Melanotan II
Melanocortin Receptor Agonist (non-selective)Also known as: MT-II · Melanotan 2
A cyclic melanocortin analog with potent tanning, libido-enhancing, & appetite-suppressing effects via MC1R, MC3R, MC4R, & MC5R agonism.
Typical Dose
250–1000 mcg/day (loading); 250–500 mcg 3–5x/week (maintenance)
Route
Subcutaneous injection
Cycle
Loading: 2–4 weeks. Maintenance: as needed.
Half-life
~1–2 hours
Storage
Reconstituted: 2–8°C, use within 30 days. Keep away from light.
Overview
Melanotan II is a cyclic heptapeptide analog of alpha-MSH that acts as a non-selective agonist across multiple melanocortin receptors. MC1R activation drives melanogenesis (tanning) even without UV exposure. MC4R activation in the hypothalamus produces sexual arousal & appetite suppression (the same mechanism as PT-141). MC3R activation has metabolic effects.
Unlike PT-141 (Bremelanotide), which selectively avoids receptors producing nausea, Melanotan II activates a broader receptor profile & is associated with higher rates of nausea & facial flushing, particularly at higher doses. It is not FDA approved for any indication. Automatic spontaneous erections in men are a distinguishing feature at standard doses — less selective than PT-141's desire-focused effect.
Concerns about uneven & potentially abnormal mole changes with prolonged use have been raised. Users with numerous or atypical nevi should exercise caution given MC1R-driven melanocyte stimulation.
Quick Start Guide
Reconstitute with 1–2 mL bacteriostatic water per 10 mg vial.
Start with 100–250 mcg subcutaneously in the evening to assess tolerance (nausea is worst on the first dose).
Escalate to 500–1000 mcg/day for tanning loading. Maintain with 250–500 mcg 3–5x per week.
Sun or UV bed exposure is required for tanning — MT-II shifts melanocytes to the active state but UV initiates pigment transfer.
Research Indications
Skin tanning (melanogenesis)
Most EffectiveMC1R agonism drives melanocyte stimulation & eumelanin production. Produces tan with less UV exposure than natural tanning.
Sexual function & libido
Most EffectiveMC4R agonism in hypothalamus drives sexual arousal. In men: spontaneous erections are common at higher doses. Less selective than PT-141.
Appetite suppression
EffectiveMC4R & MC3R activation reduces appetite. Some weight loss observed alongside tanning protocols.
Research Protocols
Tanning (loading phase)
2–4 weeks; combine with moderate UV exposureDose
250–500 mcg
Frequency
Once daily pre-sleep (reduces nausea impact)
Route
SubQ abdomen
Maintenance
Ongoing as desiredDose
250–500 mcg
Frequency
3–5x per week
Route
SubQ
Sexual function (on-demand)
Dose
250–500 mcg
Frequency
2–4 hours before activity
Route
SubQ
Less selective than PT-141; nausea more likely at libido doses.
Peptide Interactions
Both are melanocortin agonists acting on MC4R for sexual function. Do not combine — additive nausea & MC4R overstimulation.
Side Effects & Safety
Common
- Nausea (very common on first dose; usually improves with repeated use)
- Facial flushing
- Spontaneous erections in men
- Darkening of existing moles
- Appetite suppression
Uncommon
- Yawning
- Lethargy
- New mole formation or changes to existing nevi
- Hyperpigmentation in skin creases
When to Stop
- Any concerning mole changes — consult dermatologist
- Signs of allergic reaction
- Hypersensitivity in patients with Fitzpatrick skin type I (very fair skin)
How to Reconstitute
Wipe stopper with alcohol.
Draw 2 mL bacteriostatic water into syringe.
Inject slowly down inner vial wall.
Swirl gently — do not shake.
Label & refrigerate. Store away from light.
Dosing math: 2 mL BAC water per 10 mg vial = 5000 mcg/mL. For 500 mcg: 0.1 mL. For 250 mcg: 0.05 mL.
Quality Indicators
Good — use as normal
- Clear, colorless solution
Acceptable
- Very faint yellowish tint
Discard immediately
- Persistent cloudiness
- Particulate
- Brown discoloration
What to Expect
Day 1–3
Nausea & flushing most pronounced. Libido effects begin immediately. Spontaneous erections in men at standard doses.
Week 1–2 (loading)
Progressive darkening of skin with UV exposure. Existing moles may darken. Nausea typically reduces after first week.
Week 3–4 (loading)
Near-full tanning effect achieved with regular UV. Transition to maintenance dosing.
Maintenance
2–3 injections/week sustain tan. Less UV exposure needed versus natural tanning.
Community Insights
Self-reported. Reflects user experience, not clinical outcomes.
Research References
International Journal of Impotence Research · 2003
Double-blind crossover trial showing significant improvement in erectile function with MT-II vs placebo.
doi:10.1038/sj.ijir.3901006 →Verify what you have
Information on this page applies to pharmaceutical-grade peptides. Purity & identity of research-grade products vary. Certipep provides independent ESI-TOF-MS & HPLC analysis with a signed analytical report.
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