Like any drugs, there may be some side effects when starting PrEP. A small number of people experience mild side-effects when they start taking PrEP, such as headaches and upset stomachs. But these usually only last for a couple of weeks. And many people get no side-effects at all. If you do experience any of these mild side-effects when starting PrEP, it can help to take your PrEP with or just after food. Have a chat to your doctor if you’re worried about any side-effects or if they persist.

A very small number of people may experience significant changes to their kidney function and problems with their bone density if their bones are not already strong before starting PrEP. These side-effects usually occur in people with pre-existing or other medical conditions, but your doctor will check these before you start PrEP and monitor them regularly just to be sure.