How to test HEROIN (opioids)?

How to test heroin (opioids): reduce risk by using a ketamine test kit to check it for adulterants. Pure heroin usually looks white but can’t be identified by appearence. To test heroin use reagent tests MarquisMecke, and Froehde in single-use or multiple-use test kits. Reagent tests are simple chemicals that indicate presence of a substance by reacting with different color change to different substances.  To test you need just 1 drop of a reagent and a small sample, about this big -> To detect all ingredients and estimate potency it’s required to use an additional heroin purity test kitTo detect fentanyl or test for fentanyl analogs use the fentanyl test strips.

Reagents presumptively indicate PRESENCE, but not PURITY or QUANTITY. Use different reagent tests to improve accuracy and to detect adulterants – 90% of adulterants will react with 1 out of 3 tests, and 95% with 1 out of 5. To detect all ingredients and estimate potency it’s required to use an additional purity test kitA positive or negative test result does not indicate if the substance is safe. No substance is 100% safe.

How can I test heroin?

Short instructions:

BEFORE using a heroin test kit
  • it’s RECOMMENDED to record the reaction to compare later.
  • if testing a pill, crush it finely and proceed testing using the powder
Heroin testing instructions
  • Take a (small) piece of your powder/pill, about this big -> ●.
  • Put it on a suitable testing plate, preferably a spot test plate or the bottom/underside of a ceramic mug (example). *If using single-use vials insert the sample and observe, as the reagent is already within.
  • Add one (or two) drops of Marquis reagent test (or other supplied) on the sample and wait for the results.
  • Check reagent test results with instructions below.
  • Consider using the TLC Heroin Purity Test Kit to double check possible adulterants and estimate potency.
AFTER using a ketamine test kit
  • OPTIONAL: Pour baking soda over a finished reaction to neutralize used reagents.
  • Wash testing surface under running water.

For full instructions scroll further down below.

VIDEO & RESULTS Watch how to test ketamine

TL;DR: Below is an image with a quick cheat sheet how to use the Heroin Test Kit, and further down you can check out more detailed guide how to test heroin. Use the heroin reagent test results chart to see how to use Marquis reagentMecke and Froehde, and what are the expected results.

All heroin test results:

MARQUIS Reddish violet
MECKE Blueish green
MANDELIN Red > Dark brown
LIEBERMANN Violet > Black
FROEHDE Violet / Red > Black
EHRLICH No color change
HOFMANN No color change
SIMON’S No blue color change
ROBADOPE No pink color change
SCOTT No full color change


Heroin test did not react as expected? Watch out!
All test results are available in our instructions and the TestDrugs app.

STEP ONE How to identify heroin?

What test kit do I need to test heroin?


Reagents can be divided into primary and secondary. Primary reagents react with the expected substance while secondary produce a vibrant color change with an adulterant. Here are a few key notes:

  • Marquis – primary test for most powders, secondary test for cocaine, ketamine, mephedrone and blotters
  • Mecke – primary test for most powders, secondary test for cocaine, ketamine, mephedrone; short shelf life
  • Froehde – primary test for most powders, secondary test for ketamine and amphetamines, long shelf life
  • Fentanyl test strips – secondary test, can detect fentanyl and analogs even if other substances are present as well

Marquis reagent is the main test for opioids and produces a deep purple color change which fades to dark purple or even black. Mecke reagent is the follow up primary test to confirm the presence of heroine, morphine or codeine. Froehde is the final reagent test and tells apart codeine from morphine and heroin.

Ketamine test results with Mandelin reagent, Mecke, Froehde, Liebermann.

Heroin sample reagent tests Marquis, Mecke, Mandelin, Liebermann, Froehde and Zimmermann

Heroin sample of unknown purity after a few minutes
How to use the heroin test kit?
  • Check test results with Marquis test kit: if testing heroin, morphine or codeine there should be a deep purple color change turning darker over time.
  • Next follow up with Mecke and Froehde reagents.
  • Remember to always use the fentanyl test strips.
  • Test as small sample as possible and only try more if you are not getting a conclusive result.

STEP TWO How to test heroin purity?

According to the EMCDDA and most common heroin adulterants are caffeine, fentanyl and random pharmaceuticals. Fentanyl is responsible for many deaths of the opioids epidemic.

Try secondary reagents. Secondary reagents produce a vibrant color change with an adulterant, but not with the expected substance.

Secondary reagent tests for heroin:
How to test MDMA with reagent test Marquis, Simon's and Robadope

Expected pure heroin reagent test results

Pure heroin expected results: purple Marquis, Greenish blue Mecke and brownish Mandelin

Next choose a purity testing kit. It enables you to separate sample into different substances and estimate quantity, however still requires reagent tests to identify detected substances. To discover all adulterants and quantity pair reagents with a TLC (Thin Layer Chromatography) Purity Test Kit. Purity tests alone don’t identify substances and are best paired with 1-2 reagent tests.

TLC Purity Tests:
  • Qualitative: One spot indicates a pure substance. TLC test works by separating substances present in a sample in order to reagent test them individually.  You can also use an already confirmed sample for reference – if both compounds show up at the same height on the TLC “card” that indicates they are the same substance.
  • Semi-quantitative: TLC also helps estimate quantity (potency). The bigger the size of the detected spot, the bigger the amount of measured substance. Note that different substances need different calibrated rulers.
TLC Purity Test potency scale

TLC Purity Test potency scale

  • To estimate heroin purity (number of ingredients and their concentration) use the Substance Purity Test Kit.
  • To precisly estimate MDMA purity use the MDMA Purity Test Kit, which in addition includes a calibrated plastic ruler.

For full TLC (Thin Layer Chromatography) instructions read our guide how to test drugs purity.

FENTANYL How to identify fentanyl?

What is fentanyl?

Fentanyl is an extremely potent and dangerous synthetic opioid, often mixed in street drugs and deadly.

BEFORE using a fentanyl test strip
  • It’s RECOMMENDED to test each and every dose. Because of extreme potency (microgram range) fentanyl is never evenly mixed in. One part of a baggie can be fentanyl free, and another lethal.
How to test fentanyl powder / pills / spice with a fentanyl test strip?
  • Dissolve 100-200 mg in at least 125 ml of water (half a cup).
  • Grab a test strip by blue end and insert it into the liquid, no higher than the thic line.
  • Wait until liquid starts visibly moving up the test strip (up to 15 seconds).
  • Put the test strip away on a flat dry surface and read the result in 2 minutes.
  • Check test strip results: a single line confirms the presence of fentanyl, while two lines (even faint) rule it out.

Fentanyl test did not react as indicated? Watch out!
All test results are available in our instructions and the TestDrugs app.

Looking where to buy a test kit for fentanyl?

FAQ Frequently Asked Questions

Looking where to buy a kit for testing heroin?

List of all Chemical Safety guides how to test drugs:

How to test 2C-B?
How to test MDA?
How to test MDMA?
How to test LSD?
How to test DMT?
How to test FENTANTYL?
How to test COCAINE?
How to test KETAMINE?
How to test MEPHEDRONE?
How to test AMPHETAMINE?
How to test HEROIN (opioids)?
How to test THC and CBD?

and how to detect cuts or other adulterants:

How to detect LEVAMISOLE?
How to detect PMA/PMMA?
How to detect FENTANYL?
How to detect NBOMes?


A positive reaction does not indicate if the substance is safe. Learn more at