Last updated October 21, 2026. Approval line checked October 21, 2026. No compounding source date is assigned.
FDA status
Not approved
Not approved. This record is not an FDA-approved drug product. Approval, where it exists, is specific to a drug product, indication, and route.
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Evidence tier
Animal Only. The tier is the highest indexed study type. It is not a safety rating and it is not an FDA approval. Confidence score 3/5. 6,174 PubMed citations indexed.
Leu-enkephalin (Tyr-Gly-Gly-Phe-Leu) is an endogenous pentapeptide opioid derived primarily from proenkephalin that acts as a potent agonist at delta-opioid receptors (δOR) and, to a lesser extent, mu
What the literature studies
Immune Research
Evidence tier
Animal Only
Compounding record
Status not verified
Status not verified. No product-specific FDA primary source is recorded for this entry. FDA approval and compounding eligibility are not verified. Research information is not evidence of FDA approval. Approval, where applicable, is specific to a drug product, indication and route. Research information is not evidence of FDA approval. Approval, where applicable, is specific to a drug product, indication and route.
Regulatory source not verified; no checked date is assigned.
Rapid in vivo degradation makes exogenous Leu-enkephalin impractical as a therapeutic without chemical stabilization; mu-opioid receptor activity carries abuse and respiratory depr
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Educational only. Not medical advice. This page does not give doses or sourcing. See the medical and editorial disclaimer.