What is PT-141?
PT-141 (bremelanotide) is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone (alpha-MSH). It acts on melanocortin receptors in the central nervous system to generate sexual arousal signals independently of vascular mechanisms. Originally developed from the tanning peptide Melanotan II, it was found to reliably induce sexual arousal in clinical testing. It received FDA approval in 2019 as Vyleesi (autoinjector, 1.75 mg) for premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD).
Mechanism of action
PT-141 activates melanocortin receptor subtypes MC3R and MC4R in the hypothalamus and limbic system, engaging neurochemical pathways that generate sexual desire and arousal. Unlike PDE5 inhibitors (sildenafil, tadalafil), its mechanism is central (neurological) rather than peripheral (vascular), meaning it works at the level of brain signaling rather than blood flow to genitalia.
Researched benefits
- Increased sexual desire and arousal in clinical trials for both men and women
- Spontaneous erections in men with erectile dysfunction not responding to PDE5 inhibitors in early studies
- Improvement in female sexual function scores (desire, arousal, orgasm) in HSDD trials
- Central mechanism of action distinguishes effects from purely vascular approaches
- Rapid onset of action (30–60 minutes post-injection) studied in clinical settings
Researched dosage
Most research protocols use 1000–2000 mcg administered 1× per day via subcutaneous injection. PT-141 is used on an as-needed basis, not daily. The FDA-approved Vyleesi dose is 1.75 mg (1750 mcg) subcutaneously 45 minutes before anticipated sexual activity, no more than once per 24 hours and no more than once per 8 days. Research protocols have studied 1–2 mg.
Use the calculator below to convert your target PT-141 dose into exact insulin-syringe units.
Reconstitution & storage
A standard 10 mg vial reconstituted with 2 mL of bacteriostatic water yields 5000 mcg/mL. Lyophilized vials stable at 2–8°C. Reconstituted solution should be refrigerated and used within 30 days.
Side effects & considerations
- Nausea (most common, reported in ~40% of Vyleesi trial participants)
- Flushing and warmth, often starting in the face
- Transient blood pressure increase (clinical monitoring recommended)
- Headache and fatigue reported in a subset of trial participants
PT-141 stacks
- Sexual Health Research — paired with Melanotan II. Complementary melanocortin signaling for tanning and sexual function. PT-141 and Melanotan II share MC3R/MC4R activity. Some researchers study their overlapping effects, though PT-141 is considered the more selective sexual-function compound due to reduced tanning and side-effect profile.
Selected research
- Bremelanotide: an overview of preclinical CNS effects on female sexual function — CNS Drug Reviews, 2007
- A randomized, double-blind, placebo-controlled trial of bremelanotide for female sexual dysfunctions — Journal of Sexual Medicine, 2016
- Bremelanotide for hypoactive sexual desire disorder in premenopausal women (RECONNECT studies) — Obstetrics & Gynecology, 2019