1. What is the “THC Max” that appears on the lab report? Shouldn’t it just be the sum the THC and the THCA?:
“THC Max” is the maximum amount of THC that could be obtained from the sample if all of the THCA were converted to THC.
THC Max = (all of the THC) + (87.7% of the THCA)
Where does that 87.7% come from? Why can’t we just add the two numbers together?
To convert THCA to THC (the psychoactive cannabinoid), it’s necessary to heat the THCA. But this process (sometimes called activation, or decarboxylation if you’re a chemist) means that the THCA molecule loses a molecule of CO2, carbon dioxide. That molecule of CO2 was 12.3% of the weight of the THCA molecule. Here’s an example:
1000 mg THCA + heat → 877 mg THC + 123 mg CO2
By the way, exactly the same relationship applies to CBD, CBDA, and “CBD Max”.
2. How big of a sample do I need to submit to the lab for testing?
Flower: 1 gram
Concentrates (shatter, wax, hash, kief, oil, etc): 500 milligrams
Edibles: 1 serving
Lotions, potions, topicals, tinctures, etc: 1 gram or 1 milliliter (minimum)