HIV PrEP (a pill to prevent HIV) (HIV pre-exposure prophylaxis (PrEP))

A medicine taken by people who do not have HIV to greatly reduce their chance of getting it from sex, when taken as directed.

✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review

In short

Taken correctly, PrEP greatly reduces the chance of getting HIV from sex (around 99%) — but only when taken as directed.
PrEP does not protect against other STIs or pregnancy, so many people use condoms as well.
You need an HIV test before starting, and regular HIV/STI testing and kidney checks while on it.
It is free on the NHS from sexual health clinics for eligible people; it can be taken daily or, for some, around the time of sex.

A plain-English summary. The detail — including risks and recovery — is below.

At a glance

TypePreventive medical treatment (tablets, taken daily or around sex)

AnaestheticNot needed

How long it takesAn initial appointment, then ongoing while you need protection

Hospital stayUsually no hospital stay

Time off workUsually none

When you'll see resultsProtection builds up over a few days of taking it; you have regular HIV and STI testing while on it

On the NHS?Free on the NHS from sexual health clinics for eligible people

A general guide. Your specialist will give you advice for your situation.

Best fit

Greatly reduces the chance of getting HIV from sex when taken as directed

Pause if

You already have HIV — you need HIV treatment, not PrEP (which is why testing first is essential).

Main recovery point

HIV test confirms you are negative; STI, hepatitis and kidney checks are done. PrEP is started only once HIV-negative is confirmed.

Good aftercare

A clear dosing plan and a named contact for questions.

Before starting

HIV test confirms you are negative; STI, hepatitis and kidney checks are done. PrEP is started only once...

First days

Protection builds up over several days. Your clinic will tell you exactly when you are protected for the type of...

First weeks

Any early side effects such as nausea or headache typically ease. Contact the clinic if they are troublesome...

Every ~3 months

Regular HIV and STI testing while you remain on PrEP, so anything is picked up early.

Medical line illustration of hiv prep pep consultation for HIV PrEP (a pill to prevent HIV). — Illustration only - not a diagnosis, medical advice or a promise of result. Your anatomy and treatment plan may differ. Vuemedics does not publish before-and-after photos.

What is HIV PrEP?

PrEP (pre-exposure prophylaxis) is a medicine taken by people who do not have HIV to stop them getting it. It usually contains two anti-HIV drugs (tenofovir disoproxil and emtricitabine). If you are exposed to HIV, the medicine already in your body helps stop the virus taking hold.

Taken as directed, PrEP is highly effective — it reduces the risk of getting HIV from sex by around 99%. Its effectiveness depends on taking it correctly; missed doses lower how well it works. It can be taken every day, or, for some people and types of sex, around the time of sex ('event-based' dosing). A clinician will help you choose.

PrEP only protects against HIV. It does not protect against other STIs such as gonorrhoea, chlamydia, syphilis or hepatitis C, and it does not prevent pregnancy. Many people use condoms as well to cover these.

PrEP is not a one-off. You need an HIV test before starting (to be sure you do not already have HIV), and regular HIV and STI testing and kidney checks while you take it. It is free on the NHS from sexual health clinics for people who are eligible.

Types, options & approaches

There may be different ways to do this. The right approach depends on the clinical question and your circumstances.

Daily PrEP

One tablet taken every day. Suitable for most people and all types of sex. Protection builds up over the first days of taking it.

Event-based (on-demand) PrEP

Tablets taken around the time of sex (for example, a double dose 2–24 hours before, then one a day until two days after the last sex). Generally used for anal sex in men who have sex with men, on a clinician's advice.

Generic PrEP

Most PrEP used in the UK is a generic version containing the same active drugs as the original brand (Truvada). It works the same way.

Newer PrEP options

Other formulations and longer-acting options are emerging. Your clinic can tell you what is currently available to you on the NHS and whether they suit your situation.

PrEP vs PEP

	PrEP	PEP
When taken	Before/around sex, ongoing	After a possible exposure
Timing	Planned protection	Emergency: within 72 hours
Course	Ongoing while at risk	28 days, one-off
Best for	Repeated or expected risk	A specific recent exposure

PrEP is the planned way to stay protected if you are often at risk; PEP is an emergency measure for a specific exposure. Neither protects against other STIs.

Preparing for your treatment

Have an HIV test first — PrEP must only be started once you are confirmed HIV-negative.
Expect tests for other STIs, hepatitis B and C, and a check of your kidney function before starting.
Tell the clinician about all your medicines and any kidney or bone problems.
Talk through whether daily or event-based dosing suits the sex you have.
Be honest about how reliably you can take tablets, as this affects which option is safest.
Plan for regular follow-up — PrEP comes with ongoing testing, not just a prescription.

