CBL
CBC's sunlight-born cousin
Cannabinoid
What is CBL?
CBL (cannabicyclol) is a minor cannabinoid that forms when CBC is exposed to UV light or heat — a photodegradation product rather than something the plant builds directly. It's non-intoxicating and found only in trace amounts.
Effects
CBL was long regarded as inactive — but 2025 changed that. A study in the Journal of Natural Products found CBL has high affinity for the serotonin 5-HT1A receptor and acts as a potent positive allosteric modulator: at low concentrations it dramatically amplified serotonin's own signal, while barely touching the CB1 and CB2 cannabinoid receptors. Given 5-HT1A's role in mood and anxiety, that makes CBL an unexpectedly interesting target for drug discovery.
The first in vivo study
A 2026 study in the Journal of Cannabis Research provided the first in vivo data on CBL. In mice, it reduced LPS-induced paw edema and inflammation and attenuated neuropathic cold allodynia — but only at high doses, and the anti-inflammatory effects appeared to run through adenosine A2A receptors rather than cannabinoid receptors. At those doses it also caused hypothermia and reduced movement, so the therapeutic window is unclear. Early days, but CBL is no longer a complete unknown.
Research note
CBL is a good example of why it's worth checking back on minor cannabinoids — for decades it was treated as an inert trace degradation product, and recent work revealed real biological activity. When it appears on a COA it's still usually a minor line item, but the story keeps evolving.
Conditions that cite this compound
These condition guides point here — they cover the same compound from the patient side.