What is DoxyPEP?

Doxycycline Post-Exposure Prophylaxis (DoxyPEP) means taking the antibiotic doxycycline after sex, to prevent getting a sexually transmitted infection (STI). It is a morning-after pill for STIs. Studies have shown that taking DoxyPEP reduces your chance of getting syphilis and chlamydia by about two-thirds, especially if you are a transgender woman (TGW) or a man who has sex with men (MSM).

When should I take DoxyPEP?

Two 100 mg of doxycycline should ideally be taken within 24 hours, but no later than 72 hours after condomless sex. Condomless sex means oral, anal, or vaginal/front-hole sex where a condom is not used for the entire time.

What about when I have sex again?

If you have sex again within 24 hours of taking doxycycline, take another dose 24 hours after your last dose. You can take doxycycline as often as every day when you are having condomless sex but do not take more than 200 mg (two 100 mg pills) every 24 hours.

How should I take DoxyPEP?

  • Take doxycycline with plenty of water or something else to drink so that it does not get stuck when you swallow. If your stomach is upset by doxycycline, taking it with food may help.
  • Some people are more sensitive to the sun when they take doxycycline, so wear sunscreen.
  • Please do not share doxycycline with others.
  • Avoid dairy products, calcium, antacids, or multivitamins 2 hours before after taking doxycycline.


  • Please continue to get tested for STIs every 3 months and whenever you have symptoms.
  • DoxyPEP doesn’t protect against MPOX (monkeypox), HIV, or other viral infections.
  • Talk to your health care provider about pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) for HIV prevention.
  • If you are living with HIV, continue to take your medications and see your health care provider regularly.