Melanotan II Calculator

What Is Melanotan II?

Melanotan II (MT-II) is a synthetic cyclic heptapeptide and a superpotent analog of alpha-melanocyte stimulating hormone (alpha-MSH), an endogenous messenger belonging to the melanocortin family. The natural alpha-MSH sequence was truncated and chemically stabilized with a ring-forming lactam bridge. This cyclization protects the molecule from enzymatic degradation and gives it markedly higher potency and a longer duration of action than the unstable native hormone. Melanotan II was originally developed at the University of Arizona in the 1980s, with the goal of researching a "sunless tanning" agent capable of inducing skin pigmentation without prior UV exposure.

Unlike Melanotan I, which acts more selectively at the melanocortin-1 receptor (MC1R), Melanotan II is a non-selective pan-agonist and binds to multiple melanocortin receptor subtypes, including MC1R, MC3R, MC4R, and MC5R. This broader receptor activation produces the two effect groups most frequently described in research: pronounced stimulation of melanin production (pigmentation) via MC1R, and an influence on central nervous pathways linked to appetite regulation and sexual arousal via MC3R and MC4R. This dual profile fundamentally distinguishes Melanotan II from simpler "tanning peptides."

Melanotan II is not an approved drug. It is traded strictly as a research-use compound. The observations summarized here come predominantly from preclinical work and from early, small Phase I studies (such as Dorr and colleagues, Life Sciences 1996, and Wessells and colleagues, Urology 2000). Robust long-term human data is largely absent, so every consideration remains within a research framing.

Mechanisms of Action

Melanotan II exerts its effects exclusively through activation of melanocortin receptors, a family of G-protein-coupled receptors. Each subtype mediates a distinct biological signal:

• MC1R agonism and melanogenesis: The melanocortin-1 receptor sits on the skin's melanocytes. Its activation increases the activity of the enzyme tyrosinase and shifts pigment production from reddish-yellow pheomelanin toward dark-brown eumelanin. The result is a UV-independent deepening of skin pigmentation, considered the central feature of Melanotan II in research.
• MC4R agonism and appetite regulation: The melanocortin-4 receptor in the hypothalamus is a key regulator of hunger and energy balance. Its stimulation by Melanotan II is associated with reduced food intake and explains the appetite-suppressing effect observed in preclinical models.
• MC3R/MC4R and sexual arousal: Through central melanocortin pathways, Melanotan II produces pro-erectile and libido-enhancing effects in animal models and small studies. This mechanism formed the basis for the development of the related, more selective peptide bremelanotide.
• MC5R and exocrine glands: The melanocortin-5 receptor is associated with the function of sebaceous and sweat glands, among others. Its co-activation is discussed as a possible factor in occasionally reported skin reactions.
• Inflammatory modulation: Melanocortins generally possess inflammation-modulating properties. For Melanotan II, however, this component is far less characterized than the pigmenting and central nervous effects.

Dosage Calculation

In research practice, Melanotan II is not used at a full dose immediately but is introduced gradually through a loading phase. Because of its pronounced effects on pigmentation and appetite, it is customary to begin at the low end of the range and increase the dose stepwise until a stable maintenance state is reached.

Standard Dosing Parameters

• Starting/loading dose: 0.1 mg (100 mcg) per administration
• Standard dose: 0.25 mg (250 mcg) per administration
• Higher range: 0.5–1.0 mg (500–1,000 mcg) per administration
• Frequency: Loading phase often daily; maintenance phase typically 2–3 times per week
• Half-life: approximately 2 hours (literature estimate)
• Typical syringe: 0.3 mL insulin syringe (29–31 gauge, 6–8 mm needle)

Example Calculation: 10 mg Vial with 2 mL BAC Water

A common vial size is 10 mg. Adding 2 mL of bacteriostatic water gives a concentration of 5 mg/mL (5,000 mcg/mL).

• 0.10 mg dose: 100 ÷ 5000 = 0.02 mL (2 units on a U100 syringe)
• 0.25 mg dose: 250 ÷ 5000 = 0.05 mL (5 units)
• 0.50 mg dose: 500 ÷ 5000 = 0.10 mL (10 units)
• 1.00 mg dose: 1000 ÷ 5000 = 0.20 mL (20 units)

At a maintenance dose of 0.25 mg, a 10 mg vial provides 40 administrations. The very small volumes at low doses can be hard to read accurately, so it can be useful to use more BAC water to lower the concentration and enlarge the readable volume. Use the Melanotan II calculator above to compute exact volumes and units for any vial size, reconstitution volume, and target dose.

