‘In doses used as a food supplement, CBD poses few risks, and side effects are unusual but can include a dry mouth or drowsiness,’ reveals Dr Brewer. ‘Higher doses used medically are well tolerated, and there are no serious safety concerns. A World Health Organization report issued in 2017 concluded that cannabidiol does not appear to have abuse potential or cause harm.'
Not much, as far as humans are concerned—at least not yet. The vast majority of studies have been on animals, as of yet, and there are few high-quality studies on humans. Even the oil’s effect on pain—something that CBD oil is popularly used for—isn’t proven. “The studies available are small or not well designed,” says Dr. Devinsky. “There’s a lot of religion out there, but not a lot of data.”
CBD oil is most readily available as a tincture. This can be taken by applying a few drops under your tongue, holding in your mouth for a few moments so it can be absorbed, before swallowing. It can also be added to water or smoothies. A spray form is available (simply spritz under your tongue), as are capsules, gummies, creams that can be applied topically, and e-liquid for vape pens.