That last question can’t be reliably answered—the research just isn’t there yet. But the knowledge gap hasn’t done much to dampen consumer interest in CBD, and manufacturers looking for the next big thing have already started experimenting with lesser-known cannabinoids like cannabinol, or CBN. Cannabinoids are a salesman’s dream: When little is known, virtually anything can be passed off as possible.
Until CBD’s ascendance, tetrahydrocannabinol, or THC—the chemical in weed centrally responsible for making people feel high—was the most famous of the cannabinoids. Higher concentrations of THC are what mark the legal distinction between cannabis and hemp, which are virtually identical in most other ways. After a years-long pilot program, growing industrial hemp became legal nationwide at the end of 2018. Most cannabinoids can be extracted from hemp, which means that the U.S. currently has a ready supply of the chemicals for the first time in its history.
Regulations on the manufacture and sale of cannabinoids haven’t kept up with their newly widespread availability. Hemp might be legal, but the Food and Drug Administration has so far not issued any guidance on how CBD—by far the most widely available cannabinoid—should be quality-tested or labeled, what claims can be made about its use, or who can sell it. In the agency’s view, CBD is still illegal to market as a dietary supplement, even though one of the plants from which it is derived is legal to grow and the substance is sold widely and in a variety of forms. The FDA also says it’s illegal to sell as an additive in foods, even though those, too, are widely available, including CBD sodas and gummy bears. For the FDA to make more nuanced rules, it would likely need to reverse its stance on CBD’s legality as a supplement.
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To be fair, the FDA does not have much hard evidence on which to make more detailed regulations. Academic research on cannabis and its derivatives has long been restricted, and funding to study cannabis derivatives can be difficult for scientists to secure. Legal hemp cultivation will aid those studying the therapeutic value of the cannabinoids, but clinical trials to establish effects and dosages take years. Earlier this year, Esther Blessing, a researcher at New York University Langone Health currently studying CBD’s effects on anxiety, told me she thought the chemical held significant promise, but that it would take a decade to gather enough information for FDA approval as a drug with standardized dosages and predictable outcomes. She cautioned that currently, it’s impossible for most consumers to know whether what they’re buying has any CBD in it at all, let alone evaluate its quality.
What’s currently known about cannabinoids is preliminary. A 1976 review suggests that CBN has potential as a mild sedative in conjunction with THC, and a 2002 study looked at its pain-relieving properties. CBD, in doses much higher than are commonly available in consumer products, seems to alleviate anxiety under experimental conditions. In 2017, the National Academies of Sciences, Engineering, and Medicine issued a research review that found substantial or conclusive evidence that cannabis or cannabinoids are effective in the treatment of chronic pain, chemotherapy-induced nausea, and some symptoms of multiple sclerosis. The report also recommended that more detailed research be done to address gaps in the evidence, and that better guidelines for evaluating cannabis research be developed. What’s known about the dozens of cannabinoids beyond THC, CBD, and CBN is even more limited.