Reconstitution

Melanotan II is supplied as a lyophilized (freeze-dried) powder in sealed vials and must be reconstituted with bacteriostatic water (BAC water) before use. BAC water contains 0.9% benzyl alcohol, which inhibits microbial growth and extends the usable window of the dissolved solution. Sterile water for injection is less suitable for multi-dose vials.

Step-by-Step Reconstitution Protocol

1. Gather supplies: Melanotan II vial, bacteriostatic water vial, alcohol swabs, a sterile draw needle (18–21 gauge), and your insulin syringe for administration.
2. Wipe the rubber septa of both vials with fresh alcohol swabs and allow them to air-dry for 30 seconds. Do not blow on the septa or touch them after cleaning.
3. Draw the desired volume of BAC water (2 mL is standard for a 10 mg vial) into the draw syringe.
4. Insert the needle into the peptide vial at an angle, directing the tip toward the inner glass wall rather than the lyophilized powder. A direct jet onto the powder cake can shear peptide bonds and damage the molecule.
5. Slowly push the plunger, allowing BAC water to run down the inside wall of the vial and gently wet the powder from below.
6. Gently swirl or roll the vial between your palms until the powder is completely dissolved. The solution should appear clear and colorless. Do not shake or vortex the vial.
7. Label the vial with the reconstitution date and concentration (e.g., "Melanotan II 5 mg/mL — reconstituted [date]").

If the solution appears cloudy, discolored, or contains visible particulate matter, discard the vial and do not use it.

Storage and Shelf Life

• Lyophilized powder (unreconstituted): Store at −20°C for long-term storage (stable for 24+ months). Short-term storage at 2–8°C (refrigerator) is acceptable for up to 3 months. Keep away from light and moisture.
• Reconstituted solution: Store in the refrigerator at 2–8°C; stable for approximately 28–30 days. Keep the vial upright and away from light, and discard after 30 days regardless of remaining volume.
• Do not freeze reconstituted peptide. Freeze-thaw cycles cause aggregation and loss of activity. Once reconstituted, the vial must remain refrigerated throughout.
• Light protection: Melanotan II is light-sensitive. Store the vial in the dark and avoid extended exposure to direct lighting.
• Transport: Use an insulated cooler with an ice pack for any travel exceeding 1–2 hours. Commercial medication pouches maintain 2–8°C for 24–48 hours. Avoid temperatures above 25°C during transport.

Side Effects and Safety Profile

Compared with purely regenerative peptides, Melanotan II has a considerably more pronounced side effect profile because, as a pan-agonist, it engages several receptor systems at once. Many of the reported effects are direct consequences of the mechanism of action rather than signs of contamination or toxicity. Robust long-term human data is absent.

Commonly Reported Observations

• Nausea, particularly in the first few days or after a dose increase. It is usually transient and more common at higher doses. A slow loading phase markedly reduces this reaction.
• Spontaneous facial flushing and a transient drop in blood pressure shortly after administration.
• Reduced appetite as a direct consequence of MC4R agonism.
• In male users, the literature describes spontaneous erections, especially within the first hour after administration.
• Increased pigmentation of moles, freckles, and new pigment spots. This is the most closely watched safety-relevant observation.
• Mild injection-site irritation, which can be minimized by rotating sites.

Less Common or Theoretical Concerns

• Changes to skin lesions: Because Melanotan II directly stimulates melanocyte activity, research discusses whether existing moles may darken or new pigmented lesions may appear. A medical skin check is considered important in the research context.
• Priapism: In rare cases, prolonged and painful erections have been described in male users, which constitute a medical emergency.
• Contamination risk from unverified sources: Several documented incidents are linked to untested material of unknown purity, not to the molecule itself. Purity and identity are therefore of high importance.
• Circulatory effects: The transient drop in blood pressure may be relevant for individuals prone to hypotension.

