McGuire doesn’t advise buying CBD products. You need to differentiate, he says, between the extremely high doses of pharmaceutical-grade pure CBD that participants in the handful of successful studies were given and the dietary supplements available over the counter or online. “These may contain quite small amounts of CBD that might not have large enough concentrations to have any effects,” he says. “It’s the difference between a nutraceutical and a pharmaceutical.” These supplements aren’t allowed to make claims of any effects. “If you’re making creams or sports drinks with CBD, you can say anything you like as long as you don’t say it will do such and such,” he says.
Preliminary research indicates that cannabidiol may reduce adverse effects of THC, particularly those causing intoxication and sedation, but only at high doses. Safety studies of cannabidiol showed it is well-tolerated, but may cause tiredness, diarrhea, or changes in appetite as common adverse effects. Epidiolex documentation lists sleepiness, insomnia and poor quality sleep, decreased appetite, diarrhea, and fatigue.
One of the strongest nutraceutical CBD oils is called Charlotte’s Web, with a 50mg dose. Charlotte’s Web is produced in Colorado by the Stanley Brothers, and named after Charlotte Figi, a girl who became famous in the US after her frequent seizures, brought on by the rare Dravet syndrome, were greatly reduced when she started taking CBD oil aged five. The company makes THC products too and is extremely successful, having just offered shares on the Canadian securities exchange, raising about $100m.