What happens

At your first appointment, a clinician asks about your sexual health and risk, and arranges an HIV test plus tests for other STIs, hepatitis and kidney function. PrEP is only started once you are confirmed HIV-negative.

You will agree a dosing plan — daily or, for some people, event-based — and be told how long it takes for protection to build up. You will be shown how and when to take it, and what to do if you miss a dose.

While on PrEP you return regularly (often every three months) for repeat HIV and STI testing and, periodically, kidney checks. This monitoring is part of using PrEP safely, not an optional extra.

Is this treatment right for me?

A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.

May not be suitable if…

You already have HIV — you need HIV treatment, not PrEP (which is why testing first is essential).
Significant kidney problems may make standard PrEP unsuitable; the clinic will assess this.
You are very unlikely to be exposed to HIV, where the testing and monitoring burden may not be justified.
You cannot commit to the dosing and regular monitoring that safe PrEP use requires.

Delay or rearrange if…

You have a flu-like illness or possible recent HIV exposure — testing needs to clarify your HIV status first.
Your HIV status is not yet confirmed negative.
Kidney function needs checking or optimising before starting.
You are within 72 hours of a high-risk exposure and unprotected — PEP may be needed first, then transition to PrEP.

Alternatives to discuss

Condoms, which also protect against other STIs and pregnancy.
PEP for a specific recent exposure (within 72 hours), rather than ongoing PrEP.
Treatment as prevention: a partner with HIV on treatment with an undetectable viral load cannot pass it on (U=U).
Regular testing and risk-reduction advice if PrEP is not wanted or suitable.

Before you decide

Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.

What matters most to me?

Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.

What are all my options?

Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.

What would make me pause?

Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.

What happens if I do nothing today?

For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.

Benefits

Greatly reduces the chance of getting HIV from sex when taken as directed
Puts protection in your control, separate from a partner's actions
Comes with regular STI testing, so other infections are picked up and treated
Free on the NHS for eligible people
Can be stopped and restarted as your circumstances change, on clinical advice

Risks & complications

More common

Mild side effects in the first weeks, such as nausea, tummy upset, headache or tiredness, which usually settle
The commitment of regular testing and follow-up appointments
Needing to remember doses reliably for it to work

Less common

Side effects that persist or are troublesome enough to need a review
A small effect on kidney function in some people, which is why it is monitored
A small reduction in bone density with long-term use, usually reversible after stopping

Rare but serious

Starting PrEP while unknowingly already HIV-positive, which can encourage drug resistance — this is why testing first is essential
More significant kidney problems, which monitoring is designed to catch early
PrEP failing despite correct use, which is very rare but not impossible

The most important safety points are testing HIV-negative before starting and taking PrEP reliably. PrEP gives no protection against other STIs or pregnancy, so think about condoms and contraception separately. Tell the clinic about kidney or bone problems, as these affect monitoring and suitability.

Published figures to discuss

How well PrEP works in real life depends heavily on how reliably it is taken. In people who take it as directed it is highly effective at preventing HIV from sex. Side effects are usually mild and early. We give a headline effectiveness figure from large studies and guidance, but keep risk wording cautious because individual results depend on adherence and the type of sex.

Figure	Reported range	How to interpret it	Source / confidence
HIV prevention from sex (taken as directed)	Around 99% reduction in risk	Depends on taking PrEP correctly; effectiveness is lower with missed doses.	GOV.UK — Landmark study confirms effectiveness of PrEPgov.ukPublished figure
Protection against other STIs	None	PrEP prevents HIV only; condoms, vaccination and regular STI testing still matter.	Guide sourcesClinical context
Starting PrEP during undiagnosed HIV infection	Avoidable with testing	A negative HIV test is required before starting and at follow-up to reduce resistance risk.	GOV.UK — Landmark study confirms effectiveness of PrEPgov.ukSource-linked context
Kidney or hepatitis B monitoring issue	Patient-specific	Oral tenofovir-based PrEP needs renal assessment and careful advice if hepatitis B infection is present.	GOV.UK — Landmark study confirms effectiveness of PrEPgov.ukSource-linked context

These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.

What happens afterwards

There is no recovery as such — PrEP is an ongoing treatment. Protection builds up over the first days of taking it, and using PrEP well means keeping up with doses and regular testing.

Before starting

HIV test confirms you are negative; STI, hepatitis and kidney checks are done. PrEP is started only once HIV-negative is confirmed.

First days

Protection builds up over several days. Your clinic will tell you exactly when you are protected for the type of sex you have. Mild side effects may appear and usually settle.

First weeks

Any early side effects such as nausea or headache typically ease. Contact the clinic if they are troublesome rather than stopping on your own.