Contraindications

• History of melanoma or other skin cancer, and a high number of atypical moles
• Pregnancy and breastfeeding (insufficient safety data)
• Known cardiovascular disease or pronounced hypotension
• Known hypersensitivity to any component of the preparation

Consultation with a qualified healthcare professional is strongly recommended, particularly because of the dermatological safety considerations.

Combinations and Stacks

Melanotan II and Melanotan I

Melanotan II is frequently compared in research with Melanotan I. Melanotan I (afamelanotide) is more selective for the MC1R and therefore produces very few central nervous effects such as nausea, appetite suppression, or spontaneous erections. It is regarded in research as the more tolerable but slower-acting melanocortin peptide. A genuine simultaneous combination of the two is uncommon because their pigmentation pathways overlap; what matters more is the deliberate choice between potency (MT-II) and selectivity (MT-I).

Melanotan II and PT-141

PT-141 (bremelanotide) is a direct derivative of Melanotan II in which the amino group has been removed. As a result, PT-141 focuses on the central MC3R/MC4R effects related to sexual arousal without producing meaningful pigmentation. Combining the two peptides is unusual in research, as they engage overlapping receptors and their inflammatory and circulatory effects could add up. The comparison is more conceptual in nature and illustrates how a non-specific pan-agonist was refined into a targeted analog.

Melanotan II as a Standalone

Because of its pan-agonist properties and broad range of effects, Melanotan II is almost always considered as a single compound rather than within stacks in research practice. Combining it with additional centrally or vascularly active peptides increases complexity and makes it harder to attribute effects. Research-grade Melanotan II is available directly from BergdorfBio: Melanotan II at BergdorfBio.

Frequently Asked Questions

How does Melanotan II differ from Melanotan I?

Melanotan I is more selective for the melanocortin-1 receptor and therefore produces mostly pigmentation with only minor central nervous effects. Melanotan II is a pan-agonist that additionally activates MC3R and MC4R, so it acts more strongly, more quickly, and with more pronounced side effects such as nausea, appetite suppression, and sexual arousal. Melanotan I is regarded as more tolerable, Melanotan II as more potent.

Why don't IU match the milligram dose?

The IU scale on an insulin syringe is purely a volume scale: 1 IU equals 0.01 mL. The mass contained in that volume depends entirely on the concentration of the dissolved solution. At 5 mg/mL, 5 IU contains exactly 0.25 mg of peptide. The calculator translates your target dose in milligrams into the corresponding volume and the units to read off.

Does Melanotan II work without sun exposure?

Melanotan II stimulates melanocytes directly and can therefore, in principle, deepen pigmentation independently of UV. Research literature nonetheless describes that moderate UV exposure accelerates visible tanning because it triggers additional melanocyte activity. Excessive UV exposure is not advisable.

What do loading and maintenance phases mean?

In the loading phase, low doses, often daily, are used to reach a visible pigmentation level. Once that level is reached, research practice transitions to a maintenance phase, in which dosing occurs only 2–3 times per week to hold the state. The slow loading phase also reduces nausea and circulatory effects.

Why does Melanotan II cause nausea?

The nausea is a direct consequence of activating central melanocortin receptors, particularly the MC4R, and is not a sign of contamination. It is most common at the start and after dose increases and usually subsides as use continues. A low starting dose and a slow ramp are the most important measures.

Is Melanotan II an approved drug?

No. Melanotan II is not approved as a drug. It is traded strictly as a research-use compound. Various health authorities have warned against uncontrolled use, particularly because of the dermatological safety considerations and the risks posed by untested material.

How does Melanotan II affect moles?

Because Melanotan II directly increases melanin production, existing moles, freckles, and pigment spots may appear darker, and new pigment spots may become visible. This is the most frequently cited safety-relevant observation. Regular dermatological monitoring is considered important in the research context.

Where can I buy Melanotan II?

BergdorfBio offers research-grade Melanotan II with verified purity and concentration. View the product page: Buy Melanotan II at BergdorfBio. All products are sold strictly for research purposes.

Medical Disclaimer: The information on this page is provided for educational and research purposes only. Melanotan II is not an approved drug or medical treatment and is sold strictly for research use. Nothing on this page constitutes medical advice, diagnosis, or a recommendation to use any specific compound. Always consult a qualified healthcare professional before beginning any peptide protocol. BergdorfBio assumes no liability for the use or misuse of the information presented here.