Overview
PT-141, also known as Bremelanotide, is one of only a few peptides to achieve full FDA approval. Marketed under the brand name Vyleesi, it was approved in June 2019 for the treatment of hypoactive sexual desire disorder (HSDD) in premenopausal women. Unlike drugs like Viagra that act on blood flow, PT-141 works through the central nervous system, acting on melanocortin receptors in the brain.
Mechanism of Action
PT-141 is a synthetic analog of alpha-melanocyte stimulating hormone (α-MSH) that binds to melanocortin receptors, particularly MC4R:
- MC4R activation in the hypothalamus and limbic system
- Central nervous system action — works on sexual desire pathways in the brain, not peripheral blood flow
- Dopamine modulation — increases dopamine activity in reward centers
- Distinct from PDE5 inhibitors — Viagra/Cialis work on blood vessels; PT-141 works on the brain's arousal circuits
This central mechanism means PT-141 addresses desire (libido) rather than just the mechanical aspects of sexual function.
FDA Approval and Clinical Data
Approval History
- Developed from the tanning peptide Melanotan II
- Failed initial trials as a nasal spray (blood pressure concerns)
- Reformulated as subcutaneous injection
- FDA approved June 2019 as Vyleesi (bremelanotide)
Clinical Trial Results
The RECONNECT trials (Phase III) demonstrated:
- Significantly improved sexual desire scores compared to placebo
- Increased satisfying sexual events per month
- Improved distress scores related to low sexual desire
- Effects typically begin within 45-60 minutes of injection
- Duration of effect: approximately 24 hours
Important Limitations
- Approved only for premenopausal women with HSDD
- Not approved for men (though off-label research exists)
- Not approved for sexual arousal disorder or other sexual dysfunctions
- Should not be used more than once in 24 hours or more than 8 times per month
Dosage Information
FDA-Approved (Vyleesi)
- Dose: 1.75 mg subcutaneous injection
- Timing: At least 45 minutes before anticipated sexual activity
- Frequency: No more than once per 24 hours; max 8 doses per month
- Route: Subcutaneous injection in the abdomen or thigh
Safety Profile
Common Side Effects (from clinical trials)
- Nausea — the most common (40% of patients, usually diminishes)
- Flushing (skin warmth and redness)
- Injection site reactions
- Headache
- Hyperpigmentation — darkening of skin, particularly on the face and gums with repeated use
Serious Warnings
- Blood pressure elevation — temporary increase following injection; not recommended for uncontrolled hypertension
- Cardiovascular risk — contraindicated in patients with uncontrolled hypertension or cardiovascular disease
- Skin darkening — may be irreversible with chronic use
- Naltrexone interaction — do not use with naltrexone or opioid medications
Contraindications
- Uncontrolled hypertension
- Cardiovascular disease
- Use of naltrexone
- Post-menopausal women (not studied in this population)
PT-141 vs Other Sexual Health Treatments
| Feature | PT-141 (Vyleesi) | Flibanserin (Addyi) | Viagra/Cialis | | --- | --- | --- | --- | | Target | Brain (MC4R) | Brain (5-HT) | Blood vessels (PDE5) | | Treats | Desire (libido) | Desire (libido) | Erectile function | | For whom | Premenopausal women | Premenopausal women | Men | | Route | Injection | Daily oral pill | Oral (as needed) | | Onset | 45 minutes | Weeks of daily use | 30-60 minutes | | Alcohol | No restriction | Contraindicated | Caution |
Research Beyond HSDD
Off-label and research applications being explored:
- Male sexual dysfunction — some evidence of improved erectile function through central mechanisms
- Hemorrhagic shock — early research on melanocortin receptor agonists for emergency medicine
- Tanning/pigmentation — related to its Melanotan II origins, though this is not an approved use
Research Status
- FDA Status: ✅ FDA-Approved (Vyleesi/Bremelanotide) for HSDD in premenopausal women
- Manufacturer: Palatin Technologies (marketed by AMAG Pharmaceuticals)
- Legal Status: Prescription medication in the US
Profile last updated: January 2026