What is Doxy-PEP?
Doxy-PEP (short for doxycycline post-exposure prophylaxis) means taking 200mg of doxycycline within 72 hours after sex to help stop certain bacterial STIs before they take hold.
How Well Does It Work?
Clinical studies show Doxy-PEP can reduce:
- Syphilis by up to 80%
- Chlamydia by up to 90%
- It’s less effective for gonorrhoea, as that infection is already showing more antibiotic resistance.
Who’s It For?
Right now, Doxy-PEP is mainly recommended for gay, bisexual and other men who have sex with men (GBMSM) — especially if you’ve had a recent STI, or are planning a higher-risk time, like a big festival or travel period.
What to Keep in Mind
Doxy-PEP isn’t a “set and forget” solution. Because it’s an antibiotic, there are some things to think about:
- Antibiotic resistance – bacteria can adapt and become harder to treat.
- Gut health – doxycycline can affect your “good” bacteria.
- That’s why experts recommend using Doxy-PEP for short periods (around 3–6 months) and checking in with your clinician regularly.
Stay on Top of Testing
Even if you’re using Doxy-PEP, regular STI testing every 3 months is still key. Keep using your other prevention tools too — like condoms and PrEP.
Talk About It
Doxy-PEP can be a useful option for some, but it’s not for everyone. The best way to know if it fits your life is to chat with your doctor or sexual health clinic.
