Decarboxylation: Why THCA and CBDA Change With Heat

The short version

Cannabis plants make many cannabinoids first as acids, such as THCA and CBDA. Under some conditions these acids change into the neutral forms THC and CBD. That change is called decarboxylation. This page explains the idea and why it shows up on lab reports. It gives no temperatures, times, equipment settings or preparation steps, and it is not a guide to making edibles or any other product.

Chemistry overview only. Where a source describes how much converts, it varies. See Decarboxylation explained.

What decarboxylation is

A review of the chemistry says acidic cannabinoids can undergo a common organic chemistry reaction called decarboxylation, which turns them into structurally similar neutral cannabinoids with far different pharmacology. [1] The WHO review of CBD likewise describes THC and CBD as generated from THCA and CBDA by nonenzymatic decarboxylation, meaning the change does not need a plant enzyme. [2]

A 2026 review names four acidic cannabinoids: THCA, CBDA, CBGA and CBCA. [3] Pages on the individual compounds: THCA, CBDA, CBGA.

What speeds it up or slows it down

Researchers who studied hemp seed oil report that decomposition of cannabinoid acids generally occurs with light, air and heat. [4] A review notes the change can be promoted or prevented during harvesting or storage, which matters to producers. [1] So the balance of acid and neutral forms in a product can depend on how it has been handled and stored.

Why it matters for lab reports and labels

Lab methods differ in how they handle acids.

• Some gas-chromatography methods use high heat in the instrument, which converts acids to neutral forms during testing. One study found a method without special preparation converted only about 50 to 60 percent of the acids it was given, so total THC and CBD can be underestimated if the method is not chosen carefully. [5]
• Liquid chromatography, and gas chromatography with an added preparation step, can detect acids and neutral forms. [5]
• A "total THC" figure that counts acid and neutral forms together is explained on Total THC and Total CBD and THC vs THCA on a Label.

Because methods differ, a printed percentage is not a universal number. Reported values should always be read together with the lab, method and batch. See How to Read a Cannabis COA.

What is known about the acids themselves

Evidence label: preclinical (cells/animals only) for most claims, with insufficient evidence in people.

• The 2026 review reports that acidic cannabinoids show activities that differ from their neutral counterparts in laboratory studies, but chemical instability, low bioavailability and a dearth of controlled human trials impede clinical translation. [3]
• The same review says acids are not intoxicating like THC, but that this distinction applies primarily to non-heated consumption. [3]
• A human laboratory study of a hemp-derived oral product with roughly equal amounts of CBD and CBDA and of THC and THCA found the acid forms were absorbed faster and reached higher blood levels than the neutral forms. [6] The same study reported that its highest study amount produced subjective intoxication and impaired working memory, so the presence of acids did not make the product harmless. [6]

"Raw cannabis" claims

Marketing sometimes presents raw or unheated cannabis, or a "THCA" product, as a special category. Treat these as marketing claims unless a study supports the exact product. Proper evidence not found, in the sources read, that raw cannabis products have established health benefits. Legal questions about THCA are separate: see THCA Marketing Claims and Legal Questions. This is not legal advice.

Safety note

Do not assume a "THCA" or "raw" label means a product cannot affect you. Heat, light and air can change what is in a product. [4] Children and pets can be harmed by any cannabis product. In the US, call 911 or Poison Help at 1-800-222-1222 in an emergency.