Comparison
Afamelanotide vs. Sekretin
Two peptides side-by-side — identity, evidence base, legal status and known adverse events.
Identity
Category
Research other
Research other
CAS no.
75921-69-6
no data
Molecular weight
1646.87 g/mol
3055.5 g/mol
Half-life
12 h
no data
Sequence
Ac-Ser-Tyr-Ser-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2no data
Mechanism of action
Afamelanotide
Afamelanotide is a synthetic analogue of α-melanocyte-stimulating hormone. It differs from native α-MSH by two substitutions — norleucine at position 4 and D-phenylalanine at position 7 — which make it metabolically more stable and more potent. As an agonist at the melanocortin-1 receptor (MC1R) on melanocytes, it activates adenylate cyclase, raises cAMP and increases tyrosinase activity via the transcription factor MITF. This shifts pigment synthesis toward eumelanin, which absorbs UV and visible light and has antioxidant properties — the presumed mechanism of photoprotection in EPP.
Sekretin
Secretin binds the Gs-coupled secretin receptor (SCTR) on pancreatic duct cells, opens CFTR chloride channels and triggers secretion of bicarbonate-rich pancreatic fluid and bile flow.
Evidence base
Highest evidence
Human RCT
Human trial
Studies
4
0
of which in humans
4
0
Effects recorded
4
2
Open conflicts
1
0
Documented adverse events
4
1
Legal status
Full entries
Frequently asked questions
- What is the difference between Afamelanotide and Sekretin?
- Afamelanotide is classified as "Research other", while Sekretin is classified as "Research other". Afamelanotide: Afamelanotide (brand name Scenesse) is a synthetic 13-amino-acid analogue of α-melanocyte-stimulating hormone (α-MSH) and a melanocortin-1 receptor agonist. Unlike most peptides covered here, it is a regularly approved medicine: EMA approval in 2014/2015, FDA approval in 2019, in each case as a subcutaneous implant for the prevention of phototoxicity in adults with erythropoietic protoporphyria (EPP). It promotes eumelanin formation in the skin. Sekretin: Secretin is a 27-amino-acid hormone that regulates pancreatic bicarbonate secretion. As ChiRhoStim it is FDA-approved as a diagnostic agent (pancreatic function test, gastrinoma test, secretin-enhanced MRCP). This page contrasts both neutrally and source-based — with no usage or dosing recommendation.
- Which peptide is better supported by science, Afamelanotide or Sekretin?
- The highest available evidence level is "Human RCT" for Afamelanotide and "Human trial" for Sekretin. A higher evidence level means more robust data, but says nothing about suitability for an individual. The full body of evidence is on each peptide's own page.
- What is the legal status of Afamelanotide and Sekretin in Germany and the United States?
- Germany: Afamelanotide — Prescription, Sekretin — Prescription. United States: Afamelanotide — Prescription, Sekretin — Prescription. These are factual summaries with source and review date on the individual pages.