How to test THC & CBD (cannabis)?

How to test THC & CBD (cannabis): if you intend to use cannabis (“weed”), first you need a CBD & THC test kit to check their presence and strenght. Cannabis products can come in many different forms and can’t be identified by appearence. To test THC or CBD use the Cannabis reagent test in multiple-use test kits. To detect fentanyl or test for fentanyl analogs it’s recommended to use fentanyl test strips.

How to use the cannabis test kit?

  • Test potency of dry or wet cannabis flowers.
  • Test potency of cannabis oils and other extracts.
  • Compare THC potency with old samples: test results don’t fade.
  • Check for presence of THC to help rule out presence of dangerous adulterants.

NOTE: Cannabis reagent can only test the PRESENCE or QUANTITY, not PURITY of a specific substance. For best results compare CBD or THC potency by testing samples side-by-side.

A positive or negative test result does not indicate if the substance is safe. No substance is 100% safe.

TL;DR: Here is an image with a quick cheat sheet how to use the CBD & THC Test Kit, or check out more detailed guide on how to test methamphetamine further below.

CBD / THC Potency Testing Kit Instructions
How to test THC & CBD (cannabis) ? Instructions how to use the CBD & THC Test Kit with Cannabis reagent test.

What test kit do I need to test THC (cannabis)?

Semi-quantativeCBD & THC Test Kit
QualitativeCannabis reagent

How can I test THC & CBD (cannabis)?

BEFORE using a CBD & THC reagent test kit

  • It’s RECOMMENDED to use the test under strong light, like daylight.
  • Steps 1-4 are required only for testing amount of THC / CBD, not PRESENCE

(1) STEP ONE for testing THC / CBD flowers / extracts / foods

  • Prepare:
    • good scale
    • representative sample 
    • Cannabis reagent
    • Solvent fluid
    • Glass Vial
    • Plastic Bottle
    • 1 Pipette
    • 1 plastic Test Vial
  • Weigh. Inside a Glass Vial weigh 100 mg (uncrushed plant material) or 40 mg (extracts). Do not close the Glass Vial.

(2) STEP TWO: heating (decarboxylation)

  • Pre heat an oven to 110 °C. Put the open Glass Vial with weighted sample onto a middle rack in the oven. Remove after 60 minutes (30 if using a vacuum oven).

(3) STEP THREE: dissolving

  • Crush herbal sample in Glass Vial with a clean tool, e.g. a toothpick.
  • Use clean pipette to add 4 ml of the Solvent. Close the Glass Vial lid and shake well. Wait 2 minutes.

(4) STEP FOUR: diluting

  • Using pipette add Solvent into a Plastic Dropper Bottle (1,5 ml for herbs or 3,5 ml for extracts).
  • Next with the same pipette add 0,5 ml of the dissolved sample from Glass Vial. to Plastic Bottle.
  • Close the Plastic Bottle firmly, so that the dropper from inside the cap secures itself in place.

(5) STEP FIVE: test it!

  • Open reagents Cannabis A and B and put caps down so they don’t mix.
  • Squeeze 1 drop out of Plastic Bottle into a Test Vial. Add 5 drops of Cannabis Aimmiedietly followed by 5 drops of Cannabis Reagent B. Close the Test Tube and shake briefly.
  • Check results after 60 minutes. Observe test results from a side, with Test Tube half-standing on a white flat surface.
  • Extracts’ results should be multiplied by 5, e.g. 8% means around 40%.
Color Change Results
How to test THC / CBD? Color change results under daylight (top), photographic light (bottom left) and phone camera flash light (bottom right). The deeper the shade of blue, the bigger the amount of THC. Green and yellow hues mean proportionally smaller potency.

AFTER using the CBD & THC Test Kit

  • Wash used accessories first with a solvent and next under running water.


  • Cannabis B. It is important to immiedietly add 5 drops of Cannabis reagent B and shake after adding 5 drops of Cannabis reagent A.
  • No reaction. If your sample does not react, that indicates no presence of THC or CBD, or an error while performing the test. Did you add 5 drops of reagent B immiedietly after 5 drops of A?
  • Color change. Observe results in daylight, from a side, with Test Tubes half-standing on flat white surface. Try to compare samples with each other.
  • How many tests can you get from one test kit? The basic CBD & THC test kit comes with enough Solvent for 14 tests and enough reagents for up to 40 (with additional Solvent). Each one test equals 5 drops of reagents Cannabis A and B each, and 6 ml of Solvent fluid (8 ml for extracts).

CBD / THC Test Results Spectrum

CBD / THC Color Change
BLUE10-20% THC

CBD & THC test did not react as indicated? Watch out!
All test results are available in our instructions.

How to check if reagent for testing THC & CBD works?

  • Test legal hemp and compare color reactions with instructions.
  • Keep a sample to compare later in case of doubt. If control sample reacts fine, it means the reagent still works.

SIN THC potency test was calibrated using reference standards and TLC:

Reagent Test Kit Calibration with Alpha-CAT TLC set
SIN CBD & THC test kit was calibrated with Alpha-CAT test. For thin-layer chromatography tests results must be multiplied by two. Ratios of different samples are consistent between the tests.

Looking where to buy a different reagent test?

How to detect fentanyl?

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.

STEP ONE for testing fentanyl powder / pills / spice

  • 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 blue 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.

How to use a fentanyl test strip?

  • 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 TestDrugs apps.


  • Faint line. Even faint second line result is enough to rule out the presence of fentanyl.
  • Injecting. If you inject you especially need to test each and every dose. It’s best to test the spoon (or cooker) residue every time before use.
  • Speed of the reaction does not indicate quantity nor purity. However, if you are having trouble interpreting your result try using a bigger sample or crushing it better before testing.
  • How many tests can you get from one test kit? A single fentanyl test strip is enough for one test.

Looking where to buy a test kit for fentanyl?

List of all SIN 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 THC & CBD?
How to test FENTANTYL?
How to test COCAINE?
How to test MESCALINE?
How to test KETAMINE?
How to test MEPHEDRONE?
How to test AMPHETAMINE?
How to test HEROIN & OPIOIDS?
How to test an UNKOWN substance or RCs?

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. Remember to avoid mixing with other drugs, take care of yourself and take breaks. Ketamine can be habit forming and is known to cause bladder damage in those cases, therefore regular use can be particularly dangerous. Learn more at