THCA

THCa (tetrahydrocannabinolic acid) is the acid-form precursor to THC that exists in raw, unheated cannabis flower. Chemically THCa has the formula C₂₂H₃₀O₄. It is non-psychoactive in its raw state — chewing raw cannabis flower won't produce a high. When heat is applied (smoking, vaping, dabbing, baking at 230°F+), THCa loses its carboxyl group in a process called decarboxylation, becoming Δ9 THC (C₂₁H₃₀O₂) and releasing CO₂. The conversion is approximately 87.7% efficient by mass — meaning a plant with 27% THCa yields about 23.7% Δ9 THC after full decarboxylation. The 2018 Farm Bill defined legal hemp as cannabis containing less than 0.3% Δ9 THC by dry weight without counting THCa toward that threshold — enabling the entire hemp-derived THCa flower category. Section 781 of P.L. 119-37 closes this gap effective November 12, 2026 by redefining the threshold as total THC rather than just Δ9.