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MT2 Reconstitution Calculator & Guide
Melanotan II / Melanocortin Receptor Agonist
Melanotan II, often shortened to MT2, is an unapproved synthetic melanocortin peptide developed to stimulate skin pigmentation. Early human research showed that it can increase tanning and can also affect sexual function, but modern tanning products sold online are unapproved and may have important safety and product-quality risks. This page explains the human evidence, regulatory status, reported adverse effects, skin and mole concerns, and educational reconstitution math.
Evidence Snapshot
MT2 research at a glance
Standardized regulatory and evidence context so research compounds, investigational drugs, and approved medications are not treated as if they have the same level of human evidence.
Regulatory status
Not FDA-approvedDevelopment / evidence stage
Phase 1 (historical)
Historical clinical development
Human evidence level
Human pharmacology / early clinicalPrimary mechanism
Nonselective melanocortin receptor agonist associated with pigmentation and sexual-function effects.
WADA context
Non-approved substance — S0 may applyHuman intervention evidence
Early human studies exist, but clinical development did not produce an FDA-approved tanning or cosmetic-pigmentation drug.
Human biology evidence
Small human studies demonstrated pigmentation-related and erectile/sexual effects, confirming meaningful melanocortin activity in humans.
Key takeaway
Melanotan II has more direct human pharmacology than many research peptides, but it remains unapproved and lacks a validated consumer-use safety framework.
Evidence labels describe the research base and regulatory context; they are not treatment, dosing, or use recommendations. Review dates describe the last BACToBasics source check for this evidence summary. Anti-doping rules can change and should be verified with the applicable authority.
MT2 Reconstitution Calculator
Enter the vial amount, liquid volume, and amount you want to calculate. BACToBasics will automatically calculate concentration, liquid volume, and U-100 syringe-unit equivalents.
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Calculator values are educational math inputs only. They are not recommended preparation amounts, doses, or use protocols.
MT2 Reconstitution Math
Reconstitution math starts with the amount contained in the vial and the liquid volume used in the calculation. Dividing the vial amount by the liquid volume gives the resulting concentration.
Example vial amount
10 mg
| Liquid Volume | Calculation | Concentration |
|---|---|---|
| 1 mL | 10 mg ÷ 1 mL | 10 mg/mL |
| 2 mL | 10 mg ÷ 2 mL | 5 mg/mL |
| 3 mL | 10 mg ÷ 3 mL | 3.3333 mg/mL |
This table demonstrates concentration math only. The liquid volumes shown are examples for comparison and are not preparation recommendations.
More Reconstitution Tools
Need to compare different liquid volumes or convert between mg, mcg, mL, and U-100 units? Use the dedicated BACToBasics calculator tools.
What is Melanotan II?
Melanotan II is a synthetic cyclic analogue of alpha-melanocyte-stimulating hormone, or alpha-MSH. It activates multiple melanocortin receptors rather than acting selectively at a single receptor. The compound was originally investigated for its ability to increase pigmentation, but it is not an FDA-approved tanning medication.
How does MT2 increase pigmentation?
Melanocortin signaling in skin can stimulate melanocytes and increase production of melanin, particularly eumelanin. This is why Melanotan II can darken overall skin pigmentation and may also darken freckles, moles, and other melanocytic lesions. Pigmentation effects do not remove the DNA-damaging and skin-cancer risks associated with ultraviolet exposure.
What did early human studies show?
A small Phase 1 pilot study in three healthy male volunteers found that Melanotan II increased skin pigmentation. The study also reported nausea, fatigue or somnolence at higher studied exposures, and spontaneous erections lasting for extended periods in some participants. The study demonstrated biological activity but was far too small to establish a modern safety profile.
Why does Melanotan II affect sexual function?
Melanotan II activates melanocortin receptors involved not only in pigmentation but also in central nervous-system pathways related to sexual arousal. Spontaneous erections were observed in early clinical research, and this melanocortin biology eventually contributed to development of other, distinct melanocortin drugs. Melanotan II itself is not an approved treatment for erectile or sexual dysfunction.
Is Melanotan II FDA-approved?
