This article is intended strictly for educational and scientific reference. Melanotan 1 and Melanotan 2 are not licensed medicines in the United Kingdom. They are not approved for human use by the MHRA. This content summarises published clinical and preclinical research only and does not constitute medical advice, dosing guidance, or encouragement to use these compounds. Always consult a qualified medical professional before considering any peptide-based research.
Overview
Melanotan 1 (MT-1, also known as afamelanotide) and Melanotan 2 (MT-2) are synthetic analogues of alpha-melanocyte-stimulating hormone (α-MSH), a naturally occurring neuropeptide. Both compounds have been the subject of published scientific research exploring their interactions with the melanocortin receptor system. This article summarises key findings from peer-reviewed studies and clinical trials for informational purposes.
Structural Differences
| Feature | Melanotan 1 (MT-1 / Afamelanotide) | Melanotan 2 (MT-2) |
|---|---|---|
| Structure | Linear peptide | Cyclic peptide |
| Receptor selectivity | Primarily MC1R | MC1R, MC3R, MC4R, MC5R |
| Regulatory status (UK) | Not MHRA-licensed for general use* | Not MHRA-licensed |
| Research status | Phase III trials completed (EPP indication) | Early-phase clinical studies only |
*Afamelanotide (Scenesse®) is EMA-approved in the EU for erythropoietic protoporphyria (EPP) but is not currently licensed in the UK for general use.
Melanotan 1 (Afamelanotide): Clinical Research Summary
MT-1 has the most extensive clinical research record of the two compounds. The majority of published human trials have investigated its use in the context of photodermatological conditions, particularly erythropoietic protoporphyria (EPP) — a rare genetic disorder causing extreme light sensitivity.
Key Published Studies
- Harms et al. (2009) — A Phase II randomised controlled trial published in The Lancet found that afamelanotide implants (16 mg subcutaneous implant) significantly increased pain-free sun exposure time in EPP patients compared to placebo, with a favourable tolerability profile.
- Langendonk et al. (2015) — A Phase III multicentre RCT published in the New England Journal of Medicine confirmed that afamelanotide 16 mg implants significantly improved quality of life and direct sun exposure in EPP patients. Adverse events were generally mild (nausea, fatigue, implant-site reactions).
- Biolcati et al. (2015) — A long-term observational study of EPP patients receiving afamelanotide over several years reported a consistent safety profile with no serious drug-related adverse events identified over extended use.
These trials used a controlled-release subcutaneous implant formulation (not injectable solution), administered under medical supervision in licensed clinical settings. The doses and delivery methods used in these trials are not replicable outside of a clinical environment.
Melanotan 2: Research Summary
MT-2 has a broader receptor binding profile than MT-1, interacting with MC1R, MC3R, MC4R, and MC5R. This broader activity has made it a subject of research across several areas, though human clinical data is considerably more limited than for MT-1.
Key Published Studies
- Wessells et al. (1998) — An early double-blind crossover study published in Urology investigated MT-2 in the context of male erectile function, noting physiological responses at doses used in the trial. The authors highlighted the need for further research and noted side effects including nausea and spontaneous yawning.
- Molinoff et al. (2003) — Research into bremelanotide (PT-141), a metabolite of MT-2, was published exploring its effects via MC4R pathways. This research ultimately led to the development of bremelanotide (Vyleesi®), which received FDA approval in 2019 for hypoactive sexual desire disorder — though this is a distinct compound from MT-2 itself.
- Van der Ploeg et al. (2002) — Preclinical and early human data on melanocortin receptor agonists highlighted the complexity of MC4R involvement in appetite regulation and metabolic function, areas that have since attracted significant pharmaceutical research interest.
It is important to note that MT-2 itself has not completed Phase III clinical trials for any indication and is not approved by any major regulatory body (MHRA, FDA, or EMA) for human therapeutic use.
Observed Effects in Clinical Literature
The following effects have been reported in peer-reviewed clinical research. This is a summary of what researchers have observed and documented — it is not a list of intended uses or benefits:
- Melanogenesis (skin pigmentation): Both MT-1 and MT-2 have demonstrated the ability to stimulate melanin production via MC1R in clinical studies, resulting in increased skin pigmentation.
- Photoprotection: MT-1 trials in EPP patients demonstrated a measurable increase in tolerance to light exposure, attributed to increased melanin density.
- Nausea: Consistently reported as a side effect in MT-2 studies, particularly at higher doses used in early trials.
- Spontaneous erections: Reported in MT-2 studies as an off-target effect of MC4R activation.
- Appetite suppression: Observed in some preclinical and early human studies, linked to MC4R activity.
Safety Considerations Highlighted in Research
Published research and regulatory guidance have raised several safety concerns that are important context for any scientific review of these compounds:
- The MHRA has issued public warnings about unlicensed melanotan products sold online, noting risks including unknown purity, sterility, and concentration of unregulated products.
- Case reports in dermatology literature have documented changes in existing naevi (moles) in individuals who self-administered melanotan compounds, raising concerns about melanocytic stimulation in at-risk individuals.
- MT-2's broad receptor activity (MC3R, MC4R, MC5R) means its physiological effects extend well beyond pigmentation, with implications for cardiovascular, metabolic, and neurological systems that are not fully characterised in human trials.
- No long-term human safety data exists for MT-2 outside of controlled clinical settings.
Regulatory Status in the United Kingdom
In the UK, both MT-1 and MT-2 fall under the regulatory oversight of the Medicines and Healthcare products Regulatory Agency (MHRA). Key points:
- Neither compound is licensed as a medicine for general use in the UK.
- The MHRA classifies melanotan products as unlicensed medicines when sold for human use, making their sale for this purpose illegal under the Human Medicines Regulations 2012.
- Afamelanotide (Scenesse®) holds EMA approval in the EU for EPP specifically, but this does not extend to UK market authorisation post-Brexit without separate MHRA approval.
- Products sold for research purposes must not be represented as suitable for human use.
Summary
MT-1 (afamelanotide) and MT-2 are structurally related melanocortin receptor agonists that have been studied in published clinical research. MT-1 has the stronger evidence base, with Phase III RCT data supporting its use in EPP under medical supervision. MT-2 has a broader receptor profile and a more limited human clinical dataset. Both compounds remain unlicensed for general human use in the UK.
This article is provided for scientific reference only. For reconstitution and handling reference information, see our Peptide Reconstitution Guide and Peptide Storage Guide.