Crimson illustration of a ring of seven beads next to a glowing network of brain cells

BREMELANOTIDE · 7 AMINO ACIDS · RING-SHAPED

PT-141.
A Peptide That Works in the Brain

Most medicines for sexual problems act on blood flow. PT-141 works differently: it acts on signalling pathways in the brain that are linked to desire. Developed under the name bremelanotide, it became a US prescription medicine for women in 2019, sold as Vyleesi. Here you can read what it is, what the studies found and where it stands in Europe.

Start With the Basics See the Studies

Bremelanotide is approved in the US for one specific condition in women, but no product is licensed in the EU or the UK. Research-grade PT-141 is made for laboratory use only. This site does not give medical advice.

Why It Exists

PT-141 began with a surprise. In the early 1990s, researchers testing an experimental tanning peptide noticed that some male volunteers had an unexpected side effect: spontaneous erections. A small US company, Palatin Technologies, set out to keep that effect and leave the tanning behind. The result was PT-141, a short peptide folded into a ring.

Instead of widening blood vessels like the well-known erection pills, it switches on melanocortin receptors in the brain. These receptors help control appetite, skin colour and sexual motivation. That is why it was tested both in men with erectile problems and in women with low desire.

Its road to the pharmacy was long. A nasal spray was dropped in 2008 because it raised blood pressure, and an injection won US approval in 2019 for premenopausal women whose low sexual desire causes distress. The pages below explain each step.

At a Glance

What it is	A synthetic, ring-shaped peptide of seven amino acids, related to the body's own hormone alpha-MSH
Other names	Bremelanotide and bremelanotide acetate; brand name Vyleesi
Molar mass	About 1,025 g/mol
Target	Melanocortin receptors in the brain, above all the MC4 receptor
Approved use	In the US only: premenopausal women with acquired, generalised hypoactive sexual desire disorder (HSDD)
Market history	Developed by Palatin Technologies; FDA approval in June 2019; sold to Cosette Pharmaceuticals in 2023
Status	No marketing authorisation in the EU or the UK

Please Keep in Mind

Nothing here is medical advice, and research-grade PT-141 is not intended for people. If you have concerns about desire, arousal or your sex life, a doctor is the right person to talk to.