Harm Reduction: Reagent Testing & Fentanyl Test Strip Guide

Testing your substances can save your life. Many drugs are cut with dangerous adulterants, including fentanyl, fentanyl analogues, or unexpected stimulants/depressants. Reagent testing and fentanyl test strips help you identify what’s really in your substance before you take it.

Reagent Color Reactions

Reagent	What it detects	Color Reactions
Marquis Reagent	MDMA, amphetamines, opioids.	MDMA (Ecstasy, Molly) → Dark purple to black Methamphetamine / Amphetamines → Orange to brown Opioids (Heroin, Morphine, Codeine, etc.) → Dark brown to black
Mandelin Reagent	Ketamine, cathinones ("bath salts"), MDMA, amphetamines, some opioids.	Ketamine → Dark orange to red MDMA / MDA → Green to dark blue Methamphetamine / Amphetamines → Dark green to brown Cathinones ("Bath Salts") → Yellow to green
Mecke Reagent	Opiates, MDMA, LSD, DXM	Heroin / Morphine → Dark green to blue to black Codeine → Green to dark blue MDMA → Blue to black DXM (Dextromethorphan, found in cough syrups and some pills) → Yellow to green
Ehrlich Reagent	LSD and other indoles (e.g., 1P-LSD, ALD-52, DMT, Psilocybin Mushrooms).	LSD & Analogues → Purple Psilocybin (Magic Mushrooms) → Purple (but weaker reaction than LSD) DMT (N,N-Dimethyltryptamine) → Purple or pinkish
Folin Reagent	Differentiates between MDMA and MDA.	MDMA → No color change or slight pink MDA (related to MDMA but more psychedelic) → Brownish to reddish
Simon's Reagent	Differentiates MDMA from MDA.	MDMA / Methamphetamine (secondary amines) → Blue MDA (primary amine) → No color change