α-MSH
Also known as: Alfa-MSH, α-Melanotropina
Molecular Identifiers
Molecular Formula
C77H109N21O19S
CAS Number
581-05-5
PubChem CID
16133793Molecular Weight
1664.82 Da
Overview
Alpha melanocyte-stimulating hormone, an endogenous 13-amino acid peptide derived from pro-opiomelanocortin (POMC). Acts on multiple melanocortin receptors with functions in pigmentation, anti-inflammation, and immunomodulation.
α-MSH has two axes of clinical interest: skin pigmentation (via MC1R) and potent anti-inflammatory/immunomodulatory action (via MC1R-MC5R, with NF-κB inhibition). It is researched in inflammatory and autoimmune conditions, as well as in photosensitivity. Its plasma half-life is very short (minutes), which limits direct use and motivated the development of synthetic analogs such as Melanotan I (afamelanotide) and Melanotan II.
The endogenous form of α-MSH has no regulatory approval for therapeutic use — what reached the market was its analog afamelanotide (Scenesse) for erythropoietic protoporphyria. The use of α-MSH in research is typically subcutaneous, in short 2-4 week cycles. The C-terminal fragment KPV (amino acids 11-13) retains anti-inflammatory activity and is studied separately as a derived peptide.
As the endogenous ligand of the pathway, α-MSH is the biological reference against which analogs are measured: Melanotan I (afamelanotide) preserves MC1R selectivity with a useful half-life, Melanotan II broadens the spectrum to MC3R/MC4R/MC5R (gaining sexual and central effects in the process), PT-141 (bremelanotide) focuses on MC4R for sexual function, and setmelanotide is an MC4R-selective agonist for monogenic obesity. α-MSH itself remains a research tool given its very short half-life.
SYSMEHFRWGKPV Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val Half-life
~20-30 minutes
Administration Route
Subcutaneous
Category
Hormonal Regulation
Mechanism of Action
- Agonism of MC1R to MC5R receptors (melanocortins)
- Stimulation of melanogenesis and melanin production
- Potent anti-inflammatory effect via NF-κB inhibition
- Immunomodulation and cytokine regulation
- Modulation of feeding behavior via MC4R
- Regulation of energy homeostasis
Dosage Protocol
Data compiled from the literature. This does not constitute medical advice.
| Parameter | Value |
|---|---|
| Dose | 0.5-2 mg per injection |
| Frequency | Once daily or every other day |
| Timing | Any time of day |
| Duration | 2-4 weeks |
Reported Side Effects
Adverse effects described in the literature. Severity and frequency vary between individuals.
- Nausea
- Facial flushing
- Hyperpigmentation
- Fatigue
Product Properties
| Purity | >98% |
| Appearance | White lyophilized powder |
| Solubility | Soluble in water and bacteriostatic water |
| Source | Solid-phase peptide synthesis (SPPS) |
| Storage | Lyophilized: -20°C for up to 2 years, 2-8°C for up to 6 months. Reconstituted: 2-8°C for up to 4 weeks. Protect from light and moisture. Avoid repeated freeze-thaw cycles. |
Presentations & Preparation
Vials of α-MSH found in the research market:
Reconstitution
- Diluent: Bacteriostatic water
- Volume: 2 ml per vial
- Slowly inject the diluent against the vial wall
- Gently swirl until fully dissolved
- Never shake
Storage
- Lyophilized: Refrigerated 2-8°C
- Reconstituted: Refrigerated 2-8°C (up to 14 days)
- Protect from direct light
- Do not freeze after reconstitution
- Short half-life peptide - use promptly
Scientific Studies
Published studies on α-MSH.
Targeting melanocortin receptors as a novel strategy to control inflammation
Catania A, Gatti S, Colombo G, Lipton JM
Melanocortin receptors - identification and characterization by melanotropic peptide agonists and antagonists
Hadley ME, Hruby VJ, Jiang J, Sharma SD, Fink JL, Haskell-Luevano C, Bentley DL, al-Obeidi F, Sawyer TK
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