PT-141 (Bremelanotide)
Bremelanotide · Vyleesi
An FDA-approved melanocortin agonist that acts on the brain to increase sexual desire.
Class
Melanocortin receptor (MC4R) agonist
Half-life
~2.7 hours
Evidence
Randomized human trials
Randomized human trials
Supported by randomized controlled trials in humans. Several compounds at this level are FDA-approved for specific indications.
Overview
PT-141, or bremelanotide, is one of the few compounds in this library that is genuinely FDA-approved — for hypoactive sexual desire disorder (HSDD) in premenopausal women, marketed as Vyleesi. It is unusual among treatments for sexual dysfunction because it works centrally, in the brain, rather than on blood flow like PDE5 inhibitors (Viagra, Cialis).
It is a melanocortin receptor agonist, activating MC4R in the hypothalamus to increase sexual desire and arousal. Because the mechanism is central, it can help with the desire component that vascular drugs do not address, and it is used off-label in men as well, sometimes in combination with PDE5 inhibitors.
Its main practical drawbacks are nausea (common) and transient increases in blood pressure with a compensatory drop in heart rate — which is why it carries cardiovascular cautions. It is taken on-demand before anticipated activity, not daily.
How it works
- Agonises melanocortin receptors, primarily MC4R, in the hypothalamus.
- Increases sexual desire and arousal through central nervous system pathways.
- Acts independently of the vascular (nitric oxide/PDE5) pathway.
- Transient pressor effect — raises blood pressure and lowers heart rate for several hours.
What the research shows
Researched effects
- Improved sexual desire and reduced distress in premenopausal women with HSDD (RECONNECT trials)
- Off-label improvement in erectile function, especially combined with PDE5 inhibitors
- Effect on desire, not just physical arousal
- On-demand rather than continuous dosing
Limitations & what it won't do
- Nausea is common and can be significant.
- Transient blood pressure increase limits use in cardiovascular disease.
- Approved indication is narrow (premenopausal HSDD); other uses are off-label.
- Can cause skin darkening with frequent use (melanocortin pathway).
Dosing protocols
These ranges reflect published trials and community protocols. They are reference information, not a prescription. Doses are per injection unless noted.
On-demand (Vyleesi labelling)
1.75 mgThe approved dose is 1.75 mg. Many off-label users start lower (1 mg) to gauge nausea. Do not exceed one dose in 24 hours.
Reconstitution & measuring your dose
Handling
- Typical vial sizes
- 5 · 10 mg
- Suggested BAC water
- 2 mL
- Storage
- Lyophilised powder refrigerated at 2–8 °C, protected from light.
- After reconstitution
- Reconstituted: approximately 30 days refrigerated.
Why 2 mL? A 10 mg vial in 2 mL yields 5 mg/mL — a 1.75 mg dose lands on 35 units, a 1 mg starter dose on 20 units of a U-100 syringe. The branded autoinjector is pre-dosed.
Dose calculator
Draw to
35units
= 0.35 mL · 50 mcg per unit
Concentration
5000 mcg/mL
Doses per vial
5
Side effects
Common
- Nausea (very common, sometimes requiring an anti-emetic)
- Flushing
- Headache
- Injection-site reactions
- Transient blood pressure increase
Serious / rare
- Significant transient hypertension
- Skin hyperpigmentation (face, gums, breasts) with repeated use
- Priapism (prolonged erection) rarely in men
Contraindications & interactions
Do not use if you have
- Cardiovascular disease
The transient pressor effect makes uncontrolled cardiovascular disease a contraindication — the label warns against use in known CVD.
- Pregnant, breastfeeding, or trying to conceive
Contraindicated in pregnancy.
Use caution if you have
- High blood pressure
PT-141 transiently raises blood pressure; uncontrolled hypertension is a contraindication and controlled hypertension requires caution.
- Melanoma, atypical moles, or high skin-cancer risk
Melanocortin agonism can stimulate melanocytes; caution with melanoma or heavy mole burden.
- Arrhythmia or palpitations
The heart-rate change with dosing warrants caution with rhythm disorders.
Medication interactions
- cautionPDE5 inhibitors — Both affect blood pressure; combining can cause additive hypotension despite PT-141's pressor effect. Space dosing and monitor.
- avoidNitrates — Combining vasoactive sexual-function agents with nitrates risks dangerous blood-pressure swings.
- monitorBlood pressure medication — The transient pressor effect can transiently oppose blood-pressure medication.
Don't stack with
- Melanotan II — Both are melanocortin agonists — combined they compound nausea, pigmentation, and cardiovascular effects.
What to monitor
- Blood pressure response, especially with the first dose
- Skin pigmentation with repeated use
- Nausea tolerability
Commonly combined with
References
- Kingsberg SA et al. — Bremelanotide for HSDD: Two Randomized Phase 3 Trials (RECONNECT)Obstet Gynecol 2019;134:899-908
Research & educational information only — not medical advice.
You must be 18 or older to use this site. The peptides described are presented as research chemicals intended for research purposes only. Most are not approved by the FDA for human use. Dosing ranges reflect what has appeared in the scientific literature or community protocols and are not prescriptions. Nothing here replaces evaluation by a licensed physician who knows your full medical history.
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