TL;DR: Melanotan 2 comes in exactly one catalogue size — a 10mg vial. Reconstituted at PeptiMap’s reference volume of 2mL you land on 5 mg/mL, or 50 mcg per unit, which makes 250mcg a 5-unit draw, 500mcg a 10-unit draw and 1mg a 20-unit draw. Stretch the same vial to 5mL and you get 2 mg/mL, 20 mcg per unit — the identical peptide spread across a longer ruler, so every one of those draws multiplies by 2.5. Loading and maintenance doses differ in size, never in method. The grids below cover both volumes; the reconstitution calculator does the same arithmetic for any volume you prefer.
One vial size, two useful rulers
Melanotan 2 is unusual among the peptides on this site in that our catalogue lists a single format: the Melanotan 2 10mg vial. There is no 5mg to step down to and no 20mg to step up to, so every dosing question collapses into one decision — how much bacteriostatic (BAC) water you add.
Two volumes cover almost everything anyone actually does with this vial.
That last tile is the assumption everything below rests on, and it is worth stating once and clearly: all unit counts on this page are U-100 insulin-syringe units, where 100 units fill 1 mL and one unit is 0.01 mL. If your barrel is marked U-40 or U-50, the volumes are still right and the unit numbers are not.
The 2mL figure is not arbitrary — it is the reference volume printed on our own Melanotan 2 10mg page, and it is the volume most published protocol write-ups assume when they quote a dose in units without saying so. The 5mL figure exists because Melanotan 2 is dosed in micrograms from a milligram vial, and micrograms are where a fat concentration starts to hurt.
The two formulas behind every number here
Everything on this page is these two lines, applied over and over.
mg/mL = vial strength (mg) ÷ BAC water added (mL)
mcg per unit = (mg/mL × 1000) ÷ 100
Worked example, 10mg vial with 2mL:
- Concentration: 10 ÷ 2 = 5 mg/mL = 5000 mcg/mL
- Per unit: 5000 ÷ 100 = 50 mcg per unit
- A 500mcg draw: 500 ÷ 50 = 10 units = 0.10 mL
Worked example, the same 10mg vial with 5mL:
- Concentration: 10 ÷ 5 = 2 mg/mL = 2000 mcg/mL
- Per unit: 2000 ÷ 100 = 20 mcg per unit
- The same 500mcg draw: 500 ÷ 20 = 25 units = 0.25 mL
Same peptide, same 500 micrograms, same vial. Only the ruler changed.
10 units on a U-100 syringe = 0.10 mL = 500mcg when a 10mg vial sits in 2mL of BAC water.
The 10mg dose chart, at both reconstitution volumes
Two grids, one per volume. Doses per vial is the same in both because the amount of peptide never changed — only how thinly it is spread.
10mg vial + 2mL BAC water = 5 mg/mL (50 mcg per unit)
| Target dose | Draw volume | U-100 units | Doses per vial |
|---|---|---|---|
| 100 mcg | 0.02 mL | 2 units | 100 |
| 250 mcg | 0.05 mL | 5 units | 40 |
| 500 mcg | 0.10 mL | 10 units | 20 |
| 750 mcg | 0.15 mL | 15 units | 13.3 |
| 1 mg | 0.20 mL | 20 units | 10 |
10mg vial + 5mL BAC water = 2 mg/mL (20 mcg per unit)
| Target dose | Draw volume | U-100 units | Doses per vial |
|---|---|---|---|
| 100 mcg | 0.05 mL | 5 units | 100 |
| 250 mcg | 0.125 mL | 12.5 units | 40 |
| 500 mcg | 0.25 mL | 25 units | 20 |
| 750 mcg | 0.375 mL | 37.5 units | 13.3 |
| 1 mg | 0.50 mL | 50 units | 10 |
The pattern jumps out once you put the two side by side. At 2mL, a 100mcg dose is two units — two of the smallest tick marks on the barrel, where a half-unit misread is a 25% dosing error. At 5mL the same 100mcg is five units, and the same physical misread costs you 10%. That is the entire argument for the larger volume, and it is a measurement argument rather than a pharmacological one.
