# Decarboxylation

> Decarboxylation is the loss of a carboxyl group as CO2 that turns acid cannabinoids such as THCA and CBDA into neutral THC and CBD, quickly with heat, slowly with time.

- Canonical: https://genetixbay.com/knowledge/glossary/decarboxylation.html
- Also written: decarb, decarbing, decarboxylate, decarboxylated, decarbed
- Glossary category: Cannabinoids and terpenes · Evidence: Established
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

Decarboxylation is a chemical reaction in which a carboxylic acid group (-COOH) leaves a molecule as carbon dioxide. In cannabis it converts the [acid cannabinoids](https://genetixbay.com/knowledge/glossary/acid-vs-neutral-cannabinoids.md) the plant makes ([THCA](https://genetixbay.com/knowledge/glossary/thca.md), [CBDA](https://genetixbay.com/knowledge/glossary/cbda.md), CBGA and others) into their neutral counterparts ([THC](https://genetixbay.com/knowledge/glossary/thc.md), [CBD](https://genetixbay.com/knowledge/glossary/cbd.md), [CBG](https://genetixbay.com/knowledge/glossary/cbg.md)). The reaction is driven mainly by heat; it also happens slowly at room temperature during drying, curing and storage.

## In practice

Smoking and vaporising decarboxylate THCA almost instantly. Raw, cured flower is still mostly THCA, which is why a COA shows THCA high and Δ9-THC low. Over long storage, slow decarboxylation raises the Δ9-THC line a little while oxidation pushes some THC on toward [CBN](https://genetixbay.com/knowledge/glossary/cbn.md). Gas chromatography decarboxylates samples in its hot inlet, which is why GC cannot measure the acids directly. GenetixBay doesn't publish processing temperatures or times.

## Units and formula

Mass is lost as CO2: 1 g THCA gives at most [0.877](https://genetixbay.com/knowledge/glossary/total-thc.md) g THC; 1 g CBDA gives at most 0.877 g CBD. Real conversions fall short of that because of side reactions and degradation.

## Don't confuse with

- **Oxidation**: a different reaction that degrades THC to CBN.
- **Curing**: a controlled moisture decline; any decarboxylation during it is minor.

## Related terms

[THCA](https://genetixbay.com/knowledge/glossary/thca.md), [THC](https://genetixbay.com/knowledge/glossary/thc.md), [Acid vs neutral cannabinoids](https://genetixbay.com/knowledge/glossary/acid-vs-neutral-cannabinoids.md), [Total THC](https://genetixbay.com/knowledge/glossary/total-thc.md), [Gas chromatography](https://genetixbay.com/knowledge/glossary/gas-chromatography.md)

## Read more

- [Long-term storage: keeping cured flower potent and aromatic](https://genetixbay.com/knowledge/harvest-cure/long-term-storage.md)

## Sources

1. Wang M, Wang YH, Avula B, et al. 2016. Decarboxylation study of acidic cannabinoids: a novel approach using ultra-high-performance supercritical fluid chromatography/photodiode array-mass spectrometry. Cannabis and Cannabinoid Research 1(1):262-271.
2. ElSohly MA, Slade D. 2005. Chemical constituents of marijuana: the complex mixture of natural cannabinoids. Life Sciences 78(5):539-548.