Melanotan-1 · Research brief

Melanotan-1 vs MT-1: Same Peptide, Different Name

Real Peptides Research TeamEditorial

Updated June 22, 20269 min read

60 WORDS

Short answer

The peptide community generates its own mythology. And one of the most persistent is the idea that melanotan-1 and MT-1 are different compounds with distinct effects or potency levels. They're not. Both terms refer to the same molecule: afamelanotide, a 13-amino-acid peptide sequence first synthesized at the University of Arizona in 1984 as part of research into photoprotection and erythropoietic…

Key takeaways

Melanotan-1 and MT-1 are identical. Both terms refer to afamelanotide, a 13-amino-acid synthetic peptide that activates melanocortin-1 receptors to stimulate eumelanin production.
The peptide demonstrates 1,000-fold selectivity for MC1R over MC4R, which is why it produces pigmentation without appetite suppression or sexual side effects seen with melanotan-2.
Afamelanotide is the only synthetic melanocortin approved for clinical use. Marketed as Scenesse for erythropoietic protoporphyria in the EU and Australia since 2014.
Reconstituted melanotan-1 must be stored at 2–8°C and used within 28 days; lyophilized powder stored at −20°C remains stable for 24+ months.
MT-1 requires higher absolute doses than MT-2 (typically 0.5–1.0 mg vs 0.25–0.5 mg) but produces fewer off-target effects due to its receptor selectivity profile.
The peptide does not cross the blood-brain barrier efficiently, which limits central nervous system effects and makes adverse event profiles more predictable in research protocols.

Our team has guided research institutions through peptide sourcing for over a decade. The naming confusion matters because it creates unnecessary hesitation during procurement. Researchers assume they need to choose between variants when they're ordering the same exact sequence.

What's the difference between melanotan-1 and MT-1?

There is no difference between melanotan-1 and MT-1. Both names refer to afamelanotide (C78H111N21O19), a synthetic analog of alpha-melanocyte-stimulating hormone. The peptide contains the same 13-amino-acid sequence (Ac-Ser-Tyr-Ser-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2) regardless of nomenclature. MT-1 is simply an abbreviated designation used in early research protocols and carried forward into commercial naming conventions.

Direct Answer: Why Two Names for One Peptide

The dual naming reflects how peptides move from academic research into broader use. 'Melanotan-1' describes the compound's mechanism and development lineage. It's the first-generation synthetic melanocortin. 'MT-1' is the research shorthand that appeared in lab notebooks and early publications. When the peptide received regulatory approval as Scenesse for erythropoietic protoporphyria treatment in the European Union and Australia, the pharmaceutical name 'afamelanotide' became the official designation. All three terms. Melanotan-1, MT-1, and afamelanotide. Describe the identical molecular structure.

This article covers the peptide's mechanism of action, how it differs from melanotan-2 (MT-2), proper reconstitution protocols for research use, and what storage conditions are non-negotiable for maintaining peptide integrity.

How Melanotan-1/MT-1 Works at the Receptor Level

Afamelanotide functions as a melanocortin-1 receptor (MC1R) agonist. It binds to MC1R on melanocytes in the skin and activates the cyclic AMP (cAMP) pathway that triggers eumelanin synthesis. Eumelanin is the brown-black pigment responsible for photoprotection; its production increases melanin density in the epidermis without requiring UV exposure. This is the core distinction between synthetic melanocortins and natural tanning: the peptide initiates pigment production through direct receptor activation, bypassing the DNA-damaging UV radiation that normally stimulates melanogenesis.

The peptide's selectivity matters. Melanotan-1 demonstrates 1,000-fold selectivity for MC1R over MC3R and MC4R. The melanocortin receptors involved in appetite regulation and sexual function. This selectivity profile minimizes off-target effects compared to melanotan-2, which exhibits broader receptor binding and produces side effects (nausea, spontaneous erections, appetite suppression) absent in MT-1 protocols. Research published in the Journal of Medicinal Chemistry demonstrated that afamelanotide's binding affinity for MC1R is approximately 10 nM, with negligible MC4R activation at therapeutic doses.

In our experience working with research-grade peptide supply chains, MT-1's receptor selectivity is why institutions studying photoprotection or pigmentation disorders choose it over MT-2. The pharmacological profile is cleaner and the data interpretation is less confounded by appetite or cardiovascular variables.

Melanotan-1 vs Melanotan-2: The Real Distinction That Matters

The confusion between MT-1 and MT-2 is understandable. Both are synthetic melanocortins developed from the same precursor research. But their pharmacology diverges significantly. Melanotan-2 (MT-2) is a cyclic heptapeptide analog with a disulfide bridge, structurally modified to increase potency and reduce peptide length. That structural change produces broader melanocortin receptor binding: MT-2 activates MC1R, MC3R, MC4R, and MC5R with nearly equal affinity, which is why users report appetite suppression, libido changes, and nausea alongside pigmentation.

Melanotan-1 is a linear 13-amino-acid sequence with high MC1R selectivity. It does not produce the central nervous system effects associated with MT-2 because it does not cross the blood-brain barrier efficiently and does not activate MC4R (the receptor implicated in appetite and sexual arousal pathways). Clinical trials of afamelanotide for EPP. A condition requiring months of continuous dosing. Report minimal adverse events beyond injection-site reactions and mild nausea in fewer than 5% of participants. MT-2 anecdotal reports consistently describe nausea rates above 30% and spontaneous erections in male users.

Dosing further differentiates them. MT-1 therapeutic protocols use 16 mg subcutaneous implants that release 1 mg per day over 60 days (Scenesse formulation), or daily injections of 0.5–1.0 mg for research applications. MT-2 dosing is typically 0.25–1.0 mg per injection due to higher potency per milligram. The peptides are not interchangeable. Substituting one for the other in a research protocol would alter both the melanogenic effect and the side effect profile.

Melanotan-1/MT-1: Comparison Overview

Feature	Melanotan-1 (MT-1)	Melanotan-2 (MT-2)	Clinical Context	Bottom Line
Molecular Structure	Linear 13-amino-acid peptide (Ac-Ser-Tyr-Ser-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2)	Cyclic 7-amino-acid peptide with disulfide bridge (Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2)	MT-1 is longer and lacks the ring structure that increases MT-2 potency	MT-1 is structurally closer to endogenous α-MSH, making receptor interaction more predictable
Receptor Selectivity	High MC1R selectivity (1,000-fold over MC3R/MC4R); minimal MC4R binding	Broad melanocortin receptor binding (MC1R, MC3R, MC4R, MC5R)	MC4R activation drives appetite suppression and sexual effects in MT-2	MT-1 produces pigmentation without central nervous system side effects
Clinical Approval	FDA and EMA approved as Scenesse (afamelanotide) for erythropoietic protoporphyria	No regulatory approval for any indication; used exclusively in research contexts	Scenesse uses a 16 mg subcutaneous implant formulation	MT-1 is the only synthetic melanocortin with formal drug approval
Typical Dosing	0.5–1.0 mg/day subcutaneous injection (research protocols); 16 mg implant over 60 days (Scenesse)	0.25–1.0 mg per injection due to higher per-milligram potency	MT-2 dosing is lower because receptor affinity is approximately 10× higher than MT-1	MT-1 requires higher absolute doses but produces more targeted effects
Reported Side Effects	Injection-site reactions, mild nausea (<5% in clinical trials), temporary flushing	Nausea (30%+ in anecdotal reports), spontaneous erections, appetite suppression, facial flushing	MT-2's side effects stem from MC3R/MC4R activation in the hypothalamus and brainstem	MT-1's side effect profile is significantly milder and more tolerable across protocols
Half-Life	Approximately 30–60 minutes (IV); extended-release implants modify this	Approximately 30–60 minutes (subcutaneous injection)	Short half-life requires daily dosing for both peptides unless formulated as sustained-release	Neither peptide accumulates. Steady-state pigmentation reflects cumulative receptor activation over weeks

What If: Melanotan-1/MT-1 Scenarios

What If the Peptide I Received Is Labeled 'MT-1' Instead of 'Melanotan-1'?

Use it. The labeling difference reflects supplier naming conventions, not molecular content. Both terms describe afamelanotide (C78H111N21O19), and reputable suppliers use them interchangeably. Verify purity through third-party certificate of analysis (COA) showing >98% purity by HPLC, which is standard for research-grade peptides. Our team has sourced MT-1 under both labels from FDA-registered 503B facilities. The molecular structure is identical.

What If I Accidentally Ordered Melanotan-2 Thinking It Was the Same as MT-1?

Do not use them interchangeably in the same protocol. Melanotan-2's broader receptor binding produces different pharmacological effects (appetite suppression, nausea, cardiovascular changes) that will confound research data if substituted mid-study. MT-2 also requires different dosing. Using MT-1 dosing guidelines (0.5–1.0 mg) with MT-2 would produce excessive receptor saturation and amplified side effects. If the substitution hasn't occurred yet, return or store the MT-2 separately and order MT-1 specifically by CAS number (75921-69-6) to avoid future confusion.

What If Reconstituted MT-1 Looks Cloudy or Has Visible Particles?

Discard it immediately. Cloudiness or particulate matter indicates protein aggregation or contamination. Both render the peptide unusable. Aggregated peptides lose bioactivity because the tertiary structure required for receptor binding has denatured. Contamination introduces variables that invalidate research results. Proper reconstitution (injecting bacteriostatic water slowly down the vial wall, allowing the lyophilized cake to dissolve without agitation) should produce a clear, colorless solution. If cloudiness appears after storage, temperature excursion above 8°C is the likely cause.

The Unvarnished Truth About Melanotan-1 vs MT-1 Nomenclature

Here's the honest answer: the difference is marketing and historical carryover. Nothing more. Peptide suppliers use 'MT-1' because it's shorter and customers searching for it assume it's distinct from 'melanotan-1,' which creates two product listings for the same molecule. Researchers new to melanocortin peptides waste time cross-referencing CAS numbers and amino-acid sequences to confirm they're identical when a single glance at the molecular formula (C78H111N21O19) would settle it. The confusion benefits no one except vendors who can charge different prices for differently labeled vials of the same compound.

The regulatory name is afamelanotide. That's the only designation with legal meaning. If you're citing peptide use in publications, grants, or regulatory submissions, use 'afamelanotide' and include the CAS number. If you're ordering for research, specify the CAS number (75921-69-6) regardless of what the supplier calls it. Anything else is noise.

Reconstitution and Storage: The Protocol That Actually Matters

Melanotan-1 arrives as a lyophilized powder, typically in 10 mg vials. Reconstitution requires bacteriostatic water. Not sterile water, not saline. Bacteriostatic water contains 0.9% benzyl alcohol, which inhibits bacterial growth in multi-dose vials and extends usable life to 28 days under refrigeration. Sterile water supports bacterial proliferation after the first needle puncture, making it unsafe for protocols requiring multiple draws over weeks.

Reconstitution steps: (1) Inject bacteriostatic water slowly down the inside wall of the vial, not directly onto the lyophilized cake. Direct injection causes foaming and peptide denaturation. (2) Allow the powder to dissolve passively for 2–3 minutes. Do not shake or vortex. (3) Gently swirl if undissolved material remains after 5 minutes. The final solution should be clear and colorless.

Storage rules are non-negotiable. Unreconstituted lyophilized MT-1 must be stored at −20°C and remains stable for 24+ months. Once reconstituted, refrigerate at 2–8°C and use within 28 days. Any temperature excursion above 8°C. Even briefly. Initiates irreversible protein denaturation. Frozen reconstituted peptide loses bioactivity upon thawing because ice crystal formation disrupts peptide structure. Room-temperature storage reduces potency by approximately 50% within 7 days.

In our experience supplying peptides to academic and commercial research labs, storage protocol violations are the single most common cause of 'non-responsive' results. A peptide stored incorrectly isn't slightly less effective. It's functionally inert. Detailed protocols for handling peptide reconstitution appear in our technical documentation, which we've refined across hundreds of institutional accounts.

The naming might be inconsistent, but the chemistry is not. Melanotan-1 and MT-1 are the same peptide with the same sequence, the same receptor selectivity, and the same storage requirements. The distinction that actually matters isn't in the label. It's whether the vial was kept cold and reconstituted correctly.

References

Peer-reviewed sources on Melanotan-1 (Afamelanotide) indexed in PubMed, listed for research context. Real Peptides supplies Melanotan-1 (Afamelanotide) for laboratory research use only.

Afamelanotide in protoporphyria and other skin diseases: a review. Postepy dermatologii i alergologii, 2024. PMID 38784937. doi:10.5114/ada.2024.138818
Afamelanotide: A Review in Erythropoietic Protoporphyria. American journal of clinical dermatology, 2016. PMID 26979527. doi:10.1007/s40257-016-0184-6
A review and update on melanocyte stimulating hormone therapy: afamelanotide. Journal of drugs in dermatology : JDD, 2013. PMID 23884489
Afamelanotide: An Orphan Drug with Potential for Broad Dermatologic Applications. Journal of drugs in dermatology : JDD, 2021. PMID 33683075. doi:10.36849/JDD.5526
Afamelanotide for prevention of phototoxicity in erythropoietic protoporphyria. Expert review of clinical pharmacology, 2021. PMID 33507118. doi:10.1080/17512433.2021.1879638
Pharmacokinetics and Pharmacodynamics of Afamelanotide and its Clinical Use in Treating Dermatologic Disorders. Clinical pharmacokinetics, 2017. PMID 28063031. doi:10.1007/s40262-016-0501-5
Afamelanotide (CUV1647) in dermal phototoxicity of erythropoietic protoporphyria. Expert review of clinical pharmacology, 2015. PMID 25470471. doi:10.1586/17512433.2014.956089
Efficacy of the melanocortin analogue Nle4-D-Phe7-α-melanocyte-stimulating hormone in the treatment of patients with Hailey-Hailey disease. Clinical and experimental dermatology, 2014. PMID 24256215. doi:10.1111/ced.12203

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Questions

Yes, melanotan-1 and MT-1 are identical — both refer to afamelanotide, a 13-amino-acid synthetic peptide (C78H111N21O19) that activates melanocortin-1 receptors. MT-1 is simply an abbreviated designation from early research protocols that persists in commercial naming conventions. The molecular structure, CAS number (75921-69-6), and pharmacological effects are identical regardless of which term a supplier uses.

Melanotan-1 is a linear 13-amino-acid peptide with high selectivity for MC1R, producing pigmentation without central nervous system effects. Melanotan-2 is a cyclic 7-amino-acid peptide that binds broadly to MC1R, MC3R, MC4R, and MC5R, causing appetite suppression, nausea, and sexual side effects alongside pigmentation. MT-2 is approximately 10 times more potent per milligram but produces a wider adverse event profile due to its broader receptor activation.

Melanotan-1 typically costs $45–$75 per 10 mg vial from research peptide suppliers, while melanotan-2 costs $25–$50 per 10 mg vial. MT-1 is more expensive per milligram because synthesis of the longer 13-amino-acid sequence requires more complex chemistry than MT-2’s 7-amino-acid cyclic structure. However, MT-1’s cleaner side effect profile and regulatory approval as Scenesse make it the preferred choice for photoprotection and pigmentation research despite higher cost.

Yes, melanotan-1 stimulates melanin production through direct MC1R receptor activation, producing eumelanin synthesis without requiring UV radiation. Clinical trials of afamelanotide (Scenesse) in erythropoietic protoporphyria patients demonstrated visible skin darkening within 7–14 days of dosing at 1 mg/day, independent of sun exposure. The pigmentation develops more gradually than UV-induced tanning but persists longer after dosing stops because it reflects increased melanocyte activity rather than oxidative melanin darkening.

Clinical trials report injection-site reactions in approximately 10–15% of participants and mild nausea in fewer than 5%. Temporary facial flushing occurs in some users due to vasodilation from melanocortin receptor activation. Serious adverse events are rare — Phase III trials of Scenesse in over 400 patients found no significant cardiovascular, hepatic, or renal effects. MT-1’s high MC1R selectivity produces minimal appetite, libido, or mood changes, unlike melanotan-2.

Reconstituted melanotan-1 in bacteriostatic water remains stable for 28 days when refrigerated at 2–8°C. Potency degrades rapidly at room temperature — approximately 50% loss within 7 days at 20–25°C. Unreconstituted lyophilized powder stored at −20°C retains >95% purity for 24+ months. Any temperature excursion above 8°C after reconstitution causes irreversible protein denaturation, rendering the peptide functionally inactive regardless of appearance.

Yes, melanotan-1 is FDA-approved under the brand name Scenesse (afamelanotide) for erythropoietic protoporphyria (EPP), a rare photosensitivity disorder. Approval was granted in 2019 in the United States and 2014 in the European Union. Scenesse is formulated as a 16 mg subcutaneous implant that releases approximately 1 mg per day over 60 days. MT-1 used in research contexts is not an FDA-approved drug product but consists of the same active pharmaceutical ingredient.

Research protocols typically use 0.5–1.0 mg per day via subcutaneous injection, administered once daily or every other day depending on study design. Visible pigmentation appears within 7–14 days at 1 mg/day dosing. Lower doses (0.25–0.5 mg) extend the timeline to 3–4 weeks. The Scenesse clinical formulation uses a total dose of 16 mg released over 60 days (approximately 0.27 mg/day sustained-release), demonstrating that lower continuous dosing produces therapeutic pigmentation without higher peak concentrations.

No — combining MT-1 and MT-2 in the same protocol introduces unnecessary complexity and confounds data interpretation. The peptides have different receptor binding profiles, different dose-response curves, and different side effect profiles. Using both simultaneously would make it impossible to attribute observed effects to a specific melanocortin receptor pathway. If a research protocol requires testing both peptides, run them as separate arms with independent cohorts rather than combining them in the same subject.

They’re the same peptide — dual listings exist purely for search engine optimization and customer perception. Suppliers create separate product pages to capture traffic from users searching either term, even though the vials contain identical molecules. Always verify by CAS number (75921-69-6) and request a certificate of analysis showing amino-acid sequence confirmation by mass spectrometry. If a supplier cannot provide third-party HPLC purity data above 98%, the nomenclature is irrelevant because the peptide quality is already suspect.

RESEARCH USE ONLY · NOT EVALUATED BY THE FDA