Every ~3 months

Regular HIV and STI testing while you remain on PrEP, so anything is picked up early.

Periodically

Kidney function checks (and bone health considered with long-term use) to use PrEP safely over time.

If you stop

Stop only after advice — there are safe ways to stop, and protection ends once the medicine is out of your system.

What's normal — and not a worry

Mild nausea, tummy upset or headache in the first weeks that usually settles
No physical change you can feel once settled — the protection works quietly
A routine of regular testing appointments becoming part of your year
Needing a short build-up period before you are fully protected

Aftercare

Take PrEP exactly as agreed — daily, or the event-based schedule your clinic gave you.
If you miss doses, follow your clinic's advice; do not assume you are still protected.
Keep all follow-up appointments for HIV/STI testing and kidney checks.
Use condoms if you also want protection from other STIs and pregnancy.
Tell any other doctor or pharmacist you take PrEP, because of medicine interactions.
Talk to the clinic before stopping, so you stop safely.
Test promptly if you notice symptoms of an STI or a flu-like illness.

Before your treatment

Your agreed dosing schedule written down
A reliable reminder system for taking tablets
Your next testing appointment booked
Condoms if you want STI/pregnancy protection too
The clinic's contact details saved
Knowing when, after starting, you are actually protected

⚠ Get urgent help if…

A flu-like illness (fever, sore throat, rash) after a possible exposure — this can be early HIV and needs urgent testing
Symptoms of another STI, such as discharge, sores, pain passing urine or pelvic pain
Severe or persistent nausea, vomiting or tummy pain
Reduced or unusually frothy urine, or swelling — possible kidney effects
Yellowing of the skin or eyes
Signs of an allergic reaction such as a spreading rash or swelling

Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.

General guidance — it doesn't replace the specific advice your specialist gives you.

Results & realistic expectations

Used as directed, PrEP greatly lowers your chance of getting HIV from sex. A good outcome is staying HIV-negative on your regular tests while you remain at risk and on PrEP.

PrEP does not protect against other STIs, so a negative HIV test does not mean you are clear of everything — the regular STI testing that comes with PrEP is there to catch those. Effectiveness depends on taking it correctly, so honest conversations about adherence matter.

How long it lasts

PrEP works only while you are taking it and while the drug is in your system; protection ends after you stop. You can take it for as long as you remain at risk, and you can stop and restart as your life changes, on clinical advice. Regular monitoring continues for as long as you are on it.

Related tests, treatments or support

PrEP is usually combined with regular STI screening, hepatitis B vaccination if needed, and contraception advice where relevant. Many people use condoms alongside PrEP to cover other STIs and pregnancy. If you have a recent high-risk exposure and are not yet protected, PEP may be needed instead.

Follow-up & long-term care

Follow-up is built into PrEP: regular HIV and STI testing (often every three months) and periodic kidney checks. This is how PrEP is used safely, and it is also a chance to review your dosing and whether PrEP still suits you.

Take doses reliably on your agreed schedule
Attend regular HIV and STI testing
Have kidney function checked as advised
Review your dosing choice with the clinic as your life and risk change
Top up condoms and think about contraception separately

Repeat, follow-on and what comes next

Dosing can be switched between daily and event-based as your needs change, on clinical advice.
PrEP can be paused and restarted safely around periods of higher and lower risk.
If kidney function changes, the clinic may adjust monitoring or review the medicine.
Regular testing means other STIs are found and treated promptly while you are on PrEP.

Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.

What good aftercare looks like

A clear dosing plan and a named contact for questions.
Regular HIV and STI testing built in, usually every three months.
Periodic kidney checks and attention to bone health with long-term use.
A clear plan for what to do about missed doses or a possible exposure.
Support to stop safely, and to restart, as your circumstances change.

What affects the cost

Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:

On the NHS, PrEP and its monitoring are free for eligible people.
If using a private service, the consultation and prescribing fees.
The ongoing cost of the medicine if bought privately.
Regular HIV and STI testing and kidney checks if not done through the NHS.
Follow-up appointments to review dosing and results.

Make sure your written quote includes

Confirmation of whether you are eligible for free NHS PrEP
If private: consultation and prescribing fees and who you will see
If private: the ongoing cost of the medicine
What testing and monitoring is included and how often
How results are given and who to contact between visits
What happens if you need to switch dosing, pause, or stop

On the NHS? PrEP is free on the NHS from sexual health clinics for eligible people; some use private services for speed or choice, but eligibility for free NHS PrEP is broad and worth checking first.

You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.

Choosing a specialist safely

Check the specialist is on the GMC Specialist Register for this area.
Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
You're entitled to your total cost in writing — including any follow-up — before you decide.

How Vuemedics verifies every consultