers moved to the injection because nasal absorption varied widely from woman to woman. Your choice is between a predictable, well-studied dose and a needle-free spray with far less evidence behind it.

What is the difference between PT-141 nasal spray and injection?

The injection is an FDA-approved, fixed dose backed by large trials. The spray is made to order by a pharmacy, is not FDA-approved and has much less data on how much drug reaches your body.

HSDD means low desire that bothers you and is not explained by another cause. "Compounded" means a licensed pharmacy prepares the spray to order for one patient. Rebody describes its spray as a different product from Vyleesi that does not carry Vyleesi's approval or indication, and it notes that compounded medications are not FDA-evaluated for safety, effectiveness or quality.

Why did PT-141 switch from a nasal spray to an injection?

The spray delivered unpredictable amounts of the drug. When bremelanotide was first developed as a nasal spray, absorption varied so widely that some women could get more drug than they needed. That raised their risk of side effects such as higher blood pressure. Other women got too little. The developers built the injection so the dose you take would match the amount in your body more closely.

The spray does have some human data in women. In a small study, 18 premenopausal women with arousal problems each got one 20 mg nasal dose and one placebo dose in a clinic. More of them reported moderate or high desire after the drug than after placebo. Among the women who tried intercourse within 24 hours, more were satisfied with their arousal after the drug. Blood flow to the vagina while they watched an erotic video did not change significantly.

That study used a research formulation at a research dose. A compounded spray you buy today is a different product at a different strength. Rebody says so on its own page: the study used "a research formulation at a research dose, not the Rebody bottle."

Our take: if needles are what's stopping you, the spray is a real option. You trade a predictable dose for convenience, so tell your clinical team how each dose makes you feel.

How well does the PT-141 injection work for low desire?

For many women, it works. In two 24-week trials, 58% of women on the injection counted as responders, meaning they reported a meaningful benefit. On placebo, 35% did.

Women felt more desire and were less bothered by low desire by week 4, the first check-in, and the change held through 24 weeks. The average gain over placebo was modest. Some women may respond a lot, and others may barely notice a difference.

The number of satisfying sexual encounters did not differ significantly between the drug and placebo. PT-141 works on wanting sex. It is not approved to boost sexual performance.

Women who stayed on it for a year kept improving. In the open-label extension, where everyone knew they were taking the drug, desire and distress scores kept getting better over 52 weeks.

All of these results come from the injection. No nasal spray has been tested in a trial this size, so a spray may not give the same results.

What side effects does PT-141 cause, and how often can I use it?

Nausea is the most common side effect. In the injection trials, 40% of women had nausea, compared with 1% on placebo. It started about 30 minutes after the dose, lasted about 2.4 hours on average and mostly went away without treatment. Flushing (20%) and headache (11%) came next, and 5% of women vomited.

According to the Vyleesi patient information, nausea most often happens after the first dose, so it helps to take your first one on a quiet night. If nausea is severe or does not go away, your clinical team can prescribe an anti-nausea medicine.

Your blood pressure rises a little and your heart rate drops a little after each dose. Both usually return to normal within 12 hours. The label says to take no more than one dose in 24 hours and no more than 8 doses a month.

Darkening of the skin on the face, gums or breasts is rare at labeled doses. In the studies, it showed up in more than a third of people dosed every day for up to 16 days, and it may not fade after you stop.

That is why frequency matters with the spray too. RWell's dosing section says its PT-141 "may be used daily if desired." The spray contains the same molecule, so ask your clinical team before using any form more often than the label's 8 doses a month.

Tell your clinical team if you take naltrexone. Bremelanotide lowered blood levels of naltrexone and of the painkiller indomethacin.

Who is PT-141 right for?

The approved use is narrower than most women expect. PT-141 is approved for premenopausal women whose desire used to be fine, has dropped in every situation and with every partner, and bothers them. The label says it is not for low desire caused by another medical or mental health condition, relationship problems or a medication. It is also not approved for women after menopause or for improving sexual performance.

The label also says not to use it if you have uncontrolled high blood pressure or known heart disease. If you can get pregnant, use effective birth control while you take it, and stop if you think you might be pregnant.

Sometimes desire disappears for reasons a medication won't fix. One woman, finally in a healthy relationship after an abusive one, wrote: "So WHY WHY WHYYYYY am I not horny for this wonderful man WHYYYYY". Tell your clinical team what is going on in your life as well as in your body.

You can still have a drink on date night. Bremelanotide does not interact badly with alcohol, unlike flibanserin, another low-desire medication.

Our clinical team can prescribe PT-141 if it fits your goal, your blood pressure and where you are with menopause. You want to feel like initiating again. Take the quiz so our clinical team can see whether PT-141 fits you.