Cannabinoids
THC and THCA
Related names, different compounds.
Last reviewed: 2026-09-14
The basics
THCA is a cannabinoid acid and a precursor of THC. Decarboxylation can convert THCA into THC. They are not the same molecule: the reaction changes the molecular composition.
What the evidence means
A label may distinguish measured THC from THCA or show a calculated total. Read the report’s definitions before comparing numbers. A potential total is not a guarantee of the amount someone will absorb.
A useful question
Is this number measured THC, THCA, or a calculated total?
Sources and further reading
Use the sources to check the scope of each claim. A chemical measurement, a laboratory experiment and a study in people answer different questions.