PrEP

PrEP stands for pre-exposure prophylaxis. It's a medication taken by people who don't have HIV to stop them from getting it. When taken consistently, it's over 99% effective at preventing HIV infection. It's available free on the NHS in the UK and is one of the most significant advances in HIV prevention ever developed.

• PrEP is a pill taken by HIV-negative people to prevent HIV infection.
• Over 99% effective when taken as prescribed.
• Available free on the NHS through sexual health clinics.
• It can be taken daily or "on demand" (around the time of sex) depending on the type and your situation. [CHECK: current NHS guidance on event-based dosing eligibility]
• PrEP prevents HIV only — it doesn't protect against other STIs.

[DIAGRAM: Infographic showing how PrEP works — daily pill or event-based dosing, effectiveness rate, who it's for]

How it works

PrEP contains antiretroviral drugs — the same class of medication used to treat HIV. When the drugs are present in your body at the time of exposure, they prevent HIV from establishing an infection. The virus enters the body but can't take hold and replicate because the medication blocks it.

The most commonly prescribed PrEP in the UK is a combination of tenofovir and emtricitabine (brand name Truvada or generic equivalents). [CHECK: current NHS-prescribed PrEP medication]

How to take it

There are two approaches:

Daily PrEP — one tablet every day, at roughly the same time. This provides continuous protection and is the standard approach. It takes about 7 days of daily use to reach full protection for anal sex, and about 21 days for vaginal sex. [CHECK: current guidance on time to full protection]

Event-based (on-demand) PrEP — taking tablets around the time you have sex rather than every day. This involves taking two tablets 2-24 hours before sex, then one tablet 24 hours after the first dose, and another 24 hours after that. This approach is currently recommended mainly for men who have sex with men and for anal sex specifically. [CHECK: current eligibility for event-based dosing]

Your clinic will advise which approach is right for you.

Who it's for

PrEP is for anyone at higher risk of HIV who wants extra protection. In the UK, it's most commonly used by:

• Gay and bisexual men who have condomless anal sex
• People with an HIV-positive partner (though if the partner is on treatment and undetectable, the risk is already zero — U=U)
• Anyone who has frequent condomless sex with partners whose HIV status they don't know
• People who share injecting equipment

But PrEP is available to anyone at risk, regardless of gender or sexuality. If you think you might benefit, a sexual health clinic can assess your situation.

Getting PrEP

PrEP is free on the NHS. You access it through sexual health clinics (not GPs, in most cases). The process involves an initial appointment where you'll have an HIV test (PrEP is only for people who are HIV-negative), kidney function tests (the medication can affect kidneys in rare cases), and a conversation about your risk and whether PrEP is appropriate.

You'll then have regular check-ups — usually every 3 months — including HIV testing and STI screening. [CHECK: current follow-up schedule]

PrEP vs PEP

People sometimes confuse these:

• PrEP = before exposure. Taken regularly to prevent HIV before you're exposed.
• PEP = after exposure. Emergency medication taken within 72 hours of a potential exposure.

They're different tools for different situations. If you're regularly at risk, PrEP is the proactive option. If something unexpected happens (condom breaking, for example), PEP is the emergency backup.

Things people get wrong

"PrEP is only for gay men." It's most commonly used by gay and bisexual men, but it's available to anyone at risk of HIV — including straight people, women, and trans people.

"If you're on PrEP, you don't need condoms." PrEP only prevents HIV. It doesn't protect against any other STIs — chlamydia, gonorrhoea, syphilis, and others can all still be passed on. Condoms alongside PrEP give the most comprehensive protection.

"Taking PrEP means you're irresponsible." The opposite — it means you're taking active steps to protect your health. There's nothing irresponsible about preventing a serious infection.

"PrEP is the same as HIV treatment." PrEP uses some of the same drugs, but it's taken by HIV-negative people to stay negative. HIV treatment (ART) is taken by people who have HIV to manage the virus.

Things people ask about PrEP

Can I get PrEP if I'm under 18?

Yes. There's no age restriction on PrEP in the UK. If a clinic assesses that you're at risk and would benefit from it, it can be prescribed. [CHECK: any specific considerations for under-18s accessing PrEP]

Does PrEP have side effects?

Some people experience mild side effects in the first few weeks — nausea, headaches, or tiredness. These usually settle. Long-term, the main thing monitored is kidney function, which is checked at your regular appointments.

How do I ask for PrEP without it being awkward?

Sexual health clinics deal with this every day. You can just say "I'd like to talk about PrEP." They'll guide you through the rest. It's a routine part of their work.

If my partner is undetectable (U=U), do I still need PrEP?

If your partner is on effective treatment and has an undetectable viral load, they can't pass on HIV — that's what U=U means. In that case, PrEP isn't medically necessary, though some people choose to take it for additional peace of mind.

Where to get help

• Sexual health clinics (GUM clinics) — PrEP prescribing, testing, and ongoing monitoring. Free and confidential.
• Terrence Higgins Trust — information about PrEP, including how to access it and what to expect.
• I Want PrEP Now — information about PrEP access in the UK. [CHECK: whether this service is still active and current]

PrEP stands for pre-exposure prophylaxis. It's a pill that people who don't have HIV can take to protect themselves from getting it. When taken properly, it stops HIV more than 99% of the time.

It works because the medicine is already in your body when the virus tries to get in. The virus can't take hold because the medicine blocks it.

Most people take one pill every day. It takes about a week of daily use to be fully effective. Some people take it only around the time they have sex instead of every day — a clinic can advise which approach is right.

PrEP is free on the NHS. You get it from a sexual health clinic, not your usual doctor. You'll have a quick HIV test first (because PrEP is only for people who don't already have HIV) and then regular check-ups every few months.

PrEP only protects against HIV. It doesn't stop other infections passed on through sex. Using condoms as well gives the most complete protection.

Anyone at risk of HIV can use PrEP, regardless of gender or who they're attracted to. It's most commonly used by gay and bisexual men, but it's available to anyone who needs it.

PrEP is different from PEP. PrEP is taken before a risk to prevent HIV. PEP is emergency medicine taken after a risk has already happened.