PEP, PrEP, and DoxyPEP: What they are and how they work

When it comes to protecting yourself against HIV and other sexually transmitted infections (STIs), there are a lot of different options. Condoms, both external and internal, are the most well-known, but other prevention tools—namely, PrEP, PEP, and DoxyPEP—can also help lower your risk of infection.

If you’ve heard these acronyms before but aren’t sure what they mean, here’s a quick overview of what they are, how they work, and how to access them.

What’s PrEP?

PrEP stands for pre-exposure prophylaxis. It’s a prescription medication you take regularly to lower the possibility of getting HIV. Think of it like birth control for HIV—it helps protect you in an ongoing way.

PrEP comes in two forms:

• Daily pills (like Truvada or Descovy)
• A long-acting shot you get every two months (Apretude)

PrEP can lower the risk of getting HIV from sex by about 99%. It also protects people who use injection drugs.

Deciding to start on PrEP is a personal decision, but some people choose to take it because they:

• Have a partner who is HIV-positive
• Have sex without condoms
• Don’t know the HIV status of their partners
• Share needles
• Have had other STIs previously

It’s important to get tested for HIV before starting PrEP, and then see your provider for follow-up visits every few months.

What’s PEP?

PEP stands for post-exposure prophylaxis. It’s a medication you take after a possible exposure to HIV.

Timing is everything: PEP must be started within 72 hours (three days) after the possible exposure. The sooner you start, the more effective it is.

People may decide to take PEP because:

• A condom broke during sex, and they’re unsure about their partner’s HIV status
• They shared needles
• They experienced sexual assault

PEP is a prescription medicine you take for 28 days. You can get it through a health care provider or at an emergency room.

PEP is often paid for by health insurance, but if you don’t have insurance or your insurance doesn’t cover it, ask your provider about ways to get discounted medication.

What’s DoxyPEP?

DoxyPEP stands for doxycycline post-exposure prophylaxis. It’s the newest addition to the STI prevention toolkit and can help prevent some bacterial STIs, like chlamydia, gonorrhea, and syphilis. Some people call DoxyPep the emergency contraception of STIs.

Here’s how it works: After sex without a condom (or if the condom breaks), you take a single dose of the antibiotic doxycycline (usually 200 mg) within 72 hours. Research has shown that DoxyPEP can significantly reduce the risk of getting bacterial STIs, especially for folks at higher risk, including men who have sex with men (MSM) and transgender women. It is also often prescribed alongside PEP to help prevent infections after sexual assault.

DoxyPEP isn’t for everyone yet—it’s still being studied, and your provider can help decide if it’s right for you. It’s important to use it only as prescribed to help prevent antibiotic resistance.

PrEP vs. PEP vs. DoxyPEP: What’s the Difference?

PrEP

When to take it: Daily (pills) or every two months (injection).

Purpose: Ongoing HIV prevention.

How to get it: Prescription from a provider.

PEP

When to take it: Immediately after possible exposure (within 72 hours).

Purpose: HIV prevention after sex or needle sharing.

How to get it: Provider or ER visit.

DoxyPEP

When to take it: Immediately after possible exposure (within 72 hours).

Purpose: Bacterial STI (chlamydia, gonorrhea, syphilis) prevention after sex.

How to get it: Provider or ER visit.

More tips for preventing HIV and STIs

There’s no one-size-fits-all approach to HIV and STI protection—but there are lots of options. PrEP, PEP, and DoxyPEP can be great options for some people, and using condoms, getting regular STI testing, and having open conversations with your partners are all important too.

If you’re interested in these medications or in speaking with a health care provider about the best infection prevention method for you, search for a health center in your area. And remember: Whatever approach you take, it’s about taking charge of your health and your future.