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Skin & pigment

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α-MSH analog (non-selective MC agonist)

Melanotan II

Also known as: MT-2, MT-II, Melanotan-II, Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2

The popular community 'tanning peptide' — and the high-risk one. Serious safety flags: priapism, melanoma surveillance concerns, nausea, blood pressure effects. NOT the FDA-approved MT-1 / Scenesse molecule.

Reviewed 2026-05-04

What it does

Melanotan II (MT-2) is a synthetic cyclic 7-amino-acid analog of the natural hormone α-MSH. Unlike its sibling Melanotan I (which became the FDA-approved drug afamelanotide / Scenesse for a rare genetic light-sensitivity disorder), MT-2 was abandoned as a pharmaceutical candidate but became — and remains — one of the most heavily community-used research peptides on the gray market, primarily for its ability to drive deep cosmetic tanning. The same non-selective melanocortin-receptor activity that makes it a tanning agent also produces a meaningful safety burden: priapism (the same mechanism that makes the related compound bremelanotide / PT-141 effective for low sexual desire in women), nausea, blood pressure spikes, and changes in pigmented skin lesions that have raised melanoma surveillance concerns. Lead with the safety flags.

Used for

Dose

Starting
250 mcg · loading: every 1–2 days; maintenance: 1–2× weekly
Common
625 mcg · loading: every 1–2 days; maintenance: 1–2× weekly
Upper
1,000 mcg · loading: every 1–2 days; maintenance: 1–2× weekly
When
EveningSame logic as MT-1. Libido + appetite-suppression effects are more manageable at night than during work hours.
Site
subcutaneous (off-label / community)

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⚠ Caution

  • Personal or family history of melanoma or significant atypical-mole syndrome — STRONG contraindication; cases of melanoma developing during MT-2 use have been reported in the dermatology literature
  • Pre-existing erectile-priapism risk (sickle cell trait/disease, cavernosal pathology)
  • Uncontrolled hypertension (BP elevations reported)
  • Cardiovascular disease (BP and tachycardia effects)
  • Pregnancy and breastfeeding
  • Significant pre-existing pigmented lesions requiring monitoring
  • Hypersensitivity to peptide formulations or excipients

Your stack

Track this peptide in your protocol — dose, schedule, vials on hand, refill projection. Stays in your browser; no account needed.

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Use this peptide

Co-injection & overlap

Redundant with

  • Melanotan I — Both are α-MSH analogs driving MC1R-mediated melanogenesis; combining them doubles melanocortin-receptor load and adverse-event risk (nausea, BP, priapism) without additive tanning benefit.; typically run one, not both.
Reconstitution & storage

Lyophilized powder reconstituted with bacteriostatic water. A 10 mg vial in 5 mL BAC water = 2 mg/mL, making a 250 mcg dose ~12.5 units on a U-100 syringe. Use the Juno calculator to verify. Initial dose should be the lowest possible volume (~50 mcg) to assess tolerability.

Storage. Lyophilized: refrigerate. Reconstituted: refrigerate 2–8 °C, use within 30 days.

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Monitoring & questions

Reported side effects
  • Nausea, especially with initial doses (often significant)
  • Flushing, dizziness
  • Spontaneous penile erection / priapism (MC4R-mediated; can be prolonged and require medical intervention)
  • Increased blood pressure
  • New or darkened nevi (mole surveillance is essential during and after use)
  • Reports of melanoma developing during MT-2 use (causation vs surveillance bias contested; the signal warrants serious caution)
  • Yawning, drowsiness post-injection
  • Decreased appetite
  • Long-term safety in chronic recreational use is unknown
FAQ (2)

Reference

How it works

Non-selective agonist at all four melanocortin receptors expressed in skin and the CNS: MC1R (drives melanogenesis — the cosmetic tanning effect), MC3R / MC4R (modulates appetite, sexual function, and blood pressure — the source of the priapism, nausea, and BP effects), and MC5R (sebum, less clinically prominent). The non-selectivity is the key differentiator from MT-1 (more selective for MC1R) and from PT-141 / bremelanotide (developed specifically as a more selective MC4R agonist for sexual function).

Juno's take

This is the one with the safety story. Community popularity does not soften the risk profile, and the dermatology literature has reports of melanoma developing during MT-2 use — causation isn't proven, but the surveillance signal is real enough that dermatology specialists generally counsel against it for cosmetic tanning. The priapism is also not theoretical: the more-selective compound PT-141 exists precisely because MT-2's non-selectivity caused it. Worth knowing.

EvidenceTier 3 — Animal / in vitro

Tiers are per indication. The same molecule can be Tier 1 for one use and Tier 4 for another — the tier reflects published literature, not community framing.

Cosmetic tanning

Tier 3high confidence

MT-2 reliably drives melanogenesis in users — that biological effect is real and replicated in early-phase human work. Cosmetic tanning is not a regulator-approved indication, no controlled trial has established safe long-term dosing, and the safety burden (priapism, melanoma surveillance, BP, nausea) is substantial in a population using it for cosmesis rather than medical necessity.

Dorr RT et al. 1996Habbema L et al. 2017

Erectile / sexual function (community / off-label)

Tier 3high confidence

MC4R activation is clinically validated for sexual function via the related, more-selective drug bremelanotide / PT-141 (FDA-approved 2019 for HSDD in women). MT-2's non-selectivity drives meaningful adverse effects including priapism, which is the reason a more-selective compound was developed. Use of MT-2 for sexual function is mechanism-as-evidence with worse safety than the actually approved compound.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

Appetite suppression / weight loss

Tier 3medium confidence

MC4R activation suppresses appetite — MT-2 does cause meaningful early-dose anorexia. Not pursued clinically as a weight-loss agent (the GLP-1 class displaced this and other melanocortin approaches). Mechanism is real, clinical-outcome data is essentially absent.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

Citations (2)
  1. [1]
    Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study
    Dorr RT, Lines R, Levine N, et al. · Life Sciences · 1996 · PMID 8841168
    Anchor early Phase I work characterizing pharmacology and the priapism/nausea side-effect profile.
    View source
  2. [2]
    The use of melanotan injections for tanning: A literature review
    Habbema L, Halk AB, Neumann M, Bergman W. · Journal of Cosmetic Dermatology · 2017 · PMID 30171848
    Safety-focused literature review including reports of melanoma during MT-2 use; supports the cautionary editorial framing.
    View source