# CBL

> CBL (cannabicyclol) is a minor cannabinoid formed when CBC is exposed to light; it is a degradation product rather than something the plant makes by enzyme.

- Canonical: https://genetixbay.com/knowledge/glossary/cbl.html
- Also written: cannabicyclol, CBLA, cannabicyclolic acid
- 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"

CBL, cannabicyclol, is a non-enzymatic degradation product. UV and visible light drive an internal ring-closing reaction in [CBC](https://genetixbay.com/knowledge/glossary/cbc.md) (or [CBCA](https://genetixbay.com/knowledge/glossary/cbca.md), giving CBLA), converting it to CBL. It is usually found only at trace levels and mainly in aged or light-exposed material. It was first described in the 1960s and its structure was revised shortly after.

## In practice

Most potency panels don't report CBL at all. When it does appear, it tells you about storage history, much as [CBN](https://genetixbay.com/knowledge/glossary/cbn.md) does: material kept in clear containers or bright conditions. For growers, the practical point is the same as for every [cannabinoid](https://genetixbay.com/knowledge/glossary/cannabinoid.md) and [terpene](https://genetixbay.com/knowledge/glossary/terpene.md): store [cured](https://genetixbay.com/knowledge/glossary/curing.md) flower cool, dark and with minimal air. No meaningful effects are reported for CBL at the levels found in flower.

## Don't confuse with

- **CBC**: the parent compound that light converts into CBL.
- **CBN**: also a degradation product, but from [THC](https://genetixbay.com/knowledge/glossary/thc.md) by oxidation.
- **CBG**: a precursor-derived cannabinoid with a similar abbreviation.

## Related terms

[CBC](https://genetixbay.com/knowledge/glossary/cbc.md), [CBCA](https://genetixbay.com/knowledge/glossary/cbca.md), [CBN](https://genetixbay.com/knowledge/glossary/cbn.md), [Cannabinoid](https://genetixbay.com/knowledge/glossary/cannabinoid.md)

## Read more

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

## Sources

1. Hanuš LO, Meyer SM, Muñoz E, Taglialatela-Scafati O, Appendino G. 2016. Phytocannabinoids: a unified critical inventory. Natural Product Reports 33(12):1357-1392.
2. ElSohly MA, Slade D. 2005. Chemical constituents of marijuana: the complex mixture of natural cannabinoids. Life Sciences 78(5):539-548.