Dermorphin
A potent opioid peptide from frog skin, tested once in surgery in 1985 and now known mainly as a racehorse doping agent
Dermorphin is a seven-amino-acid opioid from the skin of South American Phyllomedusa frogs, unusual for carrying a D-amino acid. In lab tests it was about 40 times more potent than morphine, and in one 1985 surgical trial its spinal injection gave longer pain relief than morphine. It was never developed, and today it turns up as a doping agent.
What is it?
Dermorphin was isolated from the skin of Amazonian Phyllomedusa frogs by Vittorio Erspamer's group, the same frog secretions used in the traditional 'kambo' ritual. It was one of the first natural peptides found to contain a D-amino acid, a D-alanine at position 2, which protects it from breakdown. Erspamer's group later found related frog peptides, the deltorphins, that target delta rather than mu opioid receptors.
Its potency is striking. In the classic organ-bath tests used to rank opioids, dermorphin was about 39 to 40 times more potent than morphine. Like morphine, it acts on mu-opioid receptors, which means it carries the same risks of respiratory depression, overdose and dependence.
It was tested in people once. In a 1985 randomised double-blind study of 150 patients after elective surgery, a single 20-microgram spinal injection of dermorphin relieved pain for about 43 hours, against about 34 hours for spinal morphine and 11 hours for routine injected pentazocine, with similar side effects. A 2018 review noted that this study was almost never cited and argued for re-examining dermorphin; it has not been developed since.
Its modern notoriety comes from horse racing, where it has been used illegally to dull pain in racehorses; anti-doping laboratories have built tests for dermorphin and its analogues in horse and human urine. Racing authorities prohibit it. Dermorphin is not an approved medicine anywhere, and any vial sold under its name is an unregulated, potentially lethal opioid.
At a Glance
Every value in this table is printed from the Grey Peptides dataset, the same record the compound explorer and comparison tool read, so the three can never disagree.
Educational information, not medical advice. The doses on this page come from approved labels, published studies and, where no study exists, amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
Published Research
These studies were read from their PubMed abstracts on October 5, 2026.
Spinal dermorphin after surgery, 150 patients
In a prospective randomised double-blind study, intrathecal dermorphin 20 µg gave pain relief lasting 43.4 hours, against 34.5 hours with intrathecal morphine 500 µg and 10.8 hours with intramuscular pentazocine; hospital stays were shorter with both spinal opioids, and side effects did not differ.
Ranking its potency
Dermorphin and Hyp6-dermorphin, the first opioid peptides found to contain a D-alanine, were 57,294, 18 and 39 times more potent than Met-enkephalin, Leu-enkephalin, beta-endorphin and morphine respectively on guinea-pig ileum opioid receptors.
A forgotten drug
The authors trace dermorphin from Erspamer's isolation in the early 1980s to the 1985 trial, note that only 15 pharmacological papers mentioned that trial and none clinical, and argue for re-exploring it for intrathecal use in postoperative and palliative pain.
A urine test for human doping control
Noting reported use in humans as well as racehorses, the authors developed and validated screening and confirmation methods for dermorphin and its main metabolite in human urine.
Detecting it in racehorses
A nano-UHPLC-MS/MS method detected dermorphin and six analogues in horse urine at 5 to 50 pg/mL, to support control of their abuse in equine sport.
Side Effects & Contraindications
Reported Side Effects
From the 1985 trial and its pharmacology as a mu-opioid agonist.
Contraindications & Cautions
There is no approved product and no label.
Legal Status
Not approved anywhere; prohibited in sport.
Frequently Asked Questions
?How potent is dermorphin?
In classic lab tests it was about 39 to 40 times more potent than morphine at mu-opioid receptors.
?Has dermorphin been tested in people?
Once: a 1985 trial of 150 surgical patients found spinal dermorphin relieved pain for about 43 hours, longer than spinal morphine. It was never developed further.
?Is dermorphin safe to buy?
No. It is an unapproved, potent opioid; unregulated vials carry a real risk of fatal overdose.
References
- [pubmed] Basso N, et al. "Intrathecal dermorphine in postoperative analgesia." Peptides, 1985;6 Suppl 3:177-9. PMID: 3831962.
- [pubmed] Broccardo M, et al. "Pharmacological data on dermorphins, a new class of potent opioid peptides from amphibian skin." Br J Pharmacol, 1981;73(3):625-31. PMID: 7195758.
- [pubmed] Hesselink JMK, et al. "Rediscovery of old drugs: the forgotten case of dermorphin for postoperative pain and palliation." J Pain Res, 2018;11:2991-2995. PMID: 30538538.
- [pubmed] Castro JL, et al. "A high throughput approach for determination of dermorphin in human urine using liquid chromatography-mass spectrometry for doping control purposes." J Mass Spectrom, 2020;55(10):e4593. PMID: 32805775.
- [pubmed] Richards SL, et al. "Detection and quantification of dermorphin and selected analogs in equine urine." Bioanalysis, 2013;5(24):2995-3007. PMID: 24320126.
- [pubmed] Erspamer V, et al. "Deltorphins: a family of naturally occurring peptides with high affinity and selectivity for delta opioid binding sites." Proc Natl Acad Sci U S A, 1989;86(13):5188-92. PMID: 2544892.
- [manufacturer] Association of Racing Commissioners International (ARCI) and FEI prohibited substances list; dermorphin classified as Class 1 prohibited substance in horse racing.
Sources & Citations
Studies from their PubMed abstracts, read October 5, 2026; racing prohibition from the regulator source in our dataset.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Consult a licensed healthcare provider before making health decisions.