Educational reference only. Not medical advice. Consult a healthcare provider before starting any protocol.
PT-141 (Bremelanotide)
Bremelanotide (Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH)
What it is
A cyclic heptapeptide melanocortin receptor agonist, FDA-approved in 2019 as Vyleesi for the treatment of acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women. PT-141 is a synthetic analog of alpha-MSH and an active metabolite of Melanotan II, differing by the absence of the C-terminal amide. Its therapeutic effect is attributed primarily to MC4R activation in the hypothalamic medial preoptic area, increasing dopamine release in neural circuits governing sexual desire. It is the first and only on-demand injectable treatment approved for HSDD.
Community-reported ranges
Dosing and side effects sourced from FDA prescribing information (NDA 210557). Clinical trial data from published phase III results. Not dosing guidance.
Reported dose range
1750–1750 mcg
Estimated half-life
~2.7 hours
Source: FDA prescribing information (NDA 210557)
Reported cycle length
8–8 weeks on
Discontinue after 8 weeks if no improvement (per FDA label) weeks off
Route
subcutaneous
Common vial sizes
1.75mg autoinjector
Reported timing
At least 45 minutes before anticipated sexual activity
Reported frequency
As needed, at least 45 min before anticipated activity. Max 1 dose per 24 hours, max 8 doses per month.
Frequently discussed alongside
Based on community forum discussions. Not a recommendation to combine compounds.
Melanotan II
PT-141 is a metabolite of Melanotan II; both activate melanocortin receptors
Melanotan I (Afamelanotide)
All three are synthetic alpha-MSH analogs in the melanocortin family
Kisspeptin
Both discussed in contexts related to sexual function and hypothalamic signaling
Oxytocin
Both discussed in contexts of sexual desire and arousal pathways
Published research
Bremelanotide was evaluated in two randomized, double-blind, placebo-controlled phase III trials (RECONNECT, Studies 301 and 302) enrolling over 1,200 premenopausal women with HSDD. Both trials met their co-primary endpoints, demonstrating statistically significant improvement in sexual desire (eDiary) and reduction in distress (FSDS-DAO) compared to placebo. The drug's mechanism involves MC3R/MC4R activation in the CNS, increasing dopaminergic tone in the medial preoptic area. Pharmacokinetics show ~100% subcutaneous bioavailability, Tmax of ~1 hour, 21% protein binding, and elimination via urine (65%) and feces (23%). Nausea severity diminishes with repeated use (21% at first dose, ~3% thereafter).
Reported side effects
From community self-reports. Not from controlled studies.
Per FDA prescribing information: nausea (40%, most common reason for discontinuation), flushing (20%), injection site reactions (13%), headache (11%), vomiting (5%), cough (3%), fatigue (3%), paresthesia (3%), dizziness (2%). Transient blood pressure increase of ~6 mmHg systolic peaks 2-4 hours post-dose and resolves within 12 hours. Focal hyperpigmentation occurs in ~1% of patients and may not fully resolve. Contraindicated in uncontrolled hypertension or cardiovascular disease. 18% discontinuation rate due to adverse effects vs. 2% placebo.
Regulatory status
FDA (United States)
FDA-approved (June 21, 2019). NDA 210557. Marketed as Vyleesi for HSDD in premenopausal women. Not indicated for men, postmenopausal women, or sexual performance enhancement.
Health Canada
Not authorized as a therapeutic product. No DIN assigned.
WADA (Competitive Athletes)
Prohibited under S2 (Peptide Hormones, Growth Factors, Related Substances, and Mimetics) as a melanocortin receptor agonist.
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