Guides

PrEP and side effects

The majority of people taking PrEP do not get side effects. 

However, like all other medicines, PrEP has the potential to cause side effects. In studies, mild nausea, diarrhoea, bloating and headache were reported in the first month by less than 1 in 10 people. These side effects then usually stop.

Occasionally, PrEP can cause more serious side effects that reduce kidney function and/or bone health. This is why kidney tests are run before and during treatment. 

It might also be important if you are younger than 30 as your bones are still developing.

So far there have not been any reports of bone fractures related to PrEP use.

Event based PrEP might reduce the risk of these side effects, though this has not been formally studied yet.

Last updated: 1 November 2019.