How to start and stop PrEP
Starting oral PrEP
Everyone is now recommended to start oral PrEP using a double dose (two pills) for the first dose BEFORE sex.
This gives protection within two hours.
Continuing oral PrEP
Daily dosing then involves continuing with a single pill every day at roughly the same time.
For daily PrEP, current guidelines recommend at least four daily doses a week.
But if you stop PrEP for a week, please restart using a double dose and take seven daily post-sex doses that week.
Stopping oral PrEP
If you are using event-based dosing, continue daily dosing for either another two days (2:1:1 dosing) or seven days (2:7 dosing).
Before stopping daily dosing, please continue for either two or seven days after you last had sex. This depends on how you are dosing PrEP. Please see:
Dosing with TAF vs TD
TAF/FTC can be dosed the same way as TD/FTC.
Even though there is less evidence for vaginal and neovaginal sex, this should still be okay.
This is because PrEP efficacy is no longer thought to be linked to drug levels in different tissues, but to drug levels in cells called PBMCs.
Stopping injectable PrEP
Special advice is needed if you decide to stop injectable PrEP.
This is because of how long these drugs stay in your body. In theory, if for any reason you become HIV positive after stopping PrEP injections, the virus might develop resistance to the PrEP meds.
Changing to oral PrEP if you continue to be at risk of HIV will prevent drug resistance.
This is important to know about even if you are stopping PrEP because you are no longer at risk.
Last updated: 1 November 2025.