---
title: "How Does PT-141 (Bremelanotide) Work?"
url: https://www.primaralabs.com/answers/how-does-pt-141-work
source: Primara Labs, markdown mirror of the HTML page
---

# How does PT-141 work?

PT-141 is bremelanotide, a synthetic peptide that activates melanocortin receptors, chiefly MC3R and MC4R, in the brain rather than acting on blood vessels. As of 23 September 2026, its main evidence is RECONNECT, two 24-week phase 3 trials in premenopausal women with hypoactive sexual desire disorder, where nausea was the most common adverse event.

Primara Labs sells some of the compounds covered here. Every figure on this page links to its source and the date it was checked.

Updated 23 September 2026

01

## The receptors

Bremelanotide is a synthetic peptide analogue of alpha-melanocyte-stimulating hormone that acts as an agonist at melanocortin receptors, chiefly MC3R and MC4R. Investigators link MC4R agonism to its effects on sexual desire; MC4R also regulates appetite, which is why it was studied for food intake.

02

## What RECONNECT measured

In RECONNECT (studies 301 and 302), a phase 3 trial of bremelanotide in premenopausal women with hypoactive sexual desire disorder (n=1,267), the FSFI desire domain score difference from placebo was +0.30 points on study 301, 1.75 mg and +0.42 points on study 302, 1.75 mg over 24 weeks (Kingsberg SA et al. Obstet Gynecol 2019 (RECONNECT)).

In the same two phase 3 trials, distress related to low sexual desire (FSDS-DAO item 13) fell 0.37 and 0.29 points more than placebo.

03

## Adverse events

The most frequently reported adverse events were nausea in 40.0% on 1.75 mg, integrated phase 3 against 1.3% on placebo, flushing in 20.3% on 1.75 mg, integrated phase 3 against 1.3% on placebo, headache in 11.3% on 1.75 mg, integrated phase 3 against 1.9% on placebo and injection site reactions in 5.4% on 1.75 mg, integrated phase 3 against 0.5% on placebo (Safety profile across the clinical programme, J Womens Health 2022 (integrated double-blind phase 3, N=1,247)). The safety review reports nausea as the most common reason for stopping bremelanotide, without a rate.

Across the development programme, focal skin darkening was rare at labelled use but occurred in more than a third of people given up to 16 consecutive daily doses, and small, transient blood pressure rises were seen on ambulatory monitoring.

Sources

## Where every figure comes from

1.  [Bremelanotide mechanism source](https://doi.org/10.1111/j.1743-6109.2006.00268.x) · checked 23 September 2026
2.  [Kingsberg SA et al. Obstet Gynecol 2019 (RECONNECT)](https://doi.org/10.1097/AOG.0000000000003500) · checked 23 September 2026
3.  [J Womens Health 2022](https://doi.org/10.1089/jwh.2021.0191) · checked 23 September 2026

Last reviewed 23 September 2026

Read next

## Related pages

-   [PT-141 10mg](https://www.primaralabs.com/marketplace/pt-141-10mg)
-   [RECONNECT on the Trial Explorer](https://www.primaralabs.com/research/trials/reconnect)

-   [Is PT-141 FDA approved?](https://www.primaralabs.com/answers/is-pt-141-fda-approved)
-   [Which peptides have phase 3 trials?](https://www.primaralabs.com/answers/which-peptides-have-phase-3-trials)