Prevent STIs with DoxyPEP

There’s a revolutionary new way to prevent STIs: DoxyPEP.

Taking DoxyPEP after sex can reduce your chance of getting certain STIs like syphilis, chlamydia, and gonorrhea.

If you’re concerned about STIs or have a history of STIs, talk to your healthcare provider about DoxyPEP now. DoxyPEP won’t interfere with your other preventive or affirming care like PrEP, HIV medications, and hormones.

Is it effective?

DoxyPEP has been shown to drastically reduce bacterial STIs like syphilis, chlamydia, and gonorrhea. It’s supposed to be taken within 72 hours of having sex, so it’s best to get a prescription ahead of time.

Is it safe?

  • DoxyPEP uses an antibiotic, doxycycline, as post-exposure prophylaxis. Doxycycline is: 
    • Safe and has very few side effects. 
    • Inexpensive, even if you don’t have health insurance. 
    • Used to treat respiratory infections and even acne.
    • Safe to use alongside other medications such as HIV PrEP, HIV medications, hormones, and blockers.

Does it protect me from all STIs?

  • DoxyPEP is:
    • Only used to prevent bacterial STIs, like syphilis, chlamydia, and gonorrhea.
    • Not effective against HIV or other viral STIs, like herpes, HPV, or Mpox. 

    You’ll need HIV PrEP or PEP to protect yourself from HIV.

Is DoxyPEP right for me?

When it comes to a prevention plan, only you know if DoxyPEP is right for you. But DoxyPEP is encouraged if you:

  • Identify as a gay, bisexual, or other man who has sex with men. 
  • Identify as a transgender woman.
  • Are currently on, have been on, or are considering HIV PrEP.
  • Have sex with more than one partner.
  • Prefer to have sex without a condom.
  • Have a history of STIs or are concerned about potential exposure to STIs.

Ready to get DoxyPEP? Here’s how:

    1. Talk to a medical provider. They can prescribe DoxyPEP in person or virtually. You can also use a telehealth prescription service.
    2. Visit a sexual health clinic. Providers at PrEP Centers of Excellence can also prescribe DoxyPEP.
    3. Plan ahead. Have DoxyPEP on hand to take as soon as possible after sex.

Tell me more

Doxycycline is a common antibiotic that’s been used since the 1960s. Using it as a post-exposure prophylaxis (DoxyPEP) to prevent STIs is new, but it has been studied and endorsed.

  • DoxyPEP was studied in men who have sex with men and transgender women and showed an impressive overall 65% reduction in new STI infections. 
    • The risk of chlamydia was reduced by 88%, syphilis by 87%, and gonorrhea by 55%.
  • The California Department of Public Health has endorsed the use of doxycycline as DoxyPEP. 
  • Los Angeles County Department of Public Health recommends DoxyPEP for:
    • Transgender women and men who are gay, bisexual, or have sex with men who have had at least one bacterial STI in the past 12 months. 
    • People who have condomless sex with multiple partners and are at elevated risk of an STI. 
  • Researchers are examining how frequent doxycycline use could affect antibiotic resistance and the gut microbiome.


No. DoxyPEP is a one-time dose of doxycycline taken when you’ve had condomless sex. Try to take it as soon as possible after sex (when it’s most effective), although you can take it as long as 72 hours after sex.

Yes, you are protected as long as your last dose is no later than 72 hours after you last had sex.

Side effects are usually mild and might include nausea, light sensitivity, and vomiting. But you can reduce side effects by:

    • Taking it with a full stomach
    • Drinking plenty of water
    • Waiting 30 minutes before lying down
    • Wearing sunscreen

DoxyPEP can cause an upset stomach and other gastrointestinal problems, but these symptoms are usually mild. Speak with your provider if your symptoms get worse. 

There is a potential that using antibiotics can lead to more antibiotic-resistant infections, but the data is limited. Because DoxyPEP can significantly reduce bacterial STIs, the benefits outweigh the risks.

Absolutely! You can get DoxyPEP for a low cost or free—even if you don’t have insurance. It’s meant to be affordable. (If you need health insurance, Covered California or Medi-Cal can help.)

There are medications that can be taken within 72 hours of having sex (PEP) to reduce transmission of STIs: DoxyPEP and HIV PEP.

    • DoxyPEP is taken after having sex (PEP), when you think you have been exposed to bacterial STIs such as syphilis, chlamydia, and gonorrhea.
    • HIV PEP is taken after having sex (PEP), when you think you have been exposed to HIV.

In addition to taking DoxyPEP and HIV PEP, make sure to visit your healthcare provider and get tested for STIs including syphilis, chlamydia, gonorrhea, and HIV.

  • HIV PrEP is taken before having sex (PrEP). It reduces the transmission of HIV. 
  • HIV PEP is taken after having sex (PEP), when you think you might have been exposed to HIV
  • DoxyPEP is taken after having sex (PEP), when you think you might have been exposed to bacterial  STIs such as syphilis, chlamydia, and gonorrhea.

Absolutely. DoxyPEP is extremely effective, but it’s not 100%. If you have any symptoms of an STI, be sure to get checked and treated. It’s a good idea to get tested for STIs every 3–4 months while taking DoxyPEP.

It’s currently being tested for wider use in different groups of people. STI prevention should be tailored to your needs. If you are concerned about exposure to STIs, discuss with your provider to see if it would be appropriate for you.

Yes! Studies show that DoxyPEP has no effect on treatment, viral load, or undetectable status and is safe to use with HIV-related medications.