PrEP: medication to prevent HIV

What PrEP is

PrEP (pre-exposure prophylaxis) is medication for people who do not have HIV, taken to lower the chance of getting it. When taken as prescribed, PrEP reduces the risk of getting HIV from sex by about 99% and from injection drug use by at least 74%.

PrEP protects against HIV only. It does not prevent other sexually transmitted infections, so regular STI testing and condoms still matter.

PrEP options

• Daily pill (emtricitabine/tenofovir disoproxil fumarate, including generics): for people at risk through sex or injection drug use.
• Daily pill (emtricitabine/tenofovir alafenamide): for people at risk through sex, except people assigned female at birth who are at risk through receptive vaginal sex.
• Injection every 2 months (cabotegravir), given by a provider after starting doses.
• Injection every 6 months (lenacapavir), approved by the FDA in 2025, given by a provider after starting doses.

Your provider will help you choose based on your health, how you might be exposed, and what fits your routine.

When PrEP starts protecting you

Daily PrEP pills reach maximum protection after about 7 days for receptive anal sex, and after about 21 days for receptive vaginal sex and injection drug use. Until then, use other prevention methods.

What to expect while on PrEP

• An HIV test before you start, and regular HIV tests while you take PrEP.
• Checkups that may include STI testing and, for pills, kidney function tests.
• Side effects such as nausea or headache can happen early on and usually ease over time. Tell your care team about anything that bothers you.
• Do not stop or restart PrEP on your own. Talk with your provider first so you stay protected.