Going the other way, 5mL puts a 1mg draw at half a full barrel. Nothing wrong with that — it is still one draw — but if your working dose sits at 1mg you are carrying a lot of water for no benefit.
Same 10mg vial, same 500mcg target. Adding more BAC water spreads the dose across more units, which is what makes small draws easier to read accurately.
Loading versus maintenance: same method, different number
This is the point the four existing Melanotan articles on this site talk around without ever converting: there is no separate loading arithmetic. The two phases differ in dose size and frequency, not in how you get from micrograms to the plunger. You run the identical division either way.
Our loading and maintenance protocol guide sets out the ranges reported in the research literature. Converted at both reconstitution volumes, they read like this:
| Phase | Reported dose range | Units at 5 mg/mL | Units at 2 mg/mL |
|---|---|---|---|
| Loading, low start | 100–250 mcg | 2–5 units | 5–12.5 units |
| Loading, typical | 250–500 mcg | 5–10 units | 12.5–25 units |
| Maintenance | 500–1000 mcg | 10–20 units | 25–50 units |
Note the shape of it. Loading uses the smaller per-dose numbers but runs frequently; maintenance uses the larger per-dose numbers but runs once or twice weekly. That inversion catches people out, because “loading” sounds like it should mean the bigger syringe.
Run the weekly totals and it resolves:
- Loading at 250 mcg daily → 7 × 250 = 1750 mcg = 1.75 mg per week
- Loading at 500 mcg daily → 7 × 500 = 3500 mcg = 3.5 mg per week
- Maintenance at 500 mcg twice weekly → 1 mg per week
- Maintenance at 1 mg once weekly → 1 mg per week
The two maintenance patterns land on an identical weekly total by two different routes — ten units twice or twenty units once. Whichever you pick, the vial arithmetic is the same.
How long a 10mg vial actually lasts
Doses per vial is easy division. Days per vial is where it gets interesting, because two different limits compete.
| Pattern | Weekly peptide | Doses in 10mg | Calendar life |
|---|---|---|---|
| 250 mcg daily | 1.75 mg | 40 | ~40 days |
| 500 mcg daily | 3.5 mg | 20 | ~20 days |
| 500 mcg twice weekly | 1 mg | 20 | ~10 weeks |
| 1 mg once weekly | 1 mg | 10 | ~10 weeks |
Our 10mg vial page gives reconstituted storage at 2–8 °C for roughly 4–6 weeks. Compare that against the right-hand column and the conflict is obvious: at any maintenance pattern, a fully reconstituted 10mg vial outlives its own refrigerated window by about a month. At 250 mcg daily it fits, just about. At maintenance it does not.
There are two clean ways out, and both are arithmetic rather than judgement. Reconstitute the whole vial and accept that the tail of it sits past the stated window, or split the powder before adding water — 5mg in 1mL still gives you 5 mg/mL and the identical 50 mcg per unit, with the second half left lyophilised at -20 °C until you need it. The second option keeps every number on this page valid; you just halve the doses-per-vial column.
What a dose costs, in euros
Our EU peptide price index lists Melanotan 2 at one size and one price: 10mg at €49.99, which is €5.00 per mg. Because the vial only comes in one size, there is no per-mg ladder to climb and no bulk break to model — a rare case where the cost question has exactly one answer.
Per-dose, that works out to:
- 100 mcg → €0.50
- 250 mcg → €1.25
- 500 mcg → €2.50
- 1 mg → €5.00
Weekly, a 250 mcg daily loading pattern runs €8.75; either maintenance pattern runs €5.00. One vial covers a fortnight of loading at 250 mcg (3.5 mg, €17.50) with 6.5 mg left over — which is another way of saying the storage window, not the powder, is what you run out of first.
Worth noting for anyone weighing the melanocortin family against each other: the Melanotan 1 10mg vial and the PT-141 10mg vial are both listed at the same €49.99 in our snapshot. All three sit at €5.00 per mg, so price is not the variable that separates them — receptor selectivity is, and that is covered in Melanotan 1 vs Melanotan 2 and PT-141 vs Melanotan 2.
