Melanotan I vs Acetyl Tetrapeptide-5
Comprehensive side-by-side comparison of mechanisms, dosing, side effects, and research
Also: Afamelanotide, Scenesse
Melanotan I is the research name for afamelanotide (code CUV1647), a 13-amino-acid synthetic analog of alpha-melanocyte-stimulating hormone (alpha-MSH), also written as [Nle4, D-Phe7]-alpha-MSH or NDP-MSH. Sold as Scenesse, it was approved by the EMA in 2014 and the FDA in 2019 to increase pain-free light exposure in adults with erythropoietic protoporphyria (EPP), one of a few approved melanocortin drugs alongside bremelanotide (Vyleesi) and setmelanotide (Imcivree). The approval covers only the 16 mg bioresorbable implant placed under the skin by a clinician. The injectable 'Melanotan I' sold online is not approved for anything.
Also: Eyeseryl, Ac-beta-Ala-His-Ser-His
Acetyl tetrapeptide-5 is a short synthetic peptide sold by Lipotec (now Lubrizol) as Eyeseryl, made for eye creams that target under-eye puffiness. The pitch is that it reduces fluid leaking into the tissue under the eyes. It is a cosmetic ingredient, and nearly all of the human data comes from the company that sells it.
Key Comparison Insights
- Melanotan I is FDA approved, while Acetyl Tetrapeptide-5 remains in research stages.
- Both peptides belong to the Skin & Hair category, suggesting similar primary applications.
- Melanotan I has stronger research evidence (FDA Approved) compared to Acetyl Tetrapeptide-5 (Limited Research).
Detailed Comparison
| Attribute | Melanotan I | Acetyl Tetrapeptide-5 |
|---|---|---|
| Category | Skin & Hair | Skin & Hair |
| FDA Status | FDA Approved | Not FDA Approved |
| Clinical Status | Pre I II III IV FDA | Pre I II III IV FDA |
| Mechanism of Action | Afamelanotide binds and activates the melanocortin-1 receptor (MC1R) on pigment-producing melanocytes, driving production of eumelanin, the dark, photoprotective form of melanin. Two amino acid swaps from natural alpha-MSH - norleucine at position 4 and D-phenylalanine at position 7 - make it bind MC1R more tightly and resist breakdown, so it lasts far longer and acts more potently than the native hormone. The extra eumelanin absorbs and scatters light and also brings antioxidant and DNA-repair-supporting effects, which is why it raises the light dose EPP patients can tolerate before pain hits. Unlike Melanotan II, it is selective enough toward MC1R that it is not primarily a sexual-function or appetite agent. | The peptide is acetyl-beta-alanine-histidine-serine-histidine. The manufacturer's lab work claims three effects: it reduces vascular permeability (less fluid seeping out of small blood vessels, tested in an endothelial cell model), it inhibits glycation (sugar damage to proteins like collagen), and it has some ACE-inhibiting activity that is linked to fluid balance. All of that is in vitro and company-generated. An important reality check: under-eye bags have several causes, and a lot of them in older adults come from fat pads pushing forward and loose skin, not fluid. A peptide aimed at fluid cannot touch fat-pad bags, so even in the best case it fits morning puffiness better than structural eye bags. |
| Common Dosing | 500-1000 mcg daily (loading), then 500-1000 mcg 1-2x weekly (maintenance) Daily during loading (1-2 weeks), then 1-2x weekly maintenance | 1% of the Eyeseryl solution in an eye cream Twice daily |
| Administration | Subcutaneous implant (not injection) | Topical (eye creams, gels, serums) |
| Typical Duration | Long-term / as needed before sun season | 28-60 days in manufacturer studies; ongoing use to maintain any effect |
| Best Time to Take | Before the sunny season (approved implant); evening for unapproved injectables | Morning and evening, gently patted under the eyes |
Possible Side Effects May vary by individual |
|
|
| Research Summary | This is one of the few peptides on this list with gold-standard human evidence. The pivotal data came from two multicenter, randomized, double-blind, placebo-controlled trials published in the New England Journal of Medicine in 2015 (Langendonk et al., 373(1):48-59), enrolling 168 EPP patients across the EU (74) and US (94) who received the 16 mg implant or placebo every 60 days. Afamelanotide significantly increased pain-free time in sunlight (median 69.4 vs 40.8 hours in the US trial; 6.0 vs 0.8 hours in the EU trial, where phototoxic reactions also dropped from 146 to 77), and improved disease-specific quality of life, with mostly mild adverse events. Long-term observational follow-up of EPP patients has supported continued benefit and an acceptable safety profile. Clinuvel is also running a phase 3 vitiligo trial (CUV105), with topline results guided for December 2026. The big caveats: this approval is narrowly for EPP, not for cosmetic tanning, and the unregulated injectable 'Melanotan' products people buy online are not the same controlled, clinician-administered implant and carry real risks. Bottom line: a genuinely proven, approved drug for a rare condition, frequently misused outside that lane. | We could not find an independent, peer-reviewed clinical trial of acetyl tetrapeptide-5. The evidence is manufacturer data reported in trade publications. Lipotec's best-known study used a 1% Eyeseryl cream on one eye and placebo on the other in male volunteers aged 30 to 65, twice daily for 28 days, and reported about a 30% reduction in under-eye puffiness volume, with most volunteers rating it positively. Another supplier document describes a 60-day study in 20 women using a cream with a very low peptide level, scored from photos by a dermatologist. Other summaries quote different numbers (17% to 21%) from studies we could not trace to an original paper. The studies differ in concentration, sex, length and how puffiness was measured, so they cannot be pooled. Independent ingredient databases rate the evidence as limited for exactly this reason. Bottom line: plausible for mild fluid puffiness, cheap to try in an eye cream, but not a fix for true eye bags and not backed by independent trials. |
Frequently Asked Questions: Melanotan I vs Acetyl Tetrapeptide-5
What is the difference between Melanotan I and Acetyl Tetrapeptide-5?
Melanotan I is a skin & hair peptide that melanotan i is the research name for afamelanotide (code cuv1647), a 13-amino-acid synthetic analog of alpha-melanocyte-stimulating hormone (alpha-msh), also written as [nle4, d-phe7]-alpha-msh or ndp-msh. sold as scenesse, it was approved by the ema in 2014 and the fda in 2019 to increase pain-free light exposure in adults with erythropoietic protoporphyria (epp), one of a few approved melanocortin drugs alongside bremelanotide (vyleesi) and setmelanotide (imcivree). the approval covers only the 16 mg bioresorbable implant placed under the skin by a clinician. the injectable 'melanotan i' sold online is not approved for anything. Acetyl Tetrapeptide-5 is a skin & hair peptide that acetyl tetrapeptide-5 is a short synthetic peptide sold by lipotec (now lubrizol) as eyeseryl, made for eye creams that target under-eye puffiness. the pitch is that it reduces fluid leaking into the tissue under the eyes. it is a cosmetic ingredient, and nearly all of the human data comes from the company that sells it. The main differences lie in their mechanisms of action and clinical applications.
Which is better, Melanotan I or Acetyl Tetrapeptide-5?
Neither is universally "better" - the choice depends on your specific goals. Melanotan I is typically used for skin & hair purposes, while Acetyl Tetrapeptide-5 is used for skin & hair. Always consult with a healthcare provider to determine which may be appropriate for your situation.
Can Melanotan I and Acetyl Tetrapeptide-5 be used together?
Some peptide protocols combine multiple compounds for synergistic effects. However, using Melanotan I and Acetyl Tetrapeptide-5 together should only be considered under medical supervision, as both compounds have their own side effect profiles and potential interactions. Research on their combined use may be limited.