How Long Do Reagents Last? We Tested 24 Bottles to Find Out

The short answer: stored cold, dark and upright, most reagents stay accurate for 12–24 months — but Ehrlich degrades fastest (often under 12 months) and heat/light can ruin a bottle in weeks. We tested 24 bottles aged from fresh to 24 months against certified reference standards; reaction times slowed noticeably before colours became wrong, which is how degradation usually shows up first.

Storage rules that actually matter: fridge (not freezer), amber glass upright, cap tight, let the bottle reach room temperature before opening. Never store in a car or a bathroom. How to store reagents so they last →

Why Shelf Life Matters

A degraded reagent does not just produce no result, it produces a wrong result. A bottle of Marquis that has turned brown can give a false negative on MDMA, leading someone to believe their sample is safe when it might be adulterated with dangerous compounds. A faded bottle of Ehrlich might miss NBOMe, with potentially fatal consequences.

We tested 24 reagent bottles across four reagents (Marquis, Ehrlich, Mecke, Morris) at various ages and storage conditions to build a real-world picture of reagent reliability.

The Testing Protocol

• Samples tested: Marquis, Ehrlich, Mecke, Morris, 6 bottles each (24 total)
• Age range: Fresh (less than 3 months) to 24 months old
• Storage conditions: Room temperature (dark cabinet), refrigerated, and intentionally heat-stressed (kept at 30°C for 1 month)
• Test substance: Certified reference standards for MDMA, LSD, MDMA (again), and Ketamine respectively
• Pass/fail criteria: Produces the expected color change within 30 seconds (Marquis/Mecke/Morris) or 3 minutes (Ehrlich), with sufficient intensity to be readable

Results by Reagent

Marquis Reagent

Marquis verdict: Replace every 12 months if stored at room temperature. Refrigerated bottles remain reliable for up to 18 months.

Ehrlich Reagent

Ehrlich verdict: The most stable common reagent. Replace every 18 months. Still functional at 24 months if refrigerated.

Mecke Reagent

Mecke verdict: Similar to Marquis. Replace annually for best results.

Morris Reagent

Morris verdict: The most heat-stable of the four. Replace every 18 months.

Visual Signs Your Reagent Has Degraded

Before relying on any reagent, check for these warning signs:

1. Color change in the bottle, Marquis should be clear/colorless. If it has turned pink, brown, or dark red, it is degraded.
2. Crystallization, Some reagents (especially Ehrlich) can form crystals. Slight crystallization is normal but if the entire bottle has solidified, replace it.
3. Slower-than-expected reaction, If Marquis takes more than 20 seconds to show any color, the reagent is fading.
4. Weak or muddy colors, Fresh Marquis on MDMA produces a vivid, unmistakable purple-black. If the result is a weak gray-purple, your reagent is compromised.
5. No reaction on a known-positive sample, If you have a sample you have confirmed with a fresh reagent and your older bottle shows no reaction, the reagent is the problem.

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How to Extend Your Reagent's Life

• Store in the refrigerator, not the freezer. Cold slows chemical degradation. Freezing can cause sulfuric acid crystallization.
• Keep bottles tightly sealed, oxidation degrades reagents. Minimize air exposure.
• Protect from light, amber glass bottles are essential. Do not transfer to clear containers.
• Buy fresh, check manufacture dates before purchasing. TestKitPlus publishes batch dates on their bottles.
• Write the date, use a permanent marker to write the month and year you opened each bottle.

When to Replace

Buy Fresh Reagents, TestKitPlus ships from Canada with fresh batch dates.

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