What it is
PT-141 is a peptide made of 7 amino acids joined in a ring. It is made in a lab. It was made from Melanotan II by changing the very end of the chain. It attaches to melanocortin receptors in the brain, mainly MC3R and MC4R. The FDA approved it in 2019 under the brand name Vyleesi. It is approved only for low sexual desire, called hypoactive sexual desire disorder, in women who have not gone through menopause. It acts on the brain, not on blood vessels. Drugs like sildenafil act on blood vessels. Other names: Bremelanotide, Vyleesi.
What researchers study it for
- Sexual desire in women
- Erection response in men
- Melanocortin receptors in the brain
- How the brain controls sexual behavior
What the studies found
1. Two large trials led to its FDA approval.
Two 2019 trials enrolled more than 1,200 women with low sexual desire. They used PT-141 or a placebo shot as needed for 24 weeks. Desire scores went up more with PT-141 than with placebo. Distress about low desire went down more. The most common side effect was nausea, reported by about 40 percent of women on PT-141.
2. The peptide it came from caused erections in men with erectile problems.
This 1998 study tested Melanotan II, the parent of PT-141. Ten men whose erection problems had no physical cause got Melanotan II and a placebo on different days. Eight of the ten had erections measured by a device. Side effects were nausea, yawning, and stretching. This result is what led researchers to build PT-141.
3. The MC4R receptor controls sexual response in mice.
A 2002 study used a drug that only turns on MC4R. It increased erection response in normal mice but did nothing in mice bred without MC4R. Mice without MC4R also mated less. The receptor was found on nerves in the brain, spinal cord, and penis, but not on the muscle cells of blood vessels. This is why PT-141 is said to work through nerves, not blood flow.
How much research exists
Two large human trials plus earlier smaller human trials. It is one of very few research peptides to reach full FDA approval. Studies in men were done but never taken to approval.
Facts
- Formula: C50H68N14O10
- Weight: 1025.2 g/mol
- CAS number: 189691-06-3
- Sequence: Ac-Nle-cyclo(Asp-His-D-Phe-Arg-Trp-Lys)-OH
- Time in the blood: about 2.7 hours
- Storage: keep the dry powder at room temperature or in the fridge. Keep mixed solution in the fridge.
Legal status
Approved by the FDA in 2019 as Vyleesi, by prescription only, for low sexual desire in women who have not gone through menopause. Research-grade PT-141 is not the approved product and is not approved for human use.
For research use only. Not for human use. Nothing here is medical advice.