Melanotan II Reconstitution Guide: Mixing, Dosing & Storage

Melanotan II (MT-2) is one of the more unique peptides in the research landscape — a synthetic analog of alpha-melanocyte-stimulating hormone (α-MSH) that interacts with melanocortin receptors throughout the body. It’s been studied for its effects on pigmentation, appetite, and other melanocortin-mediated pathways.

Reconstituting Melanotan II is straightforward, but the peptide has one critical storage requirement that catches beginners off guard: it’s highly light-sensitive. This guide covers everything from reconstitution to dosing math, with special attention to protecting your solution from degradation.

Quick Summary

• Peptide type: Alpha-MSH analog (melanocortin receptor agonist)
• Common vial size: 10 mg lyophilized powder
• Typical research doses: 250–500 mcg (loading: daily; maintenance: 2x/week)
• Reconstitute with: Bacteriostatic water
• Storage after reconstitution: 2–8°C for up to 28 days — wrap vial in foil (light-sensitive)
• Half-life: ~33 minutes
• Route: Subcutaneous injection
• Use our Peptide Reconstitution Calculator for instant dosing math

What Is Melanotan II?

Melanotan II is a cyclic heptapeptide — a ring-shaped chain of 7 amino acids — that was originally developed at the University of Arizona in the 1990s. It’s a synthetic analog of α-MSH, the body’s natural melanocyte-stimulating hormone.

MT-2 acts on several melanocortin receptors:

• MC1R — involved in melanin production and skin pigmentation
• MC3R — involved in energy homeostasis and feeding behavior
• MC4R — involved in appetite regulation and sexual function
• MC5R — involved in sebaceous gland function

This broad receptor affinity means Melanotan II has been studied across multiple research areas, including pigmentation biology, appetite regulation, and sexual function research. It’s a non-selective melanocortin agonist — it hits multiple receptor subtypes, which accounts for its wide range of observed effects in research.

Key Characteristics

• Molecular weight: 1,024.18 g/mol
• Sequence: Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-NH₂ (cyclic)
• CAS number: 121062-08-6
• Appearance: White lyophilized powder
• Solubility: Readily soluble in bacteriostatic water
• Half-life: Approximately 33 minutes (short — but effects persist longer due to receptor binding kinetics)

How Melanotan II Is Supplied

MT-2 is sold as a lyophilized powder in glass vials. The standard size:

• 10 mg per vial — by far the most common
• 5 mg per vial — occasionally available

Before reconstitution, store lyophilized MT-2 at -20°C (freezer) for long-term stability. The unreconstituted powder is much more stable than the solution, but should still be kept away from light.

How to Reconstitute Melanotan II

What You’ll Need

• Melanotan II vial (10 mg)
• Bacteriostatic water
• 1 mL insulin syringe for adding water
• 0.5 mL or 0.3 mL insulin syringe for dosing
• Alcohol swabs
• Aluminum foil (for wrapping the reconstituted vial)

Choosing Your Water Volume

For a 10 mg vial, here are common options:

Recommended: 2 mL of BAC water into a 10 mg vial. This gives you 5,000 mcg/mL (5 mg/mL), putting a 500 mcg dose at an easy-to-read 10 units on an insulin syringe. The 1 mL option works but requires very small syringe volumes (2.5 units for 250 mcg) that can be hard to measure accurately.

Step-by-Step Reconstitution

1. Remove the flip-off cap from the MT-2 vial
2. Swab both stoppers with alcohol wipes
3. Draw 2 mL of BAC water into a syringe
4. Insert the needle through the vial stopper, angling toward the glass wall
5. Slowly add the water — let it trickle down the side of the vial over 20–30 seconds
6. Remove the needle and set the vial on a flat surface
7. Swirl gently. MT-2 dissolves quickly — usually within 30–60 seconds
8. Inspect. The solution should be clear. A very slight yellow tint is normal for MT-2 — this is not degradation
9. Immediately wrap the vial in aluminum foil. This is not optional. MT-2 degrades when exposed to light

For the full reconstitution process with technique tips, see our peptide mixing guide.

Melanotan II Dosing Protocol

MT-2 research protocols typically use a two-phase approach: a loading phase to establish saturation, followed by a maintenance phase at reduced frequency.

Loading Phase

• Dose: 250–500 mcg per day
• Duration: 2–3 weeks (varies by protocol)
• Frequency: Once daily, typically in the evening
• Purpose: Build up melanocortin receptor stimulation

Some protocols start at 250 mcg for the first few days, then increase to 500 mcg once tolerance is assessed. Starting at the lower end helps identify sensitivity.

Maintenance Phase

• Dose: 500 mcg
• Frequency: 2 times per week
• Duration: Ongoing for the duration of the study
• Purpose: Maintain receptor stimulation with less frequent dosing

Worked Dosing Example

Setup: 10 mg vial reconstituted with 2 mL bacteriostatic water.

Concentration: 10 mg ÷ 2 mL = 5 mg/mL = 5,000 mcg/mL

Total doses available: 10,000 mcg ÷ 500 mcg = 20 doses at 500 mcg

• 250 mcg dose: 250 ÷ 5,000 = 0.05 mL = 5 units
• 500 mcg dose: 500 ÷ 5,000 = 0.1 mL = 10 units

Vial longevity during loading: At 500 mcg/day, one 10 mg vial lasts 20 days — nearly the entire loading phase from a single vial.

Vial longevity during maintenance: At 500 mcg twice per week (1,000 mcg/week), one 10 mg vial lasts 10 weeks — well beyond the 28-day reconstituted stability window. This means you’ll likely discard remaining solution before it’s used. Consider using less water (1 mL) or splitting with other researchers.

For more on syringe units and measurement, see our detailed guide.

Storage: Light Sensitivity Is Critical

This is where Melanotan II differs from most peptides. MT-2 contains a tryptophan residue and other light-sensitive amino acids that degrade when exposed to UV and visible light. Degradation products can be inactive or potentially problematic for research validity.

Storage Rules for MT-2

• Refrigerate at 2–8°C immediately after reconstitution
• Wrap the vial in aluminum foil — this is the single most important storage step
• Stability window: Up to 28 days refrigerated and protected from light
• Never freeze reconstituted solution
• Unreconstituted powder: Store at -20°C, also wrapped or in a lightproof container
• Minimize time outside the fridge — draw your dose and return the vial promptly

What Light Degradation Looks Like

A reconstituted MT-2 solution that has been light-exposed will gradually:

• Develop a darker yellow or amber color
• Lose potency over time
• Potentially form precipitate in advanced degradation

If your clear/slightly-yellow solution turns noticeably darker, it’s degrading. Discard it.

For more storage guidance, see our peptide storage guide.

Injection Guidance

Melanotan II is administered via subcutaneous injection, typically in the abdomen.

• Injection sites: Abdomen is most common; outer thigh is an alternative
• Timing: Many protocols call for evening dosing
• Needle gauge: 29–31 gauge insulin syringes
• Injection volume: Very small — 5–10 units for standard doses, making injection comfortable

The very short half-life (~33 minutes) of MT-2 means the peptide is rapidly cleared from circulation, but its effects persist because it binds to melanocortin receptors and triggers intracellular signaling cascades that outlast the peptide’s presence in the blood.

For injection technique details, see our subcutaneous injection guide.

Practical Tips for Melanotan II Research

Start low. The 250 mcg starting dose during loading isn’t just protocol — nausea is the most commonly reported acute effect, and starting low helps assess individual sensitivity before moving to 500 mcg.

Foil wrap immediately. Don’t tell yourself you’ll do it later. Wrap the vial in foil right after reconstitution. Even 30 minutes of light exposure starts the degradation clock.

Match vial size to usage rate. During maintenance (1,000 mcg/week), a 10 mg vial lasts 10 weeks — but it’s only stable for 4 weeks once reconstituted. You’ll waste peptide. Consider smaller vials or a reconstitution volume that concentrates the solution for faster use.

Use a 0.3 mL syringe for precision. At 5 units per dose (250 mcg), a standard 1 mL (100-unit) syringe can be hard to read accurately. A 0.3 mL (30-unit) syringe has finer graduations and better precision for these small volumes.

Note the short half-life. MT-2’s ~33-minute half-life is among the shortest of commonly researched peptides. The effects outlast the circulating peptide, but this pharmacokinetic profile is important for researchers to understand when designing protocols.

Calculate Your Exact Dose

Whether you’re using a 5 mg or 10 mg vial, loading or maintenance dosing, our calculator handles the math.

Try our free Peptide Reconstitution Calculator to calculate your exact Melanotan II dosing.

This content is for educational and research purposes only. Melanotan II is a research compound. Always follow applicable regulations and consult with qualified professionals regarding research protocols.