No. Melanotan II is not FDA-approved for tanning or cosmetic pigmentation. In 2026, FDA's compounding materials noted that prior nominations involving Melanotan II had been withdrawn while FDA planned further Pharmacy Compounding Advisory Committee review. FDA also identifies potential safety concerns for compounded Melanotan II, including immunogenicity risks related to aggregation or peptide impurities.
Online MT2 products and dose-label accuracy
Unapproved online tanning products may not reliably contain what their labels claim. In August 2026, Australia's Therapeutic Goods Administration reported laboratory testing of five Melanotan II nasal-spray bottles labeled as 30mg. The estimated amount ranged from 22mg to 54mg per bottle. That finding illustrates why an online label should not be assumed to verify identity, strength, purity, or consistency.
MT2 and freckles or moles
Darkening of existing freckles and melanocytic nevi has been repeatedly reported with Melanotan exposure. Case reports have also described development or rapid change of atypical melanocytic lesions after use. These observations are clinically important, but case reports cannot by themselves prove that Melanotan II caused a particular lesion or cancer.
Does Melanotan II cause melanoma?
A causal relationship has not been established. Published case reports have described melanoma occurring after Melanotan II exposure, sometimes alongside tanning-bed use, and regulators have highlighted concern about changing moles and potential skin-cancer risk. These reports are signals for caution rather than proof that Melanotan II directly causes melanoma. Ultraviolet exposure itself is a well-established skin-cancer risk.
Commonly reported Melanotan II adverse effects
Human studies and regulatory warnings describe effects including nausea, headache, facial flushing, reduced appetite, fatigue, yawning or stretching, and spontaneous erections. Because contemporary online products are unapproved and may vary in composition, adverse effects reported from real-world use cannot always be attributed to a known amount of pure Melanotan II.
Rare but serious adverse-event reports
Published case reports have described serious events after Melanotan II exposure, including ischemic priapism, rhabdomyolysis with kidney dysfunction, and renal infarction. Case reports do not establish the frequency of these events, but they show that the safety concerns extend beyond cosmetic effects such as nausea or flushing.
Melanotan II and priapism
Because Melanotan II can trigger erections through melanocortin pathways, prolonged erections are a recognized concern. Multiple published case reports describe acute ischemic priapism after Melanotan exposure, including cases requiring invasive treatment. Priapism is a medical emergency because prolonged loss of normal penile blood flow can permanently damage erectile tissue.
MT2 vs Melanotan I and approved melanocortin drugs
Melanotan II should not be treated as interchangeable with Melanotan I, afamelanotide, or bremelanotide. These molecules differ in structure, receptor activity, regulatory status, formulation, and approved use. The existence of an approved melanocortin-related drug does not make unapproved Melanotan II tanning products equivalent in safety, quality, or effectiveness.
MT2 and UV exposure
Melanotan II is often marketed in connection with sun or tanning-bed exposure, but a darker tan does not make ultraviolet radiation harmless. UV radiation can cause DNA damage, premature skin aging, and skin cancer. BACToBasics does not recommend a UV-exposure or tanning protocol.
Research Melanotan II vs an approved medication
Products marketed online as research or cosmetic Melanotan II do not have the same assurance of identity, purity, concentration, sterility, manufacturing controls, labeling, and post-market surveillance as an FDA-approved pharmaceutical product. Recent regulator testing has demonstrated substantial variability in the labeled strength of real-world tanning products.
Melanotan II reconstitution math
Reconstitution calculations depend on the labeled amount in a vial and the liquid volume used. As a mathematical example, a 10mg vial combined with 2mL of liquid produces a concentration of 5mg per mL. BACToBasics uses examples like this only to demonstrate concentration, liquid-volume, and U-100 syringe-unit calculations rather than to recommend a Melanotan II preparation or dosing protocol.
Explore more about MT2
9 linksComparisons, research records, development tracking, blends, and related guides are available here when you want to go deeper.
Explore more about MT2
9 linksComparisons, research records, development tracking, blends, and related guides are available here when you want to go deeper.
Compare MT2
Direct comparison pages are selected from the indexable BACToBasics comparison catalog and update automatically as that catalog grows.
Research, updates & development
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MT2 research & development updates
Open the public timeline of sourced research records and material development changes tracked by BACToBasics.
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ResearchMT2 research sources
Open 2 curated research records for MT2.
