DoxyPEP is a morning-after pill for STIs – it can reduce the risk of getting STIs by up to 70% after having unprotected sex

What is DoxyPEP?

DoxyPEP involves taking doxycycline, an antibiotic, as a ‘Post-Exposure Prophylaxis’ for bacterial STIs after having sex without a condom. The idea is that taking doxycycline soon enough after unprotected sex will kill any STI-causing bacteria before it has the chance to cause a full-blown infection. 

While not as well studied as PrEP for HIV (Pre-Exposure Prophylaxis), preliminary findings have shown that taking DoxyPEP after sex could reduce the risk of STIs such as gonorrhoea, chlamydia and syphilis by up to 70%.

Doxycycline is currently widely used as a first-line treatment of choice for chlamydia, and in some cases syphilis and gonorrhea.

Taking DoxyPEP

DoxyPEP is taken as a single 200mg dose of oral Doxycycline within 72 hours after having sex without a condom.

DoxyPEP Effectiveness and Risks

Existing clinical trials with DoxyPEP have shown that it can reduce sexually transmitted infections by up to 70%.

Currently there are two key clinical trials supporting doxycycline as PEP for STIs, both studying men who have sex with men (MSM) and trans women:

  1. Trial conducted in Seattle and San Francisco (published in 2022): Doxycycline was shown to cut the risk of STIs by 66%
  2. Trial conducted in France (published in 2017): Doxycycline was shown to reduce the risk of chlamydia and syphilis by ~70% each
Some people may experience mild side effects from taking doxycycline, such as digestive symptoms and sensitive skin. However, based on the studies above, none of the participants stopped taking the drug because of problems tolerating its side effects.

Where to Get DoxyPEP

DoxyPEP is still a relatively new concept, and has not entered mainstream medicine or healthcare services yet.