Marquis vs Mecke vs Froehde: Which Reagent Should You Buy First?
Disclosure: we may earn a commission when you buy through links on this page, at no extra cost to you. Our picks are based on the testing protocols used by harm reduction services — never on commission rates.
Top Picks at a Glance
| Award | Product | Price | |
|---|---|---|---|
| Buy First | Marquis Reagent Test Kit — Detects MDMA, Meth, Speed & Opiates | $25.00 | Check Price |
| Buy Second | Mecke Reagent Test Kit | $25.00 | Check Price |
| Buy Third | Froehde Reagent Test Kit | $25.00 | Check Price |
| Skip the Choice | Essential Drug Test Kit (3-in-1) | $60.00 | Check Price |
Three Bottles, Three Jobs
Marquis, Mecke and Froehde get grouped together because they are the three reagents most often used on the same samples, but they are not interchangeable. Each has a chemistry that makes it strong on one drug class and blind on another. Understanding the split is the difference between owning reagents and actually using them well.
Head-to-Head
| Marquis | Mecke | Froehde | |
|---|---|---|---|
| Price | $25.00 | $25.00 | $25.00 |
| Core strength | Broadest screen | Opioids | Cathinones |
| MDMA reaction | Purple → black | Blue → green-black | Green-black → blue-black |
| Amphetamine | Orange → brown | No reaction | Weak/none |
| Heroin | Purple-brown | Blue-green | Purple-brown |
| Cathinones | Weak yellow (easy to misread) | Weak | Distinct yellow → green splits |
| 2C-B | Yellow-green | Brown-green | Green-blue |
| Blind spot | MDMA vs MDA; subtle cathinones | Amphetamines | Amphetamines |
Marquis: The Default First Bottle, $25.00
Marquis (formaldehyde + sulfuric acid) reacts visibly with more drug classes than any other single reagent, which is why nearly every harm reduction service worldwide runs it first.
Mecke: The Opioid Lens, $25.00
Mecke (selenious acid based) shines where Marquis blurs: opioids. Heroin, oxycodone and morphine each produce more distinct color paths under Mecke, and its blue-to-green MDxx reaction is a strong second confirmation for pressed pills.
Froehde: The Cathinone Detector, $25.00
Froehde (molybdic acid based) exists for the modern problem: synthetic cathinones sold as MDMA. Where Marquis gives an ambiguous darkening, Froehde produces distinct yellows and greens that make substitution obvious. It also usefully distinguishes MDMA from MDA, something neither of the other two can do.
The Right Buying Order
- [Marquis](/kits/marquis-reagent), maximum information from bottle one
- [Mecke](/kits/mecke-reagent), adds the opioid lens and MDxx confirmation
- [Froehde](/kits/froehde-test-kit), closes the cathinone gap
Or skip the sequencing entirely: the Essential 3-in-1 swaps Mecke/Froehde for Morris and Ehrlich (adding ketamine and LSD coverage instead), and the 6-in-1 Pro simply includes everything. If your use case is specifically MDMA, the MDMA Complete Kit with Marquis + Simon's + Froehde is the tighter buy, full reasoning in our MDMA guide.
Whichever you choose, read results against the reaction color chart under white light, on a white surface, within the first 30-60 seconds. Color drift after several minutes means nothing.
Frequently Asked Questions
Can I use two reagents on the same sample spot?
No, each reagent needs a fresh, separate sample. Mixing reagents (or dropping onto an already-reacted spot) produces meaningless colors. Use a multi-well ceramic tray and 2-5 mg per well.
Why did my reaction not match the chart exactly?
Cuts and binders shift colors, lighting changes perception, and mixtures react as mixtures. The rule is conservative: if the reaction is not clearly the expected one, treat the sample as unidentified.
Which reagent is best for pressed ecstasy pills?
Run all three if you can, that is the point of the trio. If you own only one, Marquis catches the most dangerous total-substitution cases; Froehde is the strongest single upgrade after it for pills specifically.
Do these reagents expire?
Yes, roughly 1-2 years stored cool and dark. Marquis shows its age by darkening toward brown in the bottle; test a known-clean surface drop if unsure, and replace any bottle whose neat color has visibly changed.
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Last updated 2026-07-17. Prices verified against TestKitPlus at time of update and may change. Testing reduces risk — it never eliminates it.