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DevelopmentMT2 clinical development
Phase 1 (historical) · Historical clinical development. Pilot Phase 1 human study demonstrated tanning activity and dose-limiting adverse effects.
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Related peptide guides
Related guides are ranked from shared comparison pages, shared blend pages, and peptide category rather than a hand-maintained link list.
Relevant glossary concepts
Definitions are matched against the guide's structured title, subtitle, description, and educational sections.
FDA-Approved
A status indicating that the FDA has approved a specific drug product for one or more labeled uses after reviewing the required evidence and manufacturing information.
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GlossaryMilliliter (mL)
A metric unit of liquid volume equal to one-thousandth of a liter.
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GlossaryAgonist
A molecule that binds to a receptor and activates signaling through that receptor.
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MT2 FAQ
Tap a question to expand only the answer you want to read.
Is Melanotan II FDA-approved?
No. Melanotan II is not FDA-approved for tanning or cosmetic pigmentation.
Does Melanotan II actually make skin darker?
Yes, Melanotan II has demonstrated melanotropic activity in humans and can increase skin pigmentation. The existence of that biological effect does not establish that unapproved consumer products are safe.
Can Melanotan II darken freckles and moles?
Yes. Darkening and changes in melanocytic lesions have been reported. New, changing, irregular, bleeding, or otherwise concerning lesions should be evaluated by a qualified clinician.
Does Melanotan II cause melanoma?
A direct causal relationship has not been established. There are published melanoma case reports after Melanotan II exposure, but case reports cannot prove causation. UV exposure is independently a well-established melanoma and skin-cancer risk.
Can Melanotan II cause nausea?
Yes. Nausea was reported in early human clinical research and is also included in regulator safety warnings.
Why can Melanotan II cause erections?
Melanotan II activates melanocortin pathways involved in sexual arousal as well as pigmentation. Spontaneous erections occurred in early human studies.
Can Melanotan II cause priapism?
Rare published cases of acute ischemic priapism have been reported after Melanotan exposure. Priapism is a medical emergency.
Are online Melanotan II products accurately dosed?
They should not be assumed to be. In 2026, Australian regulator testing found large differences between the labeled and measured amounts across seized Melanotan II nasal-spray products.
Is Melanotan II the same as afamelanotide?
No. They are different melanocortin-related compounds with different structures, receptor profiles, formulations, and regulatory status.
Is Melanotan II the same as bremelanotide?
No. Bremelanotide is a distinct melanocortin drug with an FDA-approved indication, while Melanotan II is not FDA-approved for tanning or sexual dysfunction.
Does a Melanotan II tan protect against UV damage?
A darker appearance should not be treated as protection from ultraviolet radiation. UV exposure still causes DNA damage and increases skin-cancer risk.
How do you calculate Melanotan II concentration?
Divide the labeled amount in the vial by the liquid volume. For example, 10mg divided by 2mL equals 5mg per mL. This is concentration math, not a dosing recommendation.
Can the BACToBasics calculator handle MT2 math?
Yes. The calculator can convert a labeled vial amount and liquid volume into concentration, liquid volume, and U-100 syringe-unit equivalents for educational math purposes.
Sources & References
7 sourcesOpen the references when you want to inspect the research and regulatory sources behind this guide.
Sources & References
7 sourcesOpen the references when you want to inspect the research and regulatory sources behind this guide.
FDA safety page describing potential immunogenicity concerns involving compounded Melanotan II, including aggregation and peptide-related impurities.
FDA compounding-status document noting withdrawal of Melanotan II nominations and planned future PCAC review.
Regulator testing found large differences between labeled and measured Melanotan II amounts in seized nasal-spray products.
Small early human study demonstrating increased pigmentation and reporting nausea, fatigue, and spontaneous erections. PMID: 8637402.
Case report with analytically confirmed Melanotan II describing systemic toxicity, rhabdomyolysis, and renal dysfunction. PMID: 23121206.
Case report describing melanoma after Melanotan II exposure and tanning-bed use; the report is an association and does not establish causation. PMID: 24355990.
Case report of acute ischemic priapism after subcutaneous Melanotan II exposure. PMID: 33460908.
BACToBasics provides educational information and math tools only. This content is not medical advice, dosing advice, injection instruction, or a recommendation to use any peptide or medication.