Peptide profile
Dermorphin
Potent frog-derived mu-opioid receptor agonist · also known as Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH2, Dermorphin heptapeptide
Compare Dermorphin with other peptides →Summary
Dermorphin is a naturally occurring heptapeptide opioid first isolated from the skin of South American Phyllomedusa frogs. It binds with extraordinarily high selectivity and potency to mu-opioid receptors, producing analgesic effects estimated to be 30–40 times more potent than morphine on a molar basis. Research has primarily been conducted in animal models, with extremely limited controlled human data available.
- Typical dose
- Research doses in animal studies: 1–10 mcg/kg; no established human dosing protocol
- Half-life
- ~20–40 minutes (animal data); prolonged vs. endogenous opioids due to D-Ala residue
- Route
- Subcutaneous, Intramuscular
- Cycle length
- Not established for humans; acute dosing only in research contexts
Mechanism
How it works
Dermorphin acts as a highly selective full agonist at mu-opioid receptors (MOR, OPRM1), activating Gi/o protein-coupled signaling cascades that reduce adenylyl cyclase activity, decrease intracellular cAMP, hyperpolarize neurons via GIRK channels, and inhibit voltage-gated calcium channels. This results in profound suppression of pain signal transmission in both the spinal cord and supraspinal regions. Its unusual D-amino acid (D-Ala at position 2) confers exceptional resistance to enzymatic degradation, prolonging its biological activity compared to endogenous opioid peptides.
Reported in research
Benefits
- Exceptionally potent analgesia with mu-opioid receptor selectivity (animal studies)
- Prolonged duration of action due to D-amino acid-mediated enzymatic resistance
- Potential reduction in nociceptive signaling with lower administered doses than classical opioids
- Research tool for investigating mu-opioid receptor pharmacology and pain pathways
Context, not a prescription
Dosing
- Typical range
- Research doses in animal studies: 1–10 mcg/kg; no established human dosing protocol (Subcutaneous, Intramuscular)
- Cycle length
- Not established for humans; acute dosing only in research contexts
- Half-life
- ~20–40 minutes (animal data); prolonged vs. endogenous opioids due to D-Ala residue
Safety
Side effects & contraindications
Possible side effects
- Respiratory depression (dose-dependent, potentially severe)
- Nausea and vomiting
- Sedation and CNS depression
- Physical dependence and withdrawal with repeated use
- Bradycardia and hypotension
- Miosis
- Constipation and gastrointestinal dysmotility
- Tolerance development with repeated dosing
Contraindications
- Respiratory insufficiency or chronic obstructive pulmonary disease
- Concurrent use of CNS depressants, benzodiazepines, or other opioids
- History of opioid use disorder or substance dependence
- Pregnancy or breastfeeding
- Hepatic or renal impairment affecting drug clearance
- Use of MAO inhibitors within 14 days
Research information, not medical advice. Always consult a licensed clinician before considering any peptide.
In depth
Full profile
What it does
Profound pain relief, deep sedation, slowed breathing, reduced heart rate, and a sense of calm or euphoria are expected based on its opioid mechanism.
How it works
Imagine your brain's pain receptors are like combination locks on a door labeled 'Pain Signal.' Morphine is a key that opens this lock reasonably well. Dermorphin is like a master key that fits the same lock but opens it with much less effort and holds the door shut far longer — meaning even a tiny amount can have a big effect.
After injection, dermorphin travels through the bloodstream and crosses into the brain, where it binds tightly to opioid receptors. This quiets the nerve cells responsible for relaying pain messages, causing strong pain relief, sedation, and feelings of calm. Because it has an unusual building block (a D-amino acid) that enzymes struggle to break down, it lasts longer in the body than most natural pain-relief peptides.
What to expect
Effects are typically felt within minutes of injection in animal studies. Precise human onset data is unavailable.
- Minutes 1–15: Rapid onset of analgesia and sedation following injection, based on animal pharmacokinetic data
- Minutes 15–90: Peak effect window; pronounced pain suppression and sedation persist due to enzymatic resistance of the D-Ala residue
- Hours 2–6+: Gradual offset of effects; repeated dosing would risk tolerance and physical dependence development
Good to know
- This compound is for research purposes only and should not be self-administered
- If handled in a research context, always have naloxone (opioid reversal agent) immediately available
- Never combine with alcohol, benzodiazepines, or other CNS depressants
Staying safe
- Drowsiness and heavy sedation
- Nausea or vomiting
- Slowed or difficult breathing
- Low blood pressure and slow heart rate
Avoid if you have:
- Anyone with breathing problems or lung disease
- People with a history of addiction or opioid dependence
- Pregnant or breastfeeding individuals
- Anyone taking other sedatives, sleep aids, or opioid medications
Mechanism of action
Dermorphin (Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH2) is a full agonist at the mu-opioid receptor (MOR/OPRM1) with a Ki in the sub-nanomolar range (~0.1–1 nM) and a selectivity ratio vs. delta-opioid receptor (DOR) exceeding 100-fold. Upon MOR binding, dermorphin promotes Gαi/o dissociation, leading to inhibition of adenylyl cyclase (AC), reduced cAMP production, activation of inwardly rectifying GIRK potassium channels causing membrane hyperpolarization, and inhibition of presynaptic N-type and P/Q-type voltage-gated calcium channels (VGCCs). This multimodal suppression of neuronal excitability inhibits the release of excitatory neurotransmitters (glutamate, substance P) in dorsal horn laminae I and II, and modulates descending pain pathways via periaqueductal gray (PAG) and rostral ventromedial medulla (RVM). The D-alanine substitution at position 2 renders the peptide resistant to aminopeptidases and endopeptidases, dramatically extending its half-life relative to Leu- and Met-enkephalin.
Following parenteral administration, dermorphin distributes rapidly to CNS compartments due to its moderate lipophilicity and small molecular size. Receptor occupancy studies in rodents demonstrate saturation of spinal and supraspinal MOR populations at doses of 1–5 mcg/kg subcutaneously. MOR activation in the nucleus accumbens shell additionally engages dopaminergic reward circuitry via disinhibition of GABAergic interneurons projecting to ventral tegmental area (VTA) dopamine neurons, contributing to reinforcing and potentially addictive properties. Respiratory depression results from MOR activation in the pre-Bötzinger complex of the brainstem, a primary center for respiratory rhythm generation.
Pharmacodynamics
In rodent models, antinociceptive effects (hot-plate, tail-flick assays) are maximal within 10–20 minutes of subcutaneous administration. Intrathecal delivery produces near-immediate (1–3 minute) spinal analgesia. No formal human pharmacokinetic data exist; extrapolated plasma half-life in rodents is approximately 20–40 minutes, substantially longer than Leu-enkephalin (~2 minutes) due to D-Ala enzymatic resistance.
Quantifiable antinociception (50–100% inhibition of nociceptive responses at 1–5 mcg/kg in rodents), EEG slowing consistent with deep sedation, reduced respiratory rate and tidal volume, decreased GI motility, hypothermia, and catalepsy at high doses. Chronic dosing produces classical opioid receptor downregulation and desensitization (beta-arrestin-2 recruitment, receptor internalization via GRK2/3 phosphorylation), resulting in analgesic tolerance.
Timeline
- Days 1–3 (acute dosing, rodent model): Peak MOR engagement, maximum antinociception. Cmax achieved within 10–20 minutes subq. Early signs of cAMP pathway inhibition and GIRK channel activation detectable in electrophysiology recordings.
- Days 4–14 (repeated dosing): Progressive analgesic tolerance via GRK2/3-mediated MOR phosphorylation, beta-arrestin-2 recruitment, and receptor internalization. Upregulation of adenylyl cyclase isoforms (AC1, AC8) as compensatory neuroadaptation begins.
- Weeks 2–8: Established physical dependence in rodent models with withdrawal precipitated by naloxone showing classical signs (jumping, wet-dog shakes, weight loss). MOR density and G-protein coupling efficiency reduced. Long-term neuroplastic changes in reward circuitry documented in chronic rodent studies.
Comparisons
- Dermorphin — effectiveness Very High, safety Caution, cost $$, High to use
- DALDA ([D-Arg2]dermorphin tetrapeptide analog) — effectiveness High, safety Caution, cost $$$, High to use
Adverse effects
Common:
- Dose-dependent respiratory depression via pre-Bötzinger complex MOR activation
- Constipation and prolonged GI transit due to peripheral MOR activation in myenteric plexus
- Physical dependence with neuroadaptive changes in cAMP superactivation (adenylyl cyclase sensitization) upon withdrawal
- Mu-receptor-mediated nausea/emesis via area postrema chemoreceptor trigger zone activation
Rare:
- Severe cardiovascular depression including profound bradycardia and hypotension at supratherapeutic doses (incidence undefined in humans)
- Seizure activity paradoxically reported at very high doses in some rodent models, possibly via glycine receptor modulation
Contraindications & risk mitigation
Contraindicated in:
- Individuals with compromised respiratory function (COPD, sleep apnea, neuromuscular respiratory disease)
- Patients on concurrent CYP3A4/CYP2D6 substrates that may affect opioid metabolism
- Individuals with prior opioid use disorder given high reinforcement potential via mesolimbic dopamine pathway activation
- Patients with hepatic cirrhosis affecting peptide catabolism and clearance
- Maintain naloxone (0.4–2 mg IV/IM/intranasal) immediately available whenever dermorphin is handled in any research context
- Implement pulse oximetry monitoring during any in-vivo research administration to detect early respiratory depression
- Use the lowest effective dose paradigm; receptor saturation occurs at very low doses, and dose escalation dramatically increases adverse risk without proportional analgesic gain
- Avoid co-administration with any other CNS or respiratory depressant to prevent synergistic respiratory compromise
Qué hace
Profound pain relief, deep sedation, slowed breathing, reduced heart rate, and a sense of calm or euphoria are expected based on its opioid mechanism.
Cómo funciona
Imagine your brain's pain receptors are like combination locks on a door labeled 'Pain Signal.' Morphine is a key that opens this lock reasonably well. Dermorphin is like a master key that fits the same lock but opens it with much less effort and holds the door shut far longer — meaning even a tiny amount can have a big effect.
After injection, dermorphin travels through the bloodstream and crosses into the brain, where it binds tightly to opioid receptors. This quiets the nerve cells responsible for relaying pain messages, causing strong pain relief, sedation, and feelings of calm. Because it has an unusual building block (a D-amino acid) that enzymes struggle to break down, it lasts longer in the body than most natural pain-relief peptides.
Qué esperar
Effects are typically felt within minutes of injection in animal studies. Precise human onset data is unavailable.
- Minutes 1–15: Rapid onset of analgesia and sedation following injection, based on animal pharmacokinetic data
- Minutes 15–90: Peak effect window; pronounced pain suppression and sedation persist due to enzymatic resistance of the D-Ala residue
- Hours 2–6+: Gradual offset of effects; repeated dosing would risk tolerance and physical dependence development
Bueno saber
- This compound is for research purposes only and should not be self-administered
- If handled in a research context, always have naloxone (opioid reversal agent) immediately available
- Never combine with alcohol, benzodiazepines, or other CNS depressants
Manteniéndose seguro
- Drowsiness and heavy sedation
- Nausea or vomiting
- Slowed or difficult breathing
- Low blood pressure and slow heart rate
Evitar si tienes:
- Anyone with breathing problems or lung disease
- People with a history of addiction or opioid dependence
- Pregnant or breastfeeding individuals
- Anyone taking other sedatives, sleep aids, or opioid medications
Mecanismo de acción
Dermorphin (Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH2) is a full agonist at the mu-opioid receptor (MOR/OPRM1) with a Ki in the sub-nanomolar range (~0.1–1 nM) and a selectivity ratio vs. delta-opioid receptor (DOR) exceeding 100-fold. Upon MOR binding, dermorphin promotes Gαi/o dissociation, leading to inhibition of adenylyl cyclase (AC), reduced cAMP production, activation of inwardly rectifying GIRK potassium channels causing membrane hyperpolarization, and inhibition of presynaptic N-type and P/Q-type voltage-gated calcium channels (VGCCs). This multimodal suppression of neuronal excitability inhibits the release of excitatory neurotransmitters (glutamate, substance P) in dorsal horn laminae I and II, and modulates descending pain pathways via periaqueductal gray (PAG) and rostral ventromedial medulla (RVM). The D-alanine substitution at position 2 renders the peptide resistant to aminopeptidases and endopeptidases, dramatically extending its half-life relative to Leu- and Met-enkephalin.
Following parenteral administration, dermorphin distributes rapidly to CNS compartments due to its moderate lipophilicity and small molecular size. Receptor occupancy studies in rodents demonstrate saturation of spinal and supraspinal MOR populations at doses of 1–5 mcg/kg subcutaneously. MOR activation in the nucleus accumbens shell additionally engages dopaminergic reward circuitry via disinhibition of GABAergic interneurons projecting to ventral tegmental area (VTA) dopamine neurons, contributing to reinforcing and potentially addictive properties. Respiratory depression results from MOR activation in the pre-Bötzinger complex of the brainstem, a primary center for respiratory rhythm generation.
Farmacodinamia
In rodent models, antinociceptive effects (hot-plate, tail-flick assays) are maximal within 10–20 minutes of subcutaneous administration. Intrathecal delivery produces near-immediate (1–3 minute) spinal analgesia. No formal human pharmacokinetic data exist; extrapolated plasma half-life in rodents is approximately 20–40 minutes, substantially longer than Leu-enkephalin (~2 minutes) due to D-Ala enzymatic resistance.
Quantifiable antinociception (50–100% inhibition of nociceptive responses at 1–5 mcg/kg in rodents), EEG slowing consistent with deep sedation, reduced respiratory rate and tidal volume, decreased GI motility, hypothermia, and catalepsy at high doses. Chronic dosing produces classical opioid receptor downregulation and desensitization (beta-arrestin-2 recruitment, receptor internalization via GRK2/3 phosphorylation), resulting in analgesic tolerance.
Cronología
- Days 1–3 (acute dosing, rodent model): Peak MOR engagement, maximum antinociception. Cmax achieved within 10–20 minutes subq. Early signs of cAMP pathway inhibition and GIRK channel activation detectable in electrophysiology recordings.
- Days 4–14 (repeated dosing): Progressive analgesic tolerance via GRK2/3-mediated MOR phosphorylation, beta-arrestin-2 recruitment, and receptor internalization. Upregulation of adenylyl cyclase isoforms (AC1, AC8) as compensatory neuroadaptation begins.
- Weeks 2–8: Established physical dependence in rodent models with withdrawal precipitated by naloxone showing classical signs (jumping, wet-dog shakes, weight loss). MOR density and G-protein coupling efficiency reduced. Long-term neuroplastic changes in reward circuitry documented in chronic rodent studies.
Comparaciones
- Dermorphin — efectividad Very High, seguridad Caution, costo $$, High de usar
- DALDA ([D-Arg2]dermorphin tetrapeptide analog) — efectividad High, seguridad Caution, costo $$$, High de usar
Efectos adversos
Comunes:
- Dose-dependent respiratory depression via pre-Bötzinger complex MOR activation
- Constipation and prolonged GI transit due to peripheral MOR activation in myenteric plexus
- Physical dependence with neuroadaptive changes in cAMP superactivation (adenylyl cyclase sensitization) upon withdrawal
- Mu-receptor-mediated nausea/emesis via area postrema chemoreceptor trigger zone activation
Raros:
- Severe cardiovascular depression including profound bradycardia and hypotension at supratherapeutic doses (incidence undefined in humans)
- Seizure activity paradoxically reported at very high doses in some rodent models, possibly via glycine receptor modulation
Contraindicaciones y mitigación de riesgos
Contraindicado en:
- Individuals with compromised respiratory function (COPD, sleep apnea, neuromuscular respiratory disease)
- Patients on concurrent CYP3A4/CYP2D6 substrates that may affect opioid metabolism
- Individuals with prior opioid use disorder given high reinforcement potential via mesolimbic dopamine pathway activation
- Patients with hepatic cirrhosis affecting peptide catabolism and clearance
- Maintain naloxone (0.4–2 mg IV/IM/intranasal) immediately available whenever dermorphin is handled in any research context
- Implement pulse oximetry monitoring during any in-vivo research administration to detect early respiratory depression
- Use the lowest effective dose paradigm; receptor saturation occurs at very low doses, and dose escalation dramatically increases adverse risk without proportional analgesic gain
- Avoid co-administration with any other CNS or respiratory depressant to prevent synergistic respiratory compromise
Reference data
Specifications
- Molecular formula
- C40H51N7O10
- Molecular weight
- 801.88 g/mol
- Half-life
- ~20–40 minutes (animal data); prolonged vs. endogenous opioids due to D-Ala residue
- Route
- Subcutaneous, Intramuscular
- Cycle length
- Not established for humans; acute dosing only in research contexts
- Storage
- Store lyophilized powder at -20°C, protected from light and moisture. Once reconstituted, store at 4°C and use within 24–48 hours. Avoid repeated freeze-thaw cycles.
- Legal status
- Not approved for human therapeutic use in any jurisdiction. Classified as a controlled or prohibited substance in many countries. Banned by WADA and most equestrian sports authorities due to illicit use in horse racing doping.
FAQ
Common questions
What is the pharmacological basis for dermorphin's superior potency vs. morphine?
Dermorphin's exceptional potency arises from a combination of very high MOR binding affinity (Ki ~0.3 nM vs. morphine ~1–4 nM), full intrinsic efficacy at MOR, and the D-Ala substitution at position 2 that provides resistance to enzymatic degradation. The Tyr-D-Ala pharmacophore optimally fits the MOR orthosteric binding pocket, maximizing receptor activation efficiency. These factors together account for the 30–40-fold potency advantage over morphine observed in rodent antinociception assays (Erspamer et al., Trends Pharmacol Sci, 1981).
Has dermorphin ever been used therapeutically in humans?
There are isolated early clinical reports from the 1980s, primarily from European groups, suggesting intrathecal or epidural dermorphin produced analgesia in cancer pain patients. However, these were small, uncontrolled case series and no randomized controlled trials have been completed. No regulatory authority has approved dermorphin for human therapeutic use, and the research program was largely discontinued due to addiction liability and the availability of other analgesics.
Why is dermorphin prominent in equestrian doping?
Dermorphin came to prominence in equestrian sport doping ('paint' or 'frog juice') because its extreme potency means detection-evading micro-doses could still provide significant analgesic and performance-modifying effects in racehorses. WADA and racing authorities have developed specific immunoassay and LC-MS/MS methods for its detection in equine biological matrices following several high-profile doping scandals in North American and international horse racing circa 2012.
What is the evidence level?
This compound is classified as Animal data. Most data comes from preclinical animal studies. Human clinical trial evidence is limited or absent.
Research
Research & sources
Current evidence for Dermorphin is rated as Animal data. Research is based primarily on animal models.
- 1. Erspamer V, Melchiorri P, Falconieri-Erspamer G et al. — Deltorphins: a family of naturally occurring peptides with high affinity and selectivity for delta opioid binding sites (1989) — Proceedings of the National Academy of Sciences USA 86(13):5188–5192
- 2. Negri L, Melchiorri P, Lattanzi R — Pharmacology of amphibian opiate peptides (2000) — Peptides 21(7):1029–1048
- 3. Broccardo M, Erspamer V, Falconieri-Erspamer G et al. — Pharmacological data on dermorphins, a new class of potent opioid peptides from amphibian skin (1981) — British Journal of Pharmacology 73(3):625–631
- 4. Lazarus LH, Salvadori S — Dermorphin and its analogs (1991) — NIDA Research Monograph 105:138–156