CBN, cannabinol, is a cannabinoid that the plant does not make by enzyme. It forms mainly when THC (or THCA, which yields CBNA) oxidises and aromatises, a reaction driven by oxygen, heat, light and time. That is why CBN is the classic marker of old or poorly stored cannabis and of old hashish.
In practice
Fresh, well-cured flower usually shows CBN under 0.2% w/w or not detected. Material stored warm, in light or with lots of air for months shows rising CBN and falling THC. A high CBN line on a COA is a storage story, not a cultivar trait.
Don't confuse with
- CBD: unrelated in origin; CBN comes from THC.
- Amber trichomes: a visual change in the head, not a measurement of CBN.
Myth check
House position: the idea that letting trichomes go amber on the plant fills the bud with CBN and produces "couch-lock" is unsupported. CBN is mainly a post-harvest oxidation product; amber colour on the plant does not mean meaningful CBN. Harvest timing is a matter of preference: a few clear, mostly cloudy, some amber. See trichome ripeness and Mythbusters.
A cannabinoid is any compound that binds the body's cannabinoid receptors or shares the typical cannabis terpenophenolic structure; the plant-made ones are phytocannabinoids such as THCA and CBDA.THC (Δ9-tetrahydrocannabinol) is the neutral, decarboxylated cannabinoid mainly responsible for cannabis's reported intoxicating effects; the living plant makes it almost entirely as THCA.THCA (tetrahydrocannabinolic acid) is the acid cannabinoid that drug-type cannabis makes in its trichomes; heat or time decarboxylates it into THC, losing about 12% of its mass.Hashish is the traditional pressed resin concentrate of cannabis, made for centuries by sieving or rubbing trichome heads from plants and compressing them into blocks or balls.A COA (certificate of analysis) is a lab's signed report of what it measured in a specific sample, such as cannabinoids, terpenes, moisture and contaminants, with methods and limits.The maturity of glandular trichome heads, read by colour under magnification: clear (immature), cloudy or milky (mature), then amber (ageing).A hair-like outgrowth of the plant's skin; in cannabis the glandular types make and store the resin holding cannabinoids and terpenes.The span of days, often one to two weeks, in which a cannabis plant is ripe enough to cut, judged mainly by trichome head colour and bud development.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.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.
