British food safety regulators have dramatically reduced the recommended daily CBD intake to 10mg, dealing a significant blow to the industry both in the UK and internationally.
The Food Standards Agency (FSA) and Food Standards Scotland have issued "precautionary advice" curtailing CBD consumption following warnings about liver damage and thyroid problems linked to long-term cannabidiol use.
Both regulatory bodies pointed to "new evidence from the industry and updated advice from our independent scientific committee" as the basis for the change.
The previous recommended upper daily limit for healthy adults stood at 70mg.
FSA chief scientific advisor, Professor Robin May, said: "The more CBD you consume over your lifetime, the more likely you are to develop long-term adverse effects, like liver damage or thyroid issues. The level of risk is related to how much you take, in the same way it is with some other potentially harmful products such as alcoholic drinks.
"We encourage consumers to check the CBD content on the product label to monitor their overall daily consumption of CBD and consider if they wish to make changes to how much they take based on this updated advice."
The FSA, which has not called for any products to be pulled from shelves, noted that 10mg is roughly equivalent to four to five drops of 5% CBD oil.
The revised guidance draws on findings from two independent scientific bodies — the Committee on Toxicity and the Advisory Committee on Novel Foods and Processes, the FSA confirmed.
The update follows a review of safety data submitted by CBD companies as part of their novel foods applications to the FSA. Several Australian products are included on a public list of approved CBD products permitted for sale in the UK, though none have yet received formal authorisation.
While the regulator acknowledged there is "no acute safety risk" from exceeding 10mg of CBD daily, evidence points to adverse effects on the liver and thyroid when higher amounts are consumed over an extended period.
FSA chief executive Emily Miles said: "We have always advised the public to think carefully about taking edible CBD products and, as with all foods, we continue to review our advice based on the evidence we gather from industry.
"We understand that this change to our advice will have implications for products currently on the market that contain more than 10mg of CBD per serving. We will be working closely with industry to minimise the risk, to ensure consumers are not exposed to potentially harmful levels of CBD."
The decision is likely to face pushback from industry figures and parts of the scientific community.
In September, a scientific review commissioned by Canopy Group and Charlotte's Web recommended a maximum daily dose of 160mg a day, 10mg above the 150mg ceiling the Therapeutic Goods Administration approved for over-the-counter CBD in Australia.
No products have yet been registered with the TGA for pharmacy sales, with only Bod Science so far able to demonstrate any statistically relevant benefits of CBD — for sleep — over a placebo.
Cannabis Trades Association executive director Marika Graham-Woods was sharply critical of the FSA's decision.
Quoted in The Guardian, she said: "All this does is frighten consumers and retailers and it stops the industry going forward again. I don't see any benefit in what they have done."