Melanotan II
Melanotan II (MT-II)
Tanning and libido through the melanocortin system
A synthetic analog of alpha-MSH that activates the melanocortin receptors, driving skin pigmentation (tanning) through MC1R and sexual arousal and appetite suppression through MC4R. Its dual action — and a tendency to cause nausea and existing-mole darkening — makes individual response highly genotype-dependent.
- Half-life
- ~33 hours
- Route
- Subcutaneous injection
- Typical dose
- 0.25–0.5 mg (titrate up)
- Availability
- Research-only
Key Benefits
Increased skin pigmentation with less UV exposure
Enhanced libido and sexual arousal
Mild appetite suppression
Effects centrally mediated, not blood-flow dependent
Low doses often sufficient in responders
Mechanism of Action
How Melanotan II works
Melanotan II is a broad melanocortin-receptor agonist:
- MC1R activation (pigmentation) — stimulates melanocytes to produce eumelanin, increasing tanning with less UV exposure. The strength of this response is tightly tied to your MC1R genotype.
- MC4R activation (libido & appetite) — engages central MC4R pathways that increase sexual arousal and suppress appetite, the basis for its libido and mild weight effects.
- Non-selectivity — because it hits multiple melanocortin receptors, it commonly causes nausea, flushing and darkening of existing moles and freckles.
- Central nervous action — the arousal effect is centrally mediated, distinct from blood-flow agents, and overlaps mechanistically with PT-141 (a related melanocortin peptide).
Your Genetics & Melanotan II
Genetic variants that affect your response
These SNPs determine how effectively Melanotan II works for you specifically. A genetic peptide report identifies your variants before you start.
The R151C red-hair-associated variant reduces MC1R signaling toward eumelanin. Carriers (often fair-skinned, red-haired) tan poorly even with Melanotan II, since the receptor it targets for pigmentation signals weakly.
Variants near MC4R alter central melanocortin signaling. This influences how strongly Melanotan II drives the libido and appetite-suppression effects, which run through MC4R rather than MC1R.
OCA2 is central to melanin production. Variants here shape baseline pigmentation capacity and therefore how visible a tanning response is once MC1R is stimulated.
The Val158Met variant changes how quickly catecholamines are cleared, which can modulate the nausea and flushing many users experience with melanocortin agonists like Melanotan II.
Which variants do you carry?
Upload your DNA data or order a kit to find out.
Evidence & Research
25+
Published studies
Published human or robust animal studies with clear mechanistic rationale
Sourcing & access
Where to buy Melanotan II
Melanotan II is sold as a research compound, not a licensed medicine, so quality and legal status vary widely by country and vendor. If you're sourcing it, treat independent purity testing as non-negotiable.
- Insist on a recent third-party Certificate of Analysis (COA) for the exact batch — labs like Janoshik verify purity and identity.
- Check the legal status where you live before ordering — it differs from country to country.
- Reconstitute correctly with bacteriostatic water and start at a conservative dose.
Swiss Chems is a US research-chemical supplier that publishes third-party Certificates of Analysis. Sold for research use only — check your local laws.
Before you buy: see whether your DNA actually responds to Melanotan II, and at what dose. Analyze my DNA — $99 →
Educational information only, not medical advice. Some outbound links are affiliate links (disclosed, at no extra cost to you), and providers we partner with are listed first. Most peptides are not FDA-approved — consult a qualified professional and check your local laws before purchasing.
Common Stacks
Melanotan II is commonly combined with:
PT-141
Sexual Health StackStrong EvidencePT-141 (Bremelanotide)
A melanocortin receptor agonist, FDA-approved as Vyleesi for low sexual desire (HSDD) in premenopausal women and used off-label for libido in both sexes. Unlike Viagra-type drugs that work on blood flow, PT-141 acts centrally in the brain to raise sexual desire itself — a fundamentally different mechanism. Taken on-demand by subcutaneous injection.
Frequently Asked Questions
Why do some people barely tan on Melanotan II?
Tanning runs through MC1R, the melanocortin-1 receptor. People carrying loss-of-signal MC1R variants (commonly fair-skinned or red-haired individuals) have a receptor that signals weakly toward pigment, so even with Melanotan II the tanning response is muted. Your MC1R genotype is the main predictor.
How is Melanotan II related to PT-141?
PT-141 (bremelanotide) is a closely related melanocortin peptide derived from the same family. Both act centrally on melanocortin receptors for arousal, but PT-141 is more selective for the sexual-arousal pathway, while Melanotan II also drives pigmentation through MC1R.
Does genetics affect Melanotan II response?
Yes, strongly. MC1R variants determine the tanning response, MC4R variants shape libido and appetite effects, OCA2 sets baseline pigment capacity, and COMT influences nausea and flushing. A genetic peptide report profiles these so you know what to expect before starting.
Learn More About Melanotan II
Your next move
Two ways forward with Melanotan II.
Not sure it's for you?
Will Melanotan II work for your genes — and at what dose?
Your report scores Melanotan II against your receptor, CYP and pathway variants — likely responder, non-responder, and a sensible starting dose — in minutes.
Analyze my DNA — $99Already decided?
Get Melanotan II from Swiss Chems.
A US research-chemical supplier with third-party Certificates of Analysis. Sold for research use only — check your local laws before ordering.
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