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Specimen Atlas of Research Peptides30 plates · MIT
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XIVPlate XIVReviewed 2026-04-25

Melanotan-II

α-MSH Analog (cyclic heptapeptide)

also known as MT-II, MT2, Melanotan 2

Synthetic cyclic heptapeptide derived from α-MSH (Ac-Nle-Asp-His-D-Phe- Arg-Trp-Lys-OH cyclic). Activates multiple melanocortin receptors — MC1R drives skin pigmentation, MC4R drives sexual arousal pathways. Distinct from PT-141 / bremelanotide which is more MC4R-selective. Not FDA-approved; widely used informally for tanning.

§ I

At a glance

Per dose
0.25–1.0 mg
[dorr-1996-mt2]
Evidence level
Phase 1
[dorr-1996-mt2]
Half-life
~1 hr
Route

SQ · Abdomen · Loading 5–7 days, then maintenance

§ II

Mechanism

Primary target — MC1R (skin) + MC3R + MC4R (CNS sexual / appetite) [dorr-1996-mt2].

Pathway — MC1R agonism → melanocyte tyrosinase → eumelanin synthesis. MC4R → autonomic sexual arousal centres [dorr-1996-mt2][simerly-2023].

Downstream effect — Skin darkening, photo-protection, increased sexual desire / spontaneous erection [dorr-1996-mt2].

Origin — Cyclic 7-AA modified α-MSH analog; designed at University of Arizona [dorr-1996-mt2].

§ III

Dosage

Protocols described in the cited literature; not medical advice.

ParameterValue
Loading phase0.25–0.5 mg/day SQ × 5–7 days [dorr-1996-mt2]Builds up to visible tan.
Maintenance0.5–1.0 mg 1–2×/weekAfter visible tan develops; supports with UV exposure.
FrequencyDaily during loading; 1–2× per week maintenance
Lower / starter dose0.1 mg / dayConservative starter — assess tolerability for nausea.
Evidence basisPhase 1 + anecdotal [dorr-1996-mt2]
Duration8–12 weeks per cycle
ReconstitutionBacteriostatic water; protect from light
TimingEvening preferred (24h tan-development cycle)
Half-life~1 hour plasma; effects on melanocytes persist days
§ III · b

Reconstitution

A pure mass-to-volume utility. Enter what you have in the vial; the atlas computes the volume per dose. No prescription information.

Inputs
The calculator does pure mass-to-volume math. It does not recommend a dose. Refer to Melanotan-II's cited literature for protocol specifics.
Volumetric outputFig. C — reconstitution math
Volume per dose
0.500mL
≈ 50.0 units on a U-100 insulin syringe
Concentration
500
mcg per mL
Doses per vial
4
at this dose
§ V

Adverse events

Severities follow the FDA / CTCAE convention.

Nauseamoderate
Common, especially loading phase
Flushingmild
Common transient
Spontaneous erectionmild
Common in men — MC4R cross-effect [dorr-1996-mt2]
Increased mole / freckle pigmentationmoderate
Existing moles darken; new lesions possible
Melanoma risksevere
Theoretical concern — increased melanocyte activity; CAUTION in melanoma history
Appetite suppressionmild
MC4R-mediated; mild
Pregnancy / OBsevere
Contraindicated
Absolute contraindications
  • — History of melanoma or atypical mole syndrome
  • — Pregnancy / breastfeeding
  • — Active uncontrolled hypertension
Relative contraindications
  • — Significant freckling / dysplastic nevus
  • — Personal or family melanoma history
§ VI

Administration

  1. 01
    Reconstitution

    Add 2 mL bacteriostatic water to 10 mg vial → 5 mg/mL = 500 mcg per 0.1 mL. Light-protected.

  2. 02
    Injection site

    SQ — abdomen. Rotate sites.

  3. 03
    Timing

    Evening preferred. UV exposure (sunlight or tanning bed) helps develop tan.

  4. 04
    Storage

    Lyophilised: refrigerate, light-protected. Reconstituted: refrigerate ≤30 days.

  5. 05
    Needle

    29–31G insulin syringe.

Appendix

Sources

21%

of 43 rendered claims carry a resolvable citation.

  1. [dorr-1996-mt2]
    Dorr 1996 — Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide
    Life Sci, 1996
    PubMed →
  2. [simerly-2023]
    Simerly 2023 — Bremelanotide (PT-141): clinical pharmacology + safety review
    Sex Med Rev, 2023
    Source →
Plate composed 2026-04-25 · maturity reviewed · schema v1 · Contributors: peptidesdb-core · 34 fields uncited — open contributions
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