α-MSH analogue (MC4)

PT-141

Cyclic α-MSH analogue approved as Vyleesi for hypoactive sexual desire disorder in premenopausal women.

Human RCT · t½ ~2.7 h · 1.75 mg, on-demand

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AHuman RCT evidenceHuman RCTα-MSH analogue (MC4)

Also: Bremelanotide · Vyleesi

Cyclic α-MSH analogue approved as Vyleesi for hypoactive sexual desire disorder in premenopausal women.

Scientific Consensus Engine

Evidence Intelligence Score

Heuristic — no indexed evidence yet
6.3/ 10
Overall confidence
Moderate
Outlook
Moderate
Evidence maturity
  1. Preclinical
  2. Pilot human
  3. RCT← current
  4. Multi-RCT
  5. Meta-analysis

Confidence aggregates eight dimensions of evidence — human data, safety maturity, mechanism, clinical readiness, momentum, consistency, long-term follow-up, and translational signal. It is a measure of what is known, not a recommendation. Methodology.

Eight-dimension breakdown
  1. Human evidence
    Weight of RCT and observational data
    8.8
  2. Safety maturity
    Follow-up depth and adverse-event signal
    6.9
  3. Mechanism confidence
    Pathway specificity and clarity
    6.3
  4. Clinical readiness
    Distance to physician-prescribable use
    7.8
  5. Research momentum
    Recency of indexed clinical evidence
    5.0
  6. Study consistency
    Effect direction across cohorts
    3.0
  7. Long-term data
    Follow-up beyond initial trial windows
    5.4
  8. Translational confidence
    Animal → human signal preservation
    7.6
Strongest supported claim

Effects on the indexed outcomes are supported by randomized human data, with 1 citation on file.

Weakest / unclear

Effect sizes outside trial populations and durations beyond the studied window remain less characterized.

Major unknowns

Interactions outside listed contraindications, long-term safety, and effect heterogeneity across age and sex are not fully resolved.

Scientific outlook

Outlook: maturing. Expect the consensus to harden as multi-site replications publish.

Mechanism
Melanocortin-4 receptor agonist; central pro-erectile/libido pathway.
Clinical evidence · 2 studies indexed

Erectile function

1 study

Libido & arousal

1 study
Observed research protocols · 2 regimens

Libido & arousal

1 regimen
FDA labelsource ↗

Most common AEs: nausea (40%), flushing, injection-site reactions, headache. Transient BP increase; contraindicated with uncontrolled hypertension or known CV disease.

Discontinue after 8 weeks if no improvement in HSDD symptoms per label.

Erectile function

1 regimen
Clinical trialsource ↗

Transient blood pressure elevation observed; intranasal program halted by sponsor in 2008.

Open-label safety/efficacy evaluation; intranasal program was discontinued in favor of SC formulation due to BP signals.

These are observed research regimens drawn from approved labels, clinical trials, or preclinical literature — not dosing recommendations. Suggestive, never prescriptive.

What we don't know yet
  • Long-term safety beyond reported study durations.
  • Effect size in populations under-represented in the cited trials.
  • Interactions with concomitant medications outside listed contraindications.

We surface uncertainty next to every claim. Suggestive, never prescriptive — discuss with a clinician.

Editorial team
Independent · No affiliate revenue
Reviewed quarterly
Brands carrying this peptide

3 brands across three tiers.

Medicine

1 brand

Regulator-approved finished medicines. Prescribed for specific indications, manufactured under GMP, distributed through licensed pharmacies.

Compounded (US 503A)

1 brand

Patient-specific preparations from US 503A compounding pharmacies. Require a valid prescription, not FDA-approved as finished drugs. Verify the pharmacy's licence and the active ingredient's status on the FDA 503A bulks list.

Research-use only

1 brand

Sold by chemical suppliers labelled 'for laboratory research only — not for human consumption'. No pharmaceutical-grade QC, no medical oversight. Listed for transparency.