Where the numbers run out
Two things this chart deliberately does not tell you, because our data does not contain them.
Melanotan 1 is the contrast that makes the gap visible: it does have published human PK, and our dataset carries a terminal half-life of roughly 1–2 hours for the peptide itself alongside an apparent ~15 hours for the slow-release implant. Same family, completely different evidence depth.
The other thing worth reading before you commit to a schedule is what the pigment side of this actually does over time — our Melanotan and moles guide covers the darkening of existing nevi and freckles in detail, and there is no reason to duplicate it here. For the underlying melanocortin mechanism, what is Melanotan II is the background piece.
Hand it to the calculator
None of this needs re-deriving each time a dose changes. The reconstitution calculator takes vial strength, BAC volume and target dose and returns mg/mL, mcg per unit and the exact syringe mark; the Melanotan 2 calculator is pre-loaded with the 10mg vial. If you want to see how this vial compares against every other format on the site at a glance, the reconstitution chart puts them all on one page.
Frequently Asked Questions
How many units is 500mcg of Melanotan 2?
At the reference reconstitution — a 10mg vial in 2mL of BAC water, giving 5 mg/mL — 500mcg is 10 units on a U-100 syringe, or 0.10 mL. Reconstitute the same vial in 5mL instead and 500mcg becomes 25 units, because the concentration dropped to 2 mg/mL. The vial label never decides the unit count; the concentration does.
How much BAC water should I add to a 10mg Melanotan 2 vial?
2mL is our reference volume and gives clean whole-unit draws at every common dose: 5 units for 250mcg, 10 for 500mcg, 20 for 1mg. 5mL gives finer resolution for microgram work, at the cost of half-unit landings at 250mcg and 750mcg. Both are correct — it is a measurement-precision choice, not a potency one.
How many doses are in a Melanotan 2 10mg vial?
Ten milligrams is 10,000 micrograms, so it divides into 100 doses at 100mcg, 40 at 250mcg, 20 at 500mcg and 10 at 1mg. That is independent of reconstitution volume. The practical limit is usually the 4–6 week refrigerated window rather than the dose count.
Does the loading phase use different maths from maintenance?
No. Both phases use the same two formulas — vial strength divided by water added gives mg/mL, and that gives mcg per unit. The phases differ in dose size and frequency only. A 250mcg draw is five units at 5mg/mL whether you are loading or maintaining.
What is the Melanotan 2 dosis in units at 2mg/mL?
At 2 mg/mL (a 10mg vial in 5mL) each unit carries 20 mcg. So 100mcg is 5 units, 250mcg is 12.5 units, 500mcg is 25 units and 1mg is 50 units. The half-unit landings at 250mcg and 750mcg are the trade-off for the extra resolution.
Is there a smaller Melanotan 2 vial than 10mg?
Not in our catalogue — 10mg is the only listed size, and the only one carrying a price in our index (€49.99, or €5.00 per mg). If you want smaller working quantities, splitting the lyophilised powder before reconstitution is the route, since every concentration figure on this page scales proportionally.
References
- Dorr RT, Lines R, Levine N, et al. “Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study.” Life Sciences, 1996;58(20):1777-1784.
- Hadley ME, Dorr RT. “Melanocortin peptide therapeutics: historical milestones, clinical studies and commercialization.” Peptides, 2006;27(4):921-930.
- Ugwu SO, Blanchard J, Dorr RT, et al. “Skin pigmentation and pharmacokinetics of melanotan-I in humans.” Biopharmaceutics and Drug Disposition, 1997;18(3):259-269.
- Langan EA, Nie Z, Rhodes LE. “Melanotropic peptides: more than just Barbie drugs and sun-tan jabs?” British Journal of Dermatology, 2010;163(3):451-455.
- PeptiMap. “EU Peptide Price Index” — build-time snapshot of listed European research-supply pricing. The €49.99 figure and the €5.00 per mg derived from it come from that dataset, not from published literature.
This article is a research and educational reference only; Melanotan 2 is not an approved medicine, this is not medical advice, and it is not for human consumption.