PrEP reaches its maximum effectiveness after about 7 days of daily use for receptive anal sex. For other types of exposure, including vaginal sex, it may take up to 20 days.
How soon does PrEP start working?
Aug 2024 
Aug 2024 PrEP reaches its maximum effectiveness after about 7 days of daily use for receptive anal sex. For other types of exposure, including vaginal sex, it may take up to 20 days.
