This page is general health information, not medical advice. It cannot tell you whether you have an infection. A clinician can, and the testing options on this site are a good place to start.

Doxy-PEP is a way to lower the chance of certain bacterial infections after sex. The name stands for doxycycline post-exposure prophylaxis. A clinician prescribes it, and a person takes it after sex, not before.

CDC published national guidance on doxy PEP in 2024. This page explains what that guidance says, what the research suggests, and how doxypep care works in New York City.

What doxy-PEP is

Doxycycline is an antibiotic in the tetracycline class. It is a semisynthetic compound, which means it is made in a lab from a naturally occurring antibiotic family. It works by interfering with how bacteria build proteins, which slows or stops their growth.

That is the key point for understanding doxy-PEP. Doxycycline acts on bacteria. It does not act on viruses.

In doxy-PEP, a clinician prescribes doxycycline for use after condomless sex. The aim is to lower the chance that certain bacteria take hold. Dosing and timing details are set by the prescriber, so this page does not list them.

What CDC recommends

The CDC's 2024 clinical guidelines on doxy-PEP, published in MMWR, recommend it for a specific group. That group is gay, bisexual and other men who have sex with men, and transgender women, who have had at least one bacterial STI in the past 12 months. The bacterial STIs counted are gonorrhea, chlamydia and syphilis.

The guidance is about people who report condomless oral, vaginal or anal sex. It is not a general recommendation for everyone.

CDC says the evidence is not strong enough to recommend doxy-PEP for cisgender women or for heterosexual men. A clinical trial in Kenya that enrolled cisgender women did not show a clear benefit. Research is still ongoing in these groups.

Whether doxy-PEP fits a particular person is a conversation for a clinician. They can review sexual history, past test results, other medicines and health conditions. Nobody can tell from an article whether it applies to them.

The 72-hour window

CDC's guidance describes doxy-PEP as something used after sex, and the window is within 72 hours. Sooner within that window is better according to the guidance. After 72 hours, CDC does not recommend it for that exposure.

This is a different timeline from other tools. HIV PEP, for example, is a separate medicine for a possible HIV exposure and has its own 72-hour window. Doxy-PEP does not protect against HIV, and HIV PEP does not protect against bacterial STIs. They are not interchangeable.

What research suggests

Several studies have looked at taking doxycycline after sex. Researchers describe their findings as observations from specific groups of people.

A large US trial of gay, bisexual and other men who have sex with men and transgender women, published in the New England Journal of Medicine in 2023, found fewer cases of chlamydia, gonorrhea and syphilis among participants who used doxy-PEP than among those who did not.
Earlier trials in France, including one called IPERGAY, also found lower rates of chlamydia and syphilis with post-exposure doxycycline.
Across studies, the effect looks strongest for chlamydia and syphilis. Research suggests a smaller effect for gonorrhea.

The smaller effect for gonorrhea has a reason. In some places, many gonorrhea strains already resist tetracycline antibiotics. CDC notes this when it explains why the benefit varies by infection.

What doxy-PEP does not prevent

Doxy-PEP is not protection against every STI. According to CDC, it is meant to reduce the chance of bacterial STIs, mainly syphilis, chlamydia and gonorrhea.

It does not prevent:

HIV
Herpes
HPV
Other viral infections
Pregnancy

Other tools cover those. Condoms lower the chance of many infections. PrEP lowers the chance of HIV. The HPV vaccine lowers the chance of the HPV types it covers. Many people use more than one tool at once.

Resistance concerns

Public health agencies take antibiotic resistance seriously. When many people take an antibiotic, bacteria that can survive it may become more common over time.

CDC's guidelines name two concerns. One is tetracycline resistance in gonorrhea, which may grow with wider use. The other is resistance in other bacteria, such as Staphylococcus aureus, that people carry in the body. CDC encourages monitoring for these changes.

This is one reason doxy-PEP is a clinician-guided option and not an over-the-counter habit. It is also why CDC ties the recommendation to people with a recent bacterial STI, where the expected benefit is clearest.

Safety profile and contraindications

Doxycycline has been used for decades and is well studied. Still, it is a prescription medicine, and clinicians review it for each person.

Side effects people commonly report in the research include:

Upset stomach or nausea
Increased sensitivity to sunlight, which can cause sunburn more easily
Irritation of the throat or esophagus, especially if the medicine is not taken with plenty of water

A clinician will want to know about:

Past allergic reactions to doxycycline or other tetracycline antibiotics
Pregnancy or plans to become pregnant, because tetracyclines are generally avoided in pregnancy
Other medicines and supplements, since some can affect how doxycycline is absorbed
Liver or kidney conditions and any history of esophageal problems

If a side effect worries you, call the prescriber or a pharmacist. Do not wait for the next visit.

Testing still matters

Doxy-PEP and testing work together. CDC's guidance says people who use doxy-PEP should keep getting regular STI testing, with bacterial STI screening about every 3 months, and should be offered HIV testing and prevention services.

Testing is how an infection is found. A clinician can then explain results and treatment. Chlamydia, gonorrhea, syphilis and trichomoniasis are curable with treatment from a clinician. HIV, herpes and HPV are not curable, but they are treatable or manageable.

To find a testing site, CDC runs a locator at gettested.cdc.gov. For New York City sites, see the guide to where to get tested in New York City.

Why this matters in New York City

The NYC Department of Health and Mental Hygiene (DOHMH) publishes yearly STI surveillance reports. Its 2024 report lists these citywide numbers:

Chlamydia: 760.16 cases per 100,000 people (62,774 cases)
Gonorrhea: 398.27 per 100,000 (32,889 cases)
Primary and secondary syphilis: 17.76 per 100,000 (1,467 cases)

The same report counts 37 cases of congenital syphilis in 2024. These are the infections doxy-PEP is aimed at reducing, so New York City is a place where this conversation comes up often in sexual health care.

