How Quickly Does PrEP Start Working?

To reach maximal needed prep concentration in the rectal tissue it takes 7 days.

To reach maximal needed prep concentration in the vaginal tissue it takes 21 days.

To reach maximal needed prep concentrations in the blood it takes 21 days.

There Is no research regarding the concentrations in the tissue of the penis. Therefore, we recommend you to take PrEP for at least 3 weeks before sex.