PrEP, PEP, doxyPEP and STI testing for gay and bi men

If you meet men from apps, sexual health is part of the deal, and the good news is that the tools have never been better. You can now prevent HIV with a pill, an injection every two months or an injection twice a year; take an antibiotic after sex to cut your chance of syphilis and chlamydia; and get tested for free in most of the country. This guide covers what each option is, what the official guidance says, and how to get it without paying much or anything.

It isn't medical advice for your situation. It is a map, so the conversation with a clinician, or a telehealth service, goes quicker.

PrEP: preventing HIV before you're exposed

PrEP (pre-exposure prophylaxis) is HIV medicine taken by HIV-negative people to stay negative. According to HIV.gov, it reduces the risk of getting HIV from sex by about 99% when taken as prescribed. It is much less effective when doses are missed, so the best option is the one you will actually stick to. There are four:

Yeztugo is the newest. The FDA approved it in June 2025, and in Gilead's announcement of the approval, 99.9% of participants in the trial that included cisgender men and gender-diverse people did not acquire HIV, with two infections among 2,179 people. If you're bad at daily pills, two injections a year is a real change.

How long until it works

The CDC says daily pills reach maximum protection for receptive anal sex after about 7 days, and for receptive vaginal sex and injection drug use after about 21 days. There is no data yet for the insertive partner. For injections, follow your provider's instructions: some start with pills.

On-demand ("2-1-1") PrEP

You may have heard of taking PrEP only around sex: two pills 2 to 24 hours before, then one pill 24 hours after the first dose and one more 24 hours after that. The CDC says evidence supports this for gay and bi men having anal sex, but that it is not FDA-approved and not recommended by the CDC; daily dosing is the only approved schedule for pills. Many clinicians outside the US do prescribe it. If you want to use it, talk to a provider rather than improvising, because it only works with Truvada or its generics and only with the dosing done right.

What it costs

Usually nothing. HIV.gov says PrEP is a preventive service that most insurance must cover without a co-pay, even before your deductible, along with the visits and lab tests that go with it. That requirement survived a Supreme Court challenge: in Kennedy v. Braidwood Management, decided June 27, 2025, the Court upheld the way the US Preventive Services Task Force, whose recommendations trigger that free coverage, is appointed. Medicaid in many states and Medicare Part B also cover PrEP with no out-of-pocket cost.

No insurance? Manufacturers run assistance programs that provide the drug free to eligible uninsured people, many states run PrEP assistance programs, and community health centers charge on a sliding scale. HIV.gov lists them all, with a provider locator.

PEP: if something already happened

PEP (post-exposure prophylaxis) is a 28-day course of HIV medicine that prevents infection after a possible exposure: a condom broke, you weren't on PrEP, or you were assaulted. According to HIV.gov, it must be started within 72 hours, and the sooner the better. Go to an emergency room, urgent care, or a sexual health clinic and say the word "PEP". Don't wait until Monday. If you need PEP more than once, that is a sign PrEP would suit you better.

U=U: what an undetectable partner means

People living with HIV who take treatment and keep an undetectable viral load do not transmit HIV through sex. This is the message of the Prevention Access Campaign's U=U (undetectable equals untransmittable), and it is backed by large studies and by public health agencies. A guy who tells you he's positive and undetectable is giving you useful, honest information; he is not a risk to avoid. Treat that disclosure with the respect it took to make.

DoxyPEP: an antibiotic after sex

DoxyPEP is a single 200 mg dose of the antibiotic doxycycline taken within 72 hours after sex. In guidelines published in June 2024, the CDC said trials found it cut syphilis and chlamydia by more than 70% and gonorrhea by about half among gay and bi men and trans women. The CDC recommends that clinicians discuss doxyPEP with gay and bi men and trans women who have had syphilis, chlamydia or gonorrhea in the past 12 months.

It isn't a free pass: it does nothing against HIV, mpox or herpes, its effect on gonorrhea is weaker, and doctors are watching for antibiotic resistance. Take no more than 200 mg in 24 hours, and keep getting tested.

STI testing: what and how often

STIs are common and mostly easy to treat, but many have no symptoms, so testing is the only way to know. The CDC's treatment guidelines for men who have sex with men recommend testing at least once a year if you're sexually active, and every three to six months if you have multiple or anonymous partners, use PrEP, or use drugs during sex. A full screen usually means:

• HIV, by blood test.
• Syphilis, by blood test.
• Gonorrhea and chlamydia at every site you use: urine for the penis, a rectal swab if you bottom, and a throat swab for gonorrhea if you give oral sex. A urine test alone misses throat and rectal infections, so ask for "three-site testing". You can usually take the swabs yourself.
• Hepatitis B and C, at least once, and get vaccinated against hepatitis A and B if you aren't already.

Syphilis is the one to take seriously. The CDC's provisional 2024 data counted 190,242 syphilis cases, down 9% from 2023 after years of steep increases, but still far above where it was a decade ago. Untreated, it can damage the eyes, ears and nervous system. A course of penicillin cures it.

Mpox

The two-dose JYNNEOS vaccine protects against mpox. The CDC recommends it for gay and bi men and other people at risk. If you only had one dose in 2022, get the second.

Where to get all of this

• Free and low-cost testing: the CDC's GetTested finder lists HIV, STI and hepatitis testing near you by ZIP code, including free sites.
• Sexual health clinics run by health departments test and treat confidentially, often for free, and usually prescribe PrEP and PEP.
• Your regular doctor can do all of it. If you haven't told them you have sex with men, the CDC guidelines above are a useful thing to print and bring.
• Telehealth PrEP services mail home test kits and prescriptions. Grindr itself bought one, PurposeMed, the company behind the HIV-prevention service Freddie, in November 2026, according to Global Dating Insights. Read the privacy policy of any health service you use through a dating app company; our privacy guide explains why.

Talking about it on the apps

Most apps have fields for HIV status, last test date and PrEP. Filling them in normalises the conversation and helps you find men who think the same way. Leaving them blank is also fine; you can talk about it in chat. What matters is being honest when it's relevant, and treating other men's status, whatever it is, without judgement. Our guide to meeting safely covers consent and the rest of the night.

What to ask at your appointment

Many men put off sexual health appointments because they don't know what to say. You don't need to explain much. A clinic hears the same few things all day. These questions get you what you need:

• "I'd like a full STI screen, including throat and rectal swabs."
• "I'm interested in PrEP. Which options would suit me, and does my insurance cover the shots?"
• "I've had an STI in the last year. Is doxyPEP right for me?"
• "Am I up to date on hepatitis A and B and mpox vaccines?"
• "How often should I come back for testing, given how I'm having sex?"

You don't have to give a number of partners or describe anything you don't want to. What helps the clinician is knowing which sites to test and whether you use condoms consistently. If a provider is judgemental, go somewhere else: health department sexual health clinics and LGBTQ health centers are used to these conversations, and the CDC's guidelines give them clear instructions.

Testing and timing

No test detects HIV or every STI the day after an exposure. Each test has a window period, from days to weeks, before an infection shows up. If you're testing because of a specific worry, tell the clinic when it happened so they can choose the right test and tell you when to come back. If the exposure was in the last 72 hours, ask about PEP first, because that clock matters more.

PrEP itself comes with regular testing built in: HIV.gov says people on daily pills see a provider every three months, and people on injections every two or six months. That rhythm is a good one to keep even if you stop PrEP.

How effective is PrEP?

Very. HIV.gov says PrEP reduces the risk of getting HIV from sex by about 99% when taken as prescribed. It is much less effective with missed doses, which is why the two-monthly and twice-yearly injections are a big step for people who struggle with daily pills.

Is PrEP free?

For most insured people in the US, yes: PrEP and its tests are a preventive service that must be covered with no co-pay, a rule the Supreme Court left standing in 2025. Medicare Part B and many state Medicaid programs also cover it. Uninsured people can usually get it free through manufacturer or state assistance programs.

How often should gay men get tested for STIs?

The CDC says at least once a year for all sexually active gay and bi men, and every three to six months if you have multiple or anonymous partners, use PrEP or use drugs during sex. Ask for testing at every site you use, not just urine. Our hookup safety guide covers the rest of staying well.

Your next steps

1. Book a full screen, three sites, if your last one was more than three months ago.
2. If you're HIV-negative and having sex without condoms, ask about PrEP, including the injections.
3. If you've had an STI in the past year, ask about doxyPEP.
4. Save the location of your nearest emergency room or sexual health clinic for PEP, just in case.
5. Check your mpox and hepatitis vaccinations.