HIV Guide • PEP vs PrEP
PEP vs PrEP
They sound alike but do different jobs. PEP is emergency protection after a possible exposure. PrEP is ongoing protection before one. Here’s how to tell which you need.
Every order is reviewed by our clinical team before it’s sent.
The Short Answer
PEP and PrEP: What’s the Difference?
They sound alike and they’re easy to mix up, but they do different jobs. The simplest way to hold them apart is timing. PEP is taken after a possible exposure, as an emergency. PrEP is taken before and around the time of possible exposure, as ongoing protection. One is the fire extinguisher, the other is the smoke alarm you live with.
If you may have been exposed in the last 72 hours, PEP is what you need right now, and quickly. You can order PEP here or chat to order. PrEP is the conversation for afterwards, or for anyone whose risk is ongoing.
Side by Side
How They Compare
Both use antiretroviral medicines, medicines that stop HIV from copying itself, but they’re used in opposite situations.
PEP: After Exposure
Started within 72 hours of a specific possible exposure. A one-off 28-day course. Emergency use, when something has already happened.
PrEP: Before Exposure
Taken regularly by people at ongoing higher risk. Protects continuously, before any exposure. Planned, not reactive.
If you keep finding yourself reaching for PEP, that’s usually the sign that PrEP is the better fit. Relying on repeated emergency courses is harder and less protective than steady, planned prevention.
Choosing
Which One Is Right for You?
It comes down to where you are right now. If a possible exposure has already happened within the last 72 hours, the answer is PEP, today. If exposure is a recurring possibility in your life, through a partner whose status is unknown or positive, or other ongoing risk, PrEP is worth a serious look as continuous protection.
Your PrEP Options
- ✓Daily pill: one tablet every day. It reaches full protection after about 7 days for anal sex, and about 21 days for vaginal sex.
- ✓Lenacapavir injection: just two injections a year. Available now, and a good fit if remembering a daily pill is hard.
- ✓CAB-LA injection: one injection every 2 months. Available on request.
- ✓On-demand (2-1-1): pills taken around the time of sex. Only proven for anal sex, so it isn’t suitable for vaginal sex.
Whichever you choose, you’ll need a recent negative HIV test before you start, because PrEP isn’t safe for someone who already has HIV. If you’ve had a flu-like illness in the last few weeks, tell us, so we can rule out a very new infection first. You can use our checker to see if PrEP fits you. If you’ve just finished a course of PEP, our guide to HIV testing after PEP covers what comes next.
Exposed in the Last 72 Hours?
Then this is a PEP moment, not a PrEP one. Start now, and we can talk about ongoing protection afterwards.
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Common Questions
PEP vs PrEP, Answered
What is the difference between PEP and PrEP?
Timing is the key difference. PEP is taken after a possible exposure, as an emergency 28-day course started within 72 hours. PrEP is taken regularly before and around possible exposure, as ongoing protection for people at higher risk.
Should I take PEP or PrEP?
If a possible exposure has already happened within the last 72 hours, you need PEP now. If exposure is an ongoing possibility in your life, PrEP offers continuous protection and may be the better fit.
Can I switch from PEP to PrEP?
Yes. If your risk is ongoing, you can usually start PrEP the day after your last PEP dose, with no gap in protection, as long as an HIV test confirms you are still negative. Our team can guide you through that switch.
Is PrEP a daily tablet?
Not only. PrEP comes as a daily tablet, a lenacapavir injection given twice a year, or a CAB-LA injection every 2 months. On-demand pills are another option, but only for anal sex. Our team can help you choose.
Do PEP and PrEP use the same medicines?
Both use antiretroviral medicines that stop HIV from copying itself, but they are used differently: PEP as a short emergency course after exposure, PrEP as ongoing prevention before exposure.
Right Now, Is It PEP or PrEP?
If you may have been exposed in the last 72 hours, it’s PEP, and time matters. Start now, and we can talk about ongoing protection with PrEP afterwards.