Melanotan II
Non-selective melanocortin agonist — potent tanning and sexual effects, but significant safety concerns vs. PT-141.
Research facts
| Half-life | ~1h |
|---|---|
| Route | SubQ / Nasal |
| Typical dose | 0.25–0.5 mg |
| Frequency | Daily (loading), then maintenance |
| Solvent | Bacteriostatic water |
| pH | 5.5–7.5 |
| Stability | 30 days at +4°C |
Mechanism of action
Melanotan II is a synthetic cyclic analogue of alpha-MSH that activates all 5 melanocortin receptor subtypes (MC1R–MC5R). MC1R activation drives melanin production (tanning effect); MC3R and MC4R activation produces sexual arousal and appetite suppression (shared mechanism with PT-141); MC5R activation stimulates exocrine glands. The non-selective activation profile is the key difference vs. PT-141 (which is the MC3R/MC4R-selective fragment). MC1R activation causes hyperpigmentation (tanning) and importantly can stimulate melanocyte growth — raising theoretical melanoma risk with chronic use.
Documented effects (research-model)
- Intense tanning response (melanin stimulation)
- Strong sexual arousal (MC3/MC4R activation)
- Appetite suppression
- Originally developed for skin cancer prevention (paradoxical given melanoma concerns)
Research protocols
| Protocol | Dose | Frequency | Cycle | Vial |
|---|---|---|---|---|
| Not recommended for research | 0.25–0.5 mg SubQ | Daily loading then maintenance | Loading protocol varies | 10mg / 10mL BAC water |
Research context only. Not medical advice. Consult a qualified healthcare professional before any protocol decision.
Synergies
No documented synergies in the current reference set.
Myths & misconceptions
Evidence gaps
- Melanoma risk with chronic use not quantified in controlled studies.
- MC5R activation effects on exocrine function not well characterised.
- Long-term receptor desensitisation profile.
Safety notes
NOT RECOMMENDED over PT-141 due to non-selective receptor profile. MC1R activation concerns: promotes melanocyte activity, nausea is common (MC3/4R), spontaneous erections. Avoid in individuals with personal or family history of melanoma or atypical naevi. Research use with significant caution.
Biomarkers to monitor
Primary-source citations
- PMID 15733055 — Melanocortin agonists, melanoma and the melanocyte risk (Pigment Cell Res. 2005)
Frequently asked
What is Melanotan II?
Melanotan II (MT-II — Non-Selective Melanocortin Agonist) is a research compound classified in our library as Tier D — Animal or in-vitro data only.. Non-selective melanocortin agonist — potent tanning and sexual effects, but significant safety concerns vs. PT-141.
What is the evidence tier for Melanotan II?
We classify Melanotan II as Tier D: Animal or in-vitro data only. See our full peptide evidence tiers explainer for how we assign S/A/B/C/D.
What is the research dose of Melanotan II?
For Melanotan II, typical research dose is 0.25–0.5 mg, route is SubQ / Nasal, half-life is ~1h. Protocols vary by research goal — see the protocols section on this page for standard and advanced dosing schedules. Research use only, not medical advice.
Is Melanotan II safe?
NOT RECOMMENDED over PT-141 due to non-selective receptor profile. MC1R activation concerns: promotes melanocyte activity, nausea is common (MC3/4R), spontaneous erections. Research context only — no compound on this site is approved for human therapeutic use unless explicitly noted.