What PrEP is
PrEP is a tablet you take before any possible exposure to HIV. Taken correctly, it stops HIV from establishing itself if it does enter your body. It is preventive medicine — same logic as a flu jab, just delivered as a daily pill or as event-based dosing around sex.
It does not protect against any other STI. For chlamydia, gonorrhoea, syphilis or hepatitis, you still need regular testing and condom decisions made on their own merits.
What PEP is
PEP is the emergency version. If you think you have just been exposed to HIV — a condom break, a partner who is HIV-positive and not on treatment, an incident you are unsure about — PEP is a 28-day course of medication that can stop HIV taking hold.
The deadline is hard: within 72 hours of exposure, ideally within 24. After 72 hours it stops being effective. Sooner is always better than later.
Who PrEP is appropriate for
This is where the conversation often goes wrong. PrEP gets framed as something for men deemed "high-risk", which puts a lot of men off asking about it because nobody likes that label attached to their sex life.
The reality is simpler. If you have sex with men, even occasionally, even only with people you trust, even only inside long-standing arrangements, PrEP is a choice you are entitled to make. It is a tool, not a verdict on your behaviour.
Married men exploring with men, men in open relationships, men who hook up rarely, men who hook up often — PrEP is on the table for all of them. The decision is yours, made with a clinician, on your terms.
How to get PrEP free on the NHS
PrEP is free on the NHS via sexual health clinics in England, Scotland, Wales and Northern Ireland. You do not need a GP referral, you do not need to disclose anything to your GP, and the appointment is confidential.
The route is the same one you would use for any sexual health concern. You book or walk into a clinic, have a baseline screen (HIV, kidney function, other STIs), and if eligible you walk out with — or get prescribed — your first supply. Reviews follow every three months.
Use the NHS sexual health services finder to locate your nearest clinic — same route for both PrEP and walk-in PEP.
Side effects and what's known
For most men there are no significant side effects. A minority report mild stomach upset, headache or tiredness in the first few weeks, which usually settles. Most men stay on PrEP for years without trouble — kidney function and bone health generally hold up fine in healthy adults, which is what the three-monthly review monitors.
If something feels off, tell the clinic. They will adjust, switch formulation, or rule out an unrelated cause — they are not surprised by side-effect questions.
What PEP is for and how to access it urgently
PEP is for the moments PrEP wasn't on board. Condom split, unprotected sex with someone whose status you don't know, a sexual assault, a needle-stick, a one-off you regret — any plausible HIV exposure inside the last 72 hours is a reason to ask for PEP.
The two routes are simple. During clinic hours, go to your nearest sexual health clinic and ask for PEP. Outside hours, on weekends and bank holidays, go to A&E and tell triage you need PEP urgently — they know what it is.
You will be given the first doses on the spot, with the rest of the 28-day course arranged through follow-up. Bring a sense of timing rather than a sense of guilt — clinics treat thousands of these requests every year and don't moralise.
Common myths
"PrEP is only for men with lots of partners." Not true. PrEP is for any man who wants the protection it offers, full stop.
"PrEP replaces condoms." It doesn't. PrEP stops HIV; it does nothing for the other STIs condoms cover, which is why testing and condom choices are still part of the picture.
"You have to tell your GP." You don't. Sexual health clinics are confidential and PrEP records do not automatically go to your GP unless you ask them to.
"It's too late, the exposure was last week." For starting PrEP today, no — you can still start. For PEP, 72 hours is the cut-off; after that, the conversation shifts to early HIV testing and ongoing care.
If any of this is new to you, it is worth a clinic visit on its own. Both PrEP and PEP exist because men in your situation asked for them, and the system is there for you to use.
Read next: STI testing in the UK · Safety and consent · Your first time with a man