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Melanocortin Peptide

Melanotan II

MT-2 • Synthetic Cyclic Alpha-MSH Analog

Melanotan II is an unapproved synthetic melanocortin peptide associated with skin darkening, appetite suppression, and sexual effects. Its broad receptor activity also produces significant side effects, and products sold online are not regulated for purity, potency, or sterility.

Route
SubQ
Compound type
Melanocortin agonist
Regulatory status
Not FDA approved
Last reviewed
At a glance

Melanotan II Quick Reference

Community loading
0.25–0.5mg daily
Often 7–14 days in unapproved community protocols
Maintenance
Members only
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Route
SubQ Injection
No approved MT-2 route or protocol
Primary effect
Pigmentation
Broader melanocortin activity also affects appetite and sexual response
Overview

What Is Melanotan II?

Melanotan II, or MT-2, is a synthetic cyclic heptapeptide modeled on alpha-melanocyte-stimulating hormone. It was developed during research into pigmentation and photoprotection, and early human studies reported tanning effects.

Unlike the more MC1-focused Melanotan I, MT-2 activates a broader range of melanocortin receptors. MC1 activity drives pigment production; central MC3/MC4 activity helps explain the appetite and sexual effects that appear alongside nausea, flushing, and yawning. Users cannot reliably separate the tanning effect from those other responses.

MT-2 remains unapproved for human use. Human studies are limited, products sold online are not regulated for identity or sterility, and a tan does not prevent skin cancer or make ultraviolet exposure safe.

Mechanism

Melanotan II Mechanism of Action

Alpha-MSH analog

A cyclic peptide designed to persist longer than native alpha-melanocyte-stimulating hormone.

MC1 signaling

Melanocyte MC1 activation promotes eumelanin production and visible skin darkening.

Central melanocortin activity

MC3 and MC4 signaling is associated with appetite and sexual responses.

Overlapping effects

Broad receptor activity also brings nausea, flushing, yawning, and other unwanted effects.

Research findings

Melanotan II Benefits

MT-2 has early human signals and extensive community use, but no approved indication or established long-term benefit.

Pigmentation

Early human studies and community reports describe skin darkening. Ultraviolet exposure is not required and adds independent risk.

Sexual Response

Reports include increased arousal and spontaneous erections; this effect is less predictable than a targeted treatment.

Appetite Effects

Reduced appetite is commonly reported, sometimes alongside nausea; this is not an approved weight-loss treatment.

Photoprotection Research

The original research goal involved pigment-related light protection, but MT-2 has not been shown to prevent skin cancer.

MT-2 vs. MT-1

MT-2 has broader receptor activity and a more burdensome side-effect profile than the more pigmentation-focused MT-1.

Protocol planning

Melanotan II Dosing Protocol

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Preparation

Melanotan II Reconstitution

Reconstitution Example

10mg vial + 2mL bacteriostatic water

Result5mg/mL

Reconstitution steps

1
Prepare

Wash your hands, clean the work surface, and wipe both vial stoppers with alcohol. Allow them to dry.

2
Add diluent slowly

Use a new sterile syringe and needle to direct the selected volume of compatible diluent down the inside wall of the vial.

3
Dissolve gently

Swirl or roll the vial until the contents dissolve; do not shake.

4
Storage

Store refrigerated at 2–8°C (36–46°F) and protected from light when the product instructions support this. Record the reconstitution date in your research journal.

N=1 reports

Melanotan II Community Experience

Self-reported anecdotal experiences aggregated from public & private peptide community discussions and anonymous peptideprotocols.app user reports. This information does not carry the same weight as published research.

Positive Reports

  • Visible darkening often appears within 1–3 weeks.
  • Some report increased arousal or spontaneous erections.
  • Reduced appetite is noticeable to some users.

Negative & Mixed Reports

  • Nausea, flushing, warmth, yawning, fatigue, and sometimes vomiting can be immediate.
  • Moles, freckles, and injection sites may darken; new or changing lesions need assessment.
  • The mix of tanning and sexual effects varies, and some find the experience unpleasant.
Stacking & synergy

Melanotan II Stacking & Synergy

No combination is established to improve MT-2 safety or tanning results. Its appetite and melanocortin effects make overlap especially relevant.

MT-2 + GLP-1 therapy

Appetite suppression and nausea may overlap, making under-eating, vomiting, or dehydration harder to manage.

MT-2 + PT-141

Both act on melanocortin pathways. Combining them may compound flushing, nausea, blood-pressure effects, or prolonged erections without an established advantage.

Consider MT-1 instead

For pigmentation-focused research, MT-1 has a narrower effect profile; it is a substitute, not a stack.

Safety notes

Melanotan II Side Effects & Safety

MT-2 has no approved human-use formulation. Acute side effects are common in reports, and the long-term safety of unregulated products is not established.

Seek urgent care for an erection lasting four hours or more, severe muscle pain with dark urine, reduced urination, chest pain, fainting, or persistent severe vomiting.

Commonly Reported Effects

  • Nausea, flushing, yawning, appetite reduction, fatigue, or chills.
  • Spontaneous erections and changes in sexual response.
  • Darkening of moles, freckles, and injection sites.

Serious Concerns

  • Priapism has been reported and requires emergency attention.
  • Serious muscle and kidney complications have appeared in case reports.
  • Changing skin lesions require dermatologic assessment; a causal melanoma risk remains uncertain.

Melanotan II Precautions

Avoid or Discuss With a Clinician If
  • Personal or family history of melanoma, atypical moles, or active skin cancer.
  • History of priapism or known hypersensitivity to product components.
  • Pregnancy or breastfeeding; human safety data are insufficient.
Use Caution With
  • Cardiovascular or blood-pressure conditions.
  • Kidney or liver disease.
  • Unverified product identity, potency, purity, or sterility.
MT-2 is not FDA approved for any human use. Skin darkening does not replace sunscreen, shade, clothing, or skin checks.
Final verdict

Peptide Protocols Verdict on Melanotan II

Not medical advice. This editorial is our own opinion piece based off the experience of our own lab rats.
Our opinionated opinion

We pretty much hate Melanotan II. It definitely tans you, but the nausea, occasional vomiting, random erections, appetite suppression, and mole changes make the tradeoff unattractive to us. We have heard enough rough experiences that we do not see a reason to reach for it when MT-1 exists.

MT-2 seems more potent to us, but its broader activity means you cannot isolate the tanning effect. We prefer MT-1 for pigmentation-focused research. Neither peptide makes UV exposure safe, and skin checks still matter. Our opinion on MT-2 remains a high avoid.