Getting doxy-PEP in New York City

Doxy-PEP is available only with a prescription. Several New York City sites list doxypep among their services.

NYC Health sexual health clinics

The NYC Department of Health and Mental Hygiene runs Sexual Health Clinics. Its clinic page lists these open locations, and each offers STI testing, HIV testing, PrEP, PEP, doxypep, HPV vaccine and treatment:

Chelsea (Manhattan): 303 9th Avenue, First Floor, Manhattan, NY 10001. Monday to Friday, 8:30 a.m. to 3:30 p.m. A separate Chelsea Express Clinic is open Monday and Wednesday to Friday 8:30 a.m. to 3:30 p.m. and Tuesday 8:30 a.m. to 7 p.m.
Central Harlem (Manhattan): 2238 Fifth Avenue, First Floor, Manhattan, NY 10037. Monday to Friday, 8:30 a.m. to 3:30 p.m.
Fort Greene (Brooklyn): 295 Flatbush Avenue Extension, Brooklyn, NY 11201. Monday to Friday, 8:30 a.m. to 3:30 p.m., with an Express Clinic on the first floor.
Morrisania (The Bronx): 1309 Fulton Avenue, Second Floor, Bronx, NY 10456. Monday to Friday, 8:30 a.m. to 3:30 p.m.
Jamaica (Queens): 90-37 Parsons Boulevard, First Floor, Queens, NY 11432. Monday to Friday, 8:30 a.m. to 3:30 p.m.
Corona (Queens): 34-33 Junction Boulevard, First Floor, Queens, NY 11372. Monday to Wednesday and Friday 8:30 a.m. to 3:30 p.m., Thursday 8:30 a.m. to 7:15 p.m.

NYC Health says these clinics are low to no cost. Adults 19 and older are asked for insurance or a sliding-scale fee. No proof of income is required, no payment is collected at the clinic, and no one is turned away for inability to pay. Most services are walk-in only, and clinics may close early once they reach capacity.

For questions, the Sexual Health Clinic hotline is 347-396-7959, Monday to Friday, 9 a.m. to 3:30 p.m. NYC Health lists no separate phone number for each clinic. The clinic page also lists a 24/7 PEP hotline at 844-373-7692. That line is for HIV PEP, which is a different medicine.

NYC Health also says the Crown Heights and Riverside clinics are closed until further notice. It lists no open Sexual Health Clinic on Staten Island. The HPV vaccine at these clinics is offered only to patients receiving other sexual health services.

Callen-Lorde

Callen-Lorde is a community health center focused on LGBTQ+ health. Its Chelsea site is at 356 W 18th St, New York, NY 10011, phone 212-271-7200. Callen-Lorde lists doxypep, PrEP, PEP, HIV and STI testing and treatment among its services.

Sexual health visits there are by appointment Monday to Friday with limited walk-in. Saturday walk-in runs 9 a.m. to 3 p.m., first come, first served. Callen-Lorde says it serves people regardless of ability to pay, with a sliding fee for people who are uninsured or underinsured. Visit co-pays range from $0 to $100.

Callen-Lorde also has a Bronx site at 555 Bergen Ave, 4th Floor (718-215-1800) and a Brooklyn site at 40 Flatbush Ave Ext, 3rd Floor (718-215-1818). Its sexual health page names only the Chelsea site, so check with the center about what each site offers.

Mount Sinai Adolescent Health Center

This center serves young people ages 10 to 26 at 312-320 East 94th Street, New York, NY 10128. The phone is 212-423-3000. Mount Sinai says its services are completely free and lists walk-in hours Monday to Saturday, 8:30 a.m. to 4:00 p.m., plus scheduled visits. It lists doxypep, STI testing, HIV testing including same-day rapid testing, PrEP, PEP and treatment.

For a quick overview of every site, see the list of New York City testing clinics.

Quality and sourcing: what to look for

Because doxy-PEP is a prescription medicine, the safest source is a licensed clinician and a licensed pharmacy. A few indicators of quality care:

A clinician reviews your history, allergies, other medicines and pregnancy status before prescribing.
You receive clear written instructions from the prescriber or pharmacist.
A follow-up plan includes regular testing, as CDC's guidance describes.
The medicine is dispensed by a licensed pharmacy with your name on the label.

Be cautious about antibiotics offered without a prescription or without a clinician involved. Medicine of unknown origin may be the wrong strength, the wrong drug, or not stored properly. A clinic can answer questions about where to fill a prescription.

If you are under 21

New York Public Health Law Section 2305 lets a licensed physician diagnose, treat or prescribe for a person under 21 who is infected with or exposed to an STD without parental consent or knowledge. NYC Health says its Sexual Health Clinics serve anyone 12 or older without parental consent, regardless of immigration status. The clinics also provide PrEP to adolescents without a parent's permission.

What to ask at a visit

These questions can help you get the most from a conversation with a clinician:

Does CDC's doxy-PEP guidance apply to my situation, and what are the alternatives?
Which tests should I have before starting, and how often afterward?
What side effects should I watch for, and who should I call about them?
How does this fit with PrEP, condoms and vaccines?
What should I do if more than 72 hours have passed?

Doxy-PEP is one tool among several. Regular testing, vaccines and conversations with partners also matter, and a clinician can help you choose a mix that fits your life.

Doxy-PEP in New York City: Who It Is For and How to Get It