What is Melanotan II?
Before any melanotan 2 reconstitution math, it helps to know what is in the vial. Melanotan II is a synthetic research peptide modeled on alpha-melanocyte-stimulating hormone (alpha-MSH). It is a cyclic peptide: part of the chain is closed into a ring, which makes it shorter and more compact than the natural hormone. Its structure is written as Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2. It binds several melanocortin receptors rather than just one.
On labels and in searches it appears as Melanotan II, Melanotan 2, MT2 and MT-II. This page covers melanotan 2 reconstitution math only: how the water you add changes the concentration and how an amount you already have lines up with a U-100 syringe. It does not describe any use in people.
Melanotan II vs Melanotan 1: not the same compound
The two names look almost identical, but they are different molecules and should never be treated as interchangeable. Melanotan II is the small, cyclic version. Melanotan 1, also called afamelanotide, is a longer, linear chain of 13 amino acids that stays much closer to the natural hormone’s sequence. They bind melanocortin receptors differently, carry different regulatory histories and are sold in separately labeled vials.
For reconstitution math the formula is the same, but the inputs must come from the label of the compound you actually have. If your vial says Melanotan 1 or afamelanotide, use the Melanotan 1 reconstitution calculator instead of this page so the name, notes and chart match your product.
How much BAC water for a Melanotan 2 10mg vial?
Melanotan II is most often sold as a 10 mg vial of freeze-dried powder. The powder amount stays fixed; the water volume sets the concentration. The chart below shows micrograms per unit on a U-100 syringe for a 10 mg vial at several water volumes.
| BAC water | 10 mg vial |
|---|---|
| 1 mL | 100 mcg/unit 10 mg/mL |
| 2 mL | 50 mcg/unit 5 mg/mL |
| 3 mL | 33.33 mcg/unit 3.333 mg/mL |
| 5 mL | 20 mcg/unit 2 mg/mL |
Each cell shows mcg per unit on a U-100 syringe (100 units = 1 mL) and the resulting concentration.
More water means fewer micrograms in each unit, which spreads the same powder across more syringe marks. Volumes that divide evenly into 10 mg, such as 1, 2 or 5 mL, give round numbers that are easier to read and re-check. None of these volumes is a recommendation; the product labeling decides what goes into the vial. For every common vial size side by side, see the BAC water to peptide ratio chart.
Worked example: melanotan 2 10mg reconstitution in syringe units
The melanotan 2 reconstitution calculator above runs three steps. Vial mg ÷ water mL gives the concentration. The amount you enter ÷ that concentration gives the volume in mL. Volume in mL × 100 gives U-100 units. For example, if the amount you already have is 500 mcg, and the vial is 10 mg with 2 mL of water added:
The math: 10 mg ÷ 2 mL = 5 mg/mL (5,000 mcg/mL), which is 50 mcg per unit. 500 mcg ÷ 5,000 mcg/mL = 0.1 mL = 10 units on a U-100 syringe.
That figure is arbitrary, picked only because the math comes out clean. Watch the mg and mcg boxes: 1 mg = 1,000 mcg, so typing an amount in the wrong unit shifts the answer by a factor of 1,000. Units are the same size on every U-100 syringe, whether it holds 0.3 mL, 0.5 mL or 1 mL, and the U-100 syringe units to mL chart converts any reading back to mL.
Melanotan 2 reconstitution notes from suppliers
Most Melanotan II vials are described by suppliers as dissolving readily in water, but the product labeling controls the diluent, the volume and the storage conditions. Some suppliers specify bacteriostatic water; others list sterile water. Some suppliers specify adding the liquid slowly down the inside wall of the vial and swirling rather than shaking. How long the solution is kept after mixing and at what temperature depends on the product, so follow the label and a qualified professional.
- Record the water volume and the mixing date on the vial so the calculator matches what is inside.
- Bacteriostatic water contains 0.9% benzyl alcohol, which slows some bacterial growth but does not sterilize or replace aseptic technique.
- An opened multi-dose vial is commonly dated and discarded within 28 days unless the manufacturer specifies a different date.
For the general process behind these notes, read how to reconstitute peptides.
Is Melanotan II FDA-approved?
Melanotan II is not an FDA-approved drug. Vials sold online are labeled for research use only and carry no approved labeling, so identity, purity and sterility depend on the supplier. Two FDA-approved drugs do act on melanocortin receptors: bremelanotide (Vyleesi) and afamelanotide (Scenesse), both approved in 2019. Neither is Melanotan II, and neither approval extends to research-labeled MT2 vials.
A correct calculation cannot verify what is in a vial. It only shows how the label amount, the water you added and the syringe marks relate. To run the same math for other compounds, browse the peptide library.
Melanotan II FAQ
Is Melanotan 2 the same as Melanotan 1?
No. Melanotan II is a short cyclic peptide, while Melanotan 1 (afamelanotide) is a longer linear peptide. They are different compounds with different labels, so use the calculator page that matches your vial.
How much BAC water goes in a Melanotan 2 10mg vial?
There is no single correct amount. The water volume only changes the concentration. The chart on this page shows mcg per syringe unit for several volumes; the product labeling decides the diluent and volume.
What does the melanotan 2 reconstitution calculator show?
It shows the concentration in mg per mL, the liquid volume for an amount you enter, and the matching U-100 syringe units. It does not recommend any dose, schedule or frequency.
Is Melanotan II FDA-approved?
No. Melanotan II is not an FDA-approved drug. Research-labeled vials have no approved labeling.
Why does my result look 1,000 times too large?
That usually means the amount was entered in mg when it should have been mcg, or the reverse. Check the unit selector next to each field.