What it is
Dermorphin is seven amino acids: tyrosine, D-alanine, phenylalanine, glycine, tyrosine, proline, serine — with the end capped as an amide. It is an opioid: it binds the μ-opioid receptor, the target of morphine and of the body's own enkephalins.
Frogs make it. South American leaf frogs of the genus Phyllomedusa secrete it in their skin, and in 1981 Pier Cesare Montecucchi, Roberto de Castiglione and Vittorio Erspamer reported its sequence from Phyllomedusa sauvagei (PMID 7287299). A second paper that year found it, alongside a hydroxyproline variant, in Phyllomedusa rhodei (PMID 7287302).
The mirror-image amino acid
The detail that made dermorphin famous among chemists is its second residue: D-alanine.
Amino acids come in two mirror-image forms, L and D. Animal cells build proteins from L forms only. In 1987 Richter, Egger and Kreil cloned the frog's dermorphin precursors and found an ordinary alanine codon (GCG) at that position (Science, PMID 3659910): the frog builds L-alanine and flips it to D afterwards. Each precursor carries repeats of 35 amino acids, with one copy of the heptapeptide in each. A 1987 binding study in rat brain called dermorphin "the most potent of the naturally occurring opioid peptides" (Amiche et al., PMID 2825686), binding its sites at sub-nanomolar affinity (Kd 0.86 nM).
The D-Ala-at-position-2 motif became a starting point for synthetic opioid peptides. Chemists in the early 1980s were already making shortened dermorphin "tetrapeptide amides" built on H-Tyr-D-Ala-Phe-Gly (Salvadori 1982, PMID 7140967).
What the research covers
PubMed returns 535 records for dermorphin (2026-10-28), mostly 1980s–2000s pharmacology: pain relief, gut secretion and breathing in rats, receptor binding, analogue design. A 2015 paper notes that IV dermorphin produces central and peripheral effects in rats, dogs and humans. No trial is registered on ClinicalTrials.gov, and the compound never became a medicine.
Why it shows up in racing
The most recent strand of the literature is forensic. Robinson and colleagues at the University of Pennsylvania's equine toxicology laboratory gave dermorphin to ten horses at about 9.3 μg/kg (PMID 25376170), noting that it "has been identified in postrace horse samples":
| Measure | Result |
|---|---|
| Elimination half-life, IV | 0.76 h |
| Terminal half-life, IM | 0.68 h |
| IM bioavailability | 47–100% (3 horses) |
| Share excreted in urine | ~5% |
| Effect after IV dose | Excitation and raised heart rate, gone within 5 minutes |
| Detectable in plasma | 12 h |
| Detectable in urine | 48–72 h |
Racing laboratories have since published screens for dermorphin and up to 17 related peptides in equine plasma and urine (e.g. Steel 2014, PMID 24259424). A 2024 case report described a synthetic dermorphin tetrapeptide, [Dmt¹]-DALDA, in a seized unlabelled vial and in horse urine (PMID 37408356) — the analogue chemistry of the 1980s turning up in a doping case.
Where it stands
Approved as a medicine: nowhere.
Human evidence: pharmacology noted in reviews; no registered trial.
Main present-day context: equine doping control.
It is an opioid. Any opioid carries the receptor's known risks, including slowed breathing; this entry describes the molecule and does not report amounts for people.
Last checked
2026-10-28.