PrEP FAQ: the questions everyone asks, answered

Taken as prescribed, PrEP lowers the risk of getting HIV from sex by about 99% and from injection drug use by at least 74%. Missing doses lowers protection. More in PrEP 101.

On daily pills, about 7 days for anal sex and 20 days for vaginal sex. Injections protect on schedule. Use condoms until protected — see time to protection.

Yes — it's prescription-only with a negative HIV test first and follow-up every 2–3 months. See how to get PrEP.

PrEP is ongoing, taken before exposure; PEP is emergency medicine started within 72 hours after a possible exposure. Full breakdown: PrEP vs PEP.

It's highly effective when taken as prescribed; rare failures are almost always from missed doses or strong enzyme-inducing drugs. Check yours in the interaction checker.

Most people have none or mild, short-lived nausea/headache/tiredness that settle within a month. Truvada needs kidney/bone monitoring; Descovy is gentler. Use our symptom body-map to tell expected from concerning.

Yes — no chemical interaction. The only risk is heavy drinking leading to missed doses, so keep a routine.

Descovy (TAF) is associated with a small gain (~1–3 kg); Truvada is weight-neutral. See Truvada vs Descovy.

No significant interaction with gender-affirming hormones or contraception, and it doesn't reduce contraceptive effectiveness. Details for trans people and women.

Yes — recommended in pregnancy and breastfeeding if at ongoing risk; Truvada has the most data. See the women's guide.

Usually $0 with insurance or Medicaid in the US (including visits/labs). Generic Truvada is cheap; uninsured people can get it free via programs like Ready, Set, PrEP. See cost & coverage.

Yes — assistance programs and generics make it low- or no-cost. A PrEP navigator can find the cheapest path.

Anyone HIV-negative who could benefit — all genders, no age limit. Not sure? Try our 2-minute check.

Yes — Truvada, Apretude and lenacapavir are approved for vaginal exposure (not Descovy or 2-1-1). See PrEP for women.

No — only HIV. Use condoms, test regularly, and ask about Doxy-PEP.

Take it when you remember; 4+ doses/week protects for anal sex, near-daily for vaginal. See missed-dose guidance.

2 pills 2–24 h before sex, then 1 at 24 h and 1 at 48 h — for anal sex in men only, not FDA-approved in the US, not for vaginal sex. See the MSM guide.

Yes — Apretude every 2 months and lenacapavir twice a year. Compare on the options page.

It depends on your body, exposure and preferences. Start with the comparison or the self-check.