Leu-enkephalin vs Cosyntropin

Head-to-head comparison of Leu-enkephalin (Tyr-Gly-Gly-Phe-Leu) and Cosyntropin (Cosyntropin (ACTH 1-24)) — benefits, dosing, side effects, research data, and where to buy.

Research Score

PropertyLeu-enkephalinCosyntropin
CategoryPain ManagementPain Management
Full NameTyr-Gly-Gly-Phe-LeuCosyntropin (ACTH 1-24)
Molecular Weight555.63 Da2933.3 Da
Half-Life1-5 minutes in plasma~10 min
Amino Acids524
Typical Dose0.1-5 ug per animal0.25 mg IV/IM diagnostic dose|off-label headache protocols vary
RouteIntrathecal / intracerebroventricularIV|IM
Purity≥98%≥98%
Studies Count100061
Research StatusPre-clinicalClinical research

Leu-enkephalin Benefits

  • delta-opioid activity
  • endogenous analgesic model
  • receptor-selective pharmacology
  • nociception pathway research

Cosyntropin Benefits

  • refractory migraine
  • anti-inflammatory signaling
  • headache rescue research

Leu-enkephalin Dosing

Intrathecal 0.1-5 ug per animal|Intracerebroventricular 0.1-2 ug per animal|In vitro 1-100 nM

Cosyntropin Dosing

0.25 mg IV/IM|1 mg IV/IM

Leu-enkephalin Side Effects

  • sedation
  • constipation-like opioid effects
  • very short plasma stability

Cosyntropin Side Effects

  • flushing
  • nausea

Research Overview

Leu-enkephalin

Leu-enkephalin is a standard tool in opioid receptor and pain-transmission research because it helps distinguish delta- from mu-preferring signaling. Its research value is high, but its clinical utility is limited by rapid enzymatic breakdown and delivery challenges.

Cosyntropin

Cosyntropin is not a standard pain drug, but it appears in headache literature because ACTH analogs can help some patients with difficult migraine attacks. The analgesic rationale is partly tied to steroidogenic and anti-inflammatory effects.

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Common Stacking Partners

Leu-enkephalin stacks with:

gabapentinketamine

Cosyntropin stacks with:

ACTH(1-24)Synacthen
opioid-peptideenkephalindelta-opioidanalgesiamigraineheadacheACTH-analog