As of July 18, 2026, Endomorphin-1 is legal to sell at retail in Washington. Unscheduled - legal as research-use-only; no operative instrument reaches a structurally-dissimilar opioid peptide. Controlling source: RCW 69.50.101(16) (controlled substance analog; offense 69.50.214; human-consumption gate).
Verified July 18, 2026 · confidence: confirmedEndomorphin-1 (Tyr-Pro-Trp-Phe-NH2) is not named or scheduled in Washington. The state has a controlled-substance analogue statute whose similarity test is CONJUNCTIVE (chemical structure substantially similar to a scheduled substance AND a substantially similar CNS effect). The structure prong fails for a tetrapeptide, so the statute does not reach EM-1. Controlling instrument reviewed: RCW 69.50.101(16) (controlled substance analog; offense 69.50.214; human-consumption gate). Conclusion: no operative instrument reaches a structurally-dissimilar endogenous opioid peptide; status LEGAL at the state controlled-substances level. Residual risk: minimal. Federal floor still applies (Analogue Act human-consumption contingency + FD&C unapproved-new-drug).
RCW 69.50.101(16): "'Controlled substance analog' means a substance the chemical structure of which is substantially similar to the chemical structure of a controlled substance in Schedule I or II AND: (i) that has a stimulant, depressant, or hallucinogenic effect on the central nervous system substantially similar to [that] of a controlled substance included in Schedule I or II; or (ii) ... that the individual represents or intends to have [such] effect ..." (69.50.214: analog treated as Schedule I to the extent intended for human consumption). [Conjunctive - structure prong fails; human-consumption gate.]
Among Washington's 2 neighbors, Idaho and Oregon are legal, the same posture as Washington.
Open the interactive map · Every compound in Washington
Not federally scheduled. Endomorphin-1 - not federally scheduled; endogenous opioid tetrapeptide, no CSA entry and no analogue-act structural hook Federal detail
2 instruments on file for this compound's framework in Washington; 2 of 2 citations above are official sources. Each text carries its source and a fingerprint that changes when the law does.
f2016f99bbc64a47**RCW 69.50.204(c) (hallucinogen chapeau + isomer definition)** — "Hallucinogenic substances. Unless specifically excepted or unless listed in another schedule, any material, compound, mixture, or preparation which contains any quantity of the following hallucinogenic substances, including their salts, isomers, and salts of isomers whenever the existence of those salts, isomers, and salts of isomers is possible within the specific chemical designation. For the purposes of this subsection only, the term 'isomer' includes the optical, position, and geometric isomers" — RCW 69.50.204(c), https://app.leg.wa.gov/RCW/default.aspx?cite=69.50.204&pdf=true (OFFICIAL — certified 7/12/2024). Psilocyn and psilocybin are listed; 4-HO-MET is not. **RCW 69.50.101(16) (controlled substance analog)** — "'Controlled substance analog' means a substance the chemical structure of which is substantially similar to the chemical structure of a controlled substance in Schedule I or II and: (i) that has a stimulant, depressant, or hallucinogenic effect on the central nervous system substantially similar to the stimulant, depressant, or hallucinogenic effect on the central nervous system of a controlled substance included in Schedule I or II; or (ii) with respect to a particular individual, that the individual represents or intends to have a stimulant, depressant, or hallucinogenic effect on the central nervous system substantially similar to [that] of a controlled substance included in Schedule I or II." — RCW 69.50.101(16), https://app.leg.wa.gov/RCW/default.aspx?cite=69.50.101&pdf=true (OFFICIAL — certified 8/15/2025).
b89d8e66c22f4597RCW 69.50.214. Controlled substance analog. A controlled substance analog, to the extent intended for human consumption, shall be treated, for the purposes of this chapter, as a substance included in Schedule I. Within thirty days after the initiation of prosecution with respect to a controlled substance analog by indictment or information, the prosecuting attorney shall notify the commission of information relevant to emergency scheduling as provided for in RCW 69.50.201(e). After final determination that the controlled substance analog should not be scheduled, no prosecution relating to that substance as a controlled substance analog may continue or take place. RCW 69.50.101(16)(a). "Controlled substance analog" means a substance the chemical structure of which is substantially similar to the chemical structure of a controlled substance in Schedule I or II and: (i) that has a stimulant, depressant, or hallucinogenic effect on the central nervous system substantially similar to the stimulant, depressant, or hallucinogenic effect on the central nervous system of a controlled substance included in Schedule I or II; or (ii) with respect to a particular individual, that the individual represents or intends to have a stimulant, depressant, or hallucinogenic effect on the central nervous system substantially similar to the stimulant, depressant, or hallucinogenic effect on the central nervous system of a controlled substance included in Schedule I or II.
Compound Laws, published by Compound Analytics, reports the record: statutes verbatim, official citations, enforcement facts and verification dates. Nothing here is legal advice and nothing here describes how to get around a law. A jurisdiction with no verified row is reported as not yet verified, never as legal. Found an error? Corrections policy.
About · Methodology · Glossary · Changes · Data & API · llms.txt · Sitemap