Melanocortin-related names can be easy to confuse. Melanotan I is a historical name mapped to afamelanotide. Melanotan II and bremelanotide are related cyclic peptides, but they are not the same substance. KPV is a three-residue alpha-MSH-associated sequence with a different evidence base.[3,10–12]
This hub keeps those identities separate. It explains receptor, cell, animal, ex-vivo, and human research without turning family resemblance into an equivalence claim.
This page is educational. It does not provide medical advice, treatment recommendations, dosing, preparation, administration, reconstitution, or directions for human or veterinary use. It does not authenticate a Serum Research catalog material or establish its quality, safety, or equivalence to a studied intervention.
Why melanocortin names require extra care
A peptide family may include a parent hormone, fragments, cyclic and linear analogues, salts, and named finished products. Similar sequence motifs or receptor activity can explain why substances are studied together. They do not establish identical pharmacology, formulation, safety, clinical effect, or regulatory status.
FDA substance identifiers distinguish named structures and synonyms, but a UNII is not approval or proof of catalog identity.[10–12] FDA evaluates named drug applications, not every material sharing an ingredient nickname.[8] The approved-drug versus research-material guide explains that product boundary.
For example, FDA records describe Melanotan II with a terminal carboxamide, while bremelanotide has a terminal carboxylic acid.[11,12] That structural difference is not just a branding distinction. The sequence and modifications guide explains why terminal chemistry, stereochemistry, and cyclization must be specified.
Melanotan I and afamelanotide
FDA’s afamelanotide substance record includes Melanotan I and the development name CUV1647.[10] That identity mapping does not establish what a separately supplied material contains.
An early human study reported pharmacokinetic and pigmentation measurements in three male volunteers using a particular Melanotan-I preparation.[4] Such a small, short study cannot establish uncommon risks, long-term safety, or equivalence to a later finished product.
The SCENESSE label describes an afamelanotide-acetate implant with a specific formulation. Its labeled purpose is to increase pain-free light exposure in adults with a history of phototoxic reactions from erythropoietic protoporphyria (EPP), not general cosmetic tanning.[1] At this check, the latest label listed in the FDA application history was supplement 7, revised August 2024.[15]
The label includes serious hypersensitivity and pigmentary-lesion monitoring warnings.[1] It does not approve a vial called Melanotan I or establish that the vial matches the finished implant. The active-ingredient and formulation guide explains why an ingredient name cannot stand in for the whole product.
Melanotan II
Melanotan II has its own FDA substance record.[11] A pilot phase 1 report involved three men and described pigmentation measurements alongside adverse effects including nausea, somnolence, and fatigue.[5] A later double-blind, placebo-controlled crossover study involved ten men with psychogenic erectile dysfunction and assessed short-term physiological outcomes.[9]
These are limited early human studies, not a general safety assessment or a demonstration of long-term clinical benefit. Small samples cannot reliably characterize uncommon harms, and a short physiological measurement does not settle patient-important outcomes across populations. The study-reading guide explains why design, population, outcome, and follow-up all matter.
Melanotan II is neither afamelanotide nor bremelanotide. It must not inherit the SCENESSE or Vyleesi labels, and these historical studies do not validate a catalog lot.
Bremelanotide / PT-141
FDA’s substance record maps PT-141 free base to bremelanotide.[12] Vyleesi is a named FDA-approved product containing bremelanotide acetate.[2,16] Development-name overlap is not finished-product equivalence.
The two RECONNECT trials randomized 1,267 women with acquired, generalized hypoactive sexual desire disorder (HSDD). The paper reports 1,247 participants in the safety population and 1,202 in its modified intent-to-treat efficacy population. Both trials met their co-primary desire and related-distress endpoints. The key secondary change in the number of satisfying sexual events associated with study-drug use did not differ significantly from placebo; the remaining ranked secondary outcomes consequently became supportive or exploratory.[6]
The paper used last observation carried forward for its primary analysis and reported more withdrawals in the bremelanotide groups. Nausea, flushing, and headache were more frequent than with placebo.[6] These limits belong beside the endpoint findings; a null secondary result should not disappear behind positive co-primary results or a post-hoc percentage analysis.
Palatin sponsored and participated in study design, execution, analysis, and reporting; AMAG supported manuscript editorial assistance. The paper discloses author financial relationships.[6] Those roles are relevant context, not a substitute for examining the methods.
Both trial registries currently report completed studies and posted results. Their last posted updates are April 9, 2021 for study 301 and January 28, 2021 for study 302.[13,14] Neither registry supplied a protocol or statistical-analysis-plan document in the checked record. This hub does not claim independent verification of those complete documents.
The DailyMed Vyleesi record was updated November 13, 2025; its prescribing text is revised March 2024.[2] The indication is limited to premenopausal women with acquired, generalized HSDD not attributable to the specified medical, psychiatric, relationship, or substance causes. It is not an indication for men, postmenopausal women, or sexual-performance enhancement. The label includes cardiovascular contraindications and warnings concerning blood pressure, nausea, and focal hyperpigmentation.[2] No use instructions are reproduced here.
KPV
KPV stands for lysine-proline-valine, a three-residue sequence associated with the end of alpha-melanocyte-stimulating hormone. A fragment's sequence shorthand does not establish the parent hormone's identity, terminal chemistry, or receptor pharmacology.[3]
A primary paper investigated KPV in cultured human-derived intestinal and immune cells and in mouse colitis models.[7] Human-derived cell lines are not participants in a clinical trial. FDA’s KPV briefing also describes a study using excised human cadaver skin; that is an ex-vivo model, not clinical exposure evidence.[3] The evidence-model guide distinguishes these settings.
The FDA briefing was dated May 12, 2026 and prepared for the July 23–24 advisory meeting. It distinguishes KPV free base from KPV acetate and reports that FDA did not identify clinical, human pharmacology, case-report, or other human-exposure evidence for the reviewed materials. Its adverse-event searches had their own earlier cutoff dates. Absence of identified reports is not evidence of safety.[3]
FDA staff proposed against adding the reviewed forms to the section 503A bulks list; the briefing itself is not a final determination.[3] Its evidence gaps must not be reframed as proven human inflammation, skin, gut, or healing benefits. KPV is not equivalent to alpha-MSH, afamelanotide, Melanotan II, or bremelanotide.
Compare the research questions
| Topic | Central question | Boundary that must remain visible |
|---|---|---|
| Melanotan I / afamelanotide | How do a historical name, defined substance, early research, and finished product relate? | SCENESSE's formulation and EPP indication are product-specific |
| Melanotan II | What do very small, short human studies establish? | A distinct cyclic peptide with unresolved broader safety and outcome questions |
| Bremelanotide / PT-141 | Which controlled-trial endpoints were positive or null, and how were data analyzed? | Vyleesi evidence does not validate a catalog vial |
| KPV | What do cell, excised-tissue, and animal findings show? | A dated review's human-evidence gap is not proof of safety or clinical benefit |
A status check must use the exact substance, trial, application, and source date. An approved drug, a completed trial, a substance identifier, and an advisory briefing are different kinds of records.
Scope and access limits
This is an identity-led overview, not a systematic review, treatment comparison, or comprehensive safety assessment. The cited early Melanotan studies and KPV paper were checked at the abstract level; their complete methods and underlying data were not independently verified. RECONNECT's accessible published methods, results, discussion, and disclosures were inspected, but its external appendix was not accessible and complete protocols and analysis plans were not obtained.
Regulatory labels, substance records, and the FDA KPV assessment supplement those sources; they do not remove the access limitations. No independent participant-level analysis, laboratory testing, catalog authentication, or clinical recommendation is claimed.
Published compound records
Frequently asked questions
Are Melanotan I and afamelanotide the same?
FDA maps the historical name to afamelanotide at the substance level. A named finished afamelanotide product nevertheless remains distinct from another material labeled Melanotan I.
Is Melanotan II the same as bremelanotide?
No. They are distinct cyclic peptides, including different terminal chemistry, with separate identity and evidence records.
Does Vyleesi approval make PT-141 catalog material FDA approved?
No. Approval belongs to the named finished product and its application, formulation, manufacturing controls, population, and label.
Has KPV been tested in people?
The cited FDA assessment reported no identified human clinical or exposure data for the reviewed KPV forms at that evaluation. That is a dated evidence-search finding, not a claim that no exposure could ever have occurred. Excised human skin and human-derived cell lines are not clinical studies.
Does receptor binding prove a clinical effect?
No. It addresses molecular recognition or signaling in a defined system. Direct human evidence is needed to assess clinical outcomes.
Does this hub provide tanning, sexual-performance, inflammation, or other use guidance?
No. It explains identity and evidence boundaries without use instructions or outcome recommendations.
Primary and official sources
- FDA, SCENESSE prescribing information, revised August 2024
- DailyMed, Vyleesi label, updated November 13, 2025; prescribing text revised March 2024
- FDA, KPV briefing dated May 12, 2026, for the July 23–24 advisory meeting
- Ugwu et al., Melanotan-I early human study, PMID 9113347
- Dorr et al., Melanotan II pilot phase 1 study, PMID 8637402
- Kingsberg et al., RECONNECT phase 3 trials, PMID 31599840; open published paper, PMCID PMC6819021
- Dalmasso et al., KPV cell and animal study, PMID 18061177
- FDA, Approved Drugs: Questions and Answers
- Wessells et al., Melanotan II placebo-controlled crossover study, PMID 9679884
- FDA GSRS, afamelanotide, UNII QW68W3J66U
- FDA GSRS, Melanotan II, UNII UPF5CJ93X7
- FDA GSRS, bremelanotide, UNII 6Y24O4F92S
- ClinicalTrials.gov, RECONNECT study 301, NCT02333071
- ClinicalTrials.gov, RECONNECT study 302, NCT02338960
- Drugs@FDA, SCENESSE application 210797 history
- Drugs@FDA, Vyleesi application 210557 history
Review and corrections
Sources checked September 2, 2026 (America/Edmonton), corresponding to September 3, 2026 (UTC). Regulatory and trial records may change after this check.
Serum Research is responsible for this page's editorial content and corrections. No independent scientific, clinical, statistical, analytical, or regulatory review is claimed. This is nonmedical educational material, not a catalog-quality or equivalence assessment. Read how we review evidence, browse the research library, or send a correction.