Health Advice



Beyond CBD: Here come the other cannabinoids, but where’s the evidence?

Peter Grinspoon, Harvard Health Blog on

Published in Health & Fitness

The cannabinoid CBN, or cannabinol, is present in trace amounts in the cannabis plant, but is mainly a byproduct of the degradation of THC. Marijuana that has been sitting around for too long has a reputation for becoming “sleepy old marijuana” — purportedly because of higher CBN concentrations in it, though there are other plausible explanations for this phenomenon. CBN is widely marketed for its sedative and sleep-inducing qualities, but if you review the literature, it is interesting to note that there is virtually no scientific evidence that CBN makes you sleepy, except for one study of rats that were already on barbiturates, and who slept longer when CBN was added. This isn’t to say that CBN doesn’t make people sleepy — as many people claim — just that it hasn’t been scientifically established yet.

Usually with claims about cannabinoids, there is some evidence, at least in animal studies, to back them. CBN does, however, have potential (though only in animal studies so far) to act as an appetite stimulant and an anti-inflammatory agent — both extremely important medical uses, if they pan out in humans. One recent study from Israel in humans demonstrated that strains of cannabis higher in CBN were associated with better symptom control of ADHD. We need more human studies before marketing claims about the benefits of CBN are supported by science.


Delta-8-THC is found in trace quantities in cannabis, but can be distilled and synthesized from hemp. It is increasingly being marketed as medical marijuana with less of the high and less of the anxiety that can come with this high. Unlike the other compounds discussed here, Delta-8-THC is an intoxicating cannabinoid, but it has only a fraction of the high that THC causes — and much less of the accompanying anxiety and paranoia. It can alleviate many of the same symptoms that cannabis can, making it a potentially attractive medicine for people who want little to do with the high of cannabis. It is thought to be especially helpful for nausea and appetite stimulation. There is some evidence (albeit from a very small study of 10 children) that suggests delta-8-THC may be an effective option to prevent vomiting during chemotherapy treatments for cancer. While the claims for delta-8 are intriguing, there is a lack of good human studies to substantiate its efficacy or safety, so we need to take the marketing claims with a grain of salt.

There is renewed interest in cannabis research


As acceptance of medical cannabis is growing — currently, 94% of Americans support legal access to medical cannabis — the one thing that virtually everyone agrees on is the need for further research into cannabis and cannabinoids: their benefits, their harms, and the ways we can develop and safely use them to improve human health. We are in the midst of an incredibly exciting time, with new discoveries occurring daily in cannabinoid science, and I am eager to see what the future holds. However, just as we’ve learned from our experiences with CBD, we need to be patient and filter our enthusiasm through the calm lens of science. Most of all, we need to be smart consumers who can find the true benefits amidst the complexity of political agendas and marketing claims that seem to accompany all things related to cannabis.

(Peter Grinspoon, M.D., is a contributor to Harvard Health Publications.)

©2021 Harvard University. For terms of use, please see Distributed by Tribune Content Agency, LLC.