Last month the UK’s Food Standards Authority slashed the recommended safe daily intake of cannabidiol (CBD) from 70mg to 10mg. An estimated one in 10 people in the UK have used products containing CBD, and many users believe it can help with ailments such as insomnia, anxiety and pain. But is there any evidence for the supposed benefits, and what’s behind the FSA’s decision? Ian Sample talks to Dr Will Lawn of Kings College University, who has studied the health effects of CBD, to find out. Help support our independent journalism at theguardian.com/sciencepod