Melanotan II

Melanotan 2 is a synthetic non-selective melanocortin receptor agonist that activates MC1R, MC3R, MC4R, and MC5R. It is the most widely discussed tanning peptide in research and biohacker communities.

Melanotan 2 is the broad-spectrum cousin of Melanotan 1. It tans the skin via MC1R, but also touches receptors involved in appetite suppression and libido — which is why users report a wider set of effects.

Non-selectively activates melanocortin receptors. MC1R drives pigmentation. MC4R drives appetite and sexual signaling. MC3R/MC5R drive various secondary effects.

Synthetic melanocortin receptor agonist. Tanning + libido effects.

1. Melanotan II
2. CNS receptor systems (melanocortin, BDNF, GABAergic or sleep-regulating)
3. Neurotransmitter and neurotrophic signalling
4. Cognition, mood, sleep and libido research endpoints

A plain-English read on how much published evidence currently exists for Melanotan II. These ratings describe the volume and maturity of the literature — not effectiveness, safety, or suitability for any use.

Current limitations: most compounds in this category are studied in preclinical or small-sample settings. Absence of large controlled human trials is the single biggest limitation to keep in mind when reading any summary of Melanotan II.

Lyophilized compounds are supplied as a dry powder. Concentration is simply the total amount in the vial divided by the volume of bacteriostatic water added:

Concentration (mg/mL) = total mg in vial ÷ mL of diluent added

Commonly supplied vial sizes

10mg vial

Worked concentration example

10mg + 2mL BAC water → 5mg/mL On U-100 insulin syringe:

• • 5 units = 250mcg
• • 10 units = 500mcg
• • 20 units = 1mg

Run your own numbers with the reconstitution calculator — it converts vial size and diluent volume into mg/mL and mcg/mL.

The figures below are reported here descriptively, because they are the values most frequently cited in publicly available research literature and reference material. They are not instructions, not a protocol, and not a recommendation. These compounds are supplied for laboratory research use only and are not approved by the FDA for human consumption.

Commonly cited amounts

Loading: 250mcg daily for 1–2 weeks. Maintenance: 500mcg–1mg weekly.

Commonly cited frequency

Daily during loading; weekly maintenance

Commonly cited study duration

Ongoing while pigmentation maintained

Peptides are supplied freeze-dried because peptide bonds degrade far faster in solution than in a dry state. Understanding storage is part of understanding why the powder form exists at all.

• •Lyophilized powder: stored refrigerated, typically stable for months to years.
• •Reconstituted solution: refrigerated at 2–8°C, generally discussed as stable for roughly 30–60 days.
• •Heat and direct light accelerate degradation — vials are kept cool and dark.
• •Reconstituted material is not re-frozen; ice crystal formation disrupts peptide structure.
• •Bacteriostatic water contains 0.9% benzyl alcohol as a preservative, which is what allows multi-day storage after reconstitution.

More detail in the storage & handling guide and how peptide quality is evaluated.

• •Melanocortin receptor pharmacology
• •Pigmentation research
• •Appetite and sexual signaling studies
• •Comparison with Melanotan 1 and PT-141

Heavily discussed in tanning, libido, and appetite-suppression conversations. Common debate: tanning effects vs concerns about new moles and pigmentation changes.

“The non-selective tan + libido + appetite peptide.”

Used alone more often than stacked. Compared with PT-141 for libido focus and Melanotan 1 for selectivity.

Melanotan 2 is a non-selective melanocortin receptor agonist studied for pigmentation, appetite, and sexual signaling. Sold for laboratory research only.