Most of what goes wrong with cannabis and CBD products is something added rather than something missing. CBD flower and extracts get sprayed with a synthetic cannabinoid, a full agonist at the receptor where THC is only partial, so a product that is accurately labelled as CBD can still carry one.
The 4-AP reagent answers the question that matters first: whether the sample holds a real cannabinoid at all. THC and CBD react with it and the synthetics do not, so plant material that gives no colour is itself the finding. Across 187 lab-tested samples, 78% contained a second compound, mostly other cannabinoids rather than adulterants: CBD in 90, delta-8-THC in 38, CBN in 52 and CBG in 41, with the synthetic MDMB-PINACA in 11.
The table below counts what the labs found, by compound.
What labs detected in cannabis and CBD products, by number of samples
MDMB-PINACA in 11 samples is a synthetic cannabinoid, a full agonist at the CB1 receptor where THC is only partial, and it is the reason to test a product you bought legally as well as one you did not. We looked at that market separately, including samples where an accurately labelled CBD flower carried a synthetic sprayed on top.
Delta-8-THC, HHC, THCP and the rest are cannabinoids and they do react with the 4-AP reagent, unlike the synthetics, so the reagent will not separate them from delta-9-THC for you. What separates them is a testing card: TLC shows each cannabinoid as its own spot at its own height, which is how a sample sold as high-THC flower turns out to be mostly CBD and CBN, or how delta-8 shows up in a product sold as delta-9.
THC and CBD with the 4-AP reagentCBD and THC separated on a TLC testing card
The reagent answers whether a cannabinoid is present at all, which is the synthetic question. The testing card answers which cannabinoids and how much, which is the quantity and the delta-8 question. For flower, hash, oil or vape liquid the sample preparation differs but the testing card is the same.
No. It indicates that a cannabinoid is present. Content needs a TLC testing card against a reference.
Will it tell delta-8 from delta-9?
No. Both are cannabinoids and both react. A testing card separates them.
Why is CBN in so many samples?
CBN forms as THC degrades, so a high CBN reading generally indicates age or poor storage.
Can I test vape liquid?
Yes, on a dried drop. The synthetic cannabinoid samples with nicotine in them came from vapes.
No test result can tell you a substance is safe. No substance is 100% safe.This article is published for harm reduction purposes. It does not encourage the use of psychoactive substances and does not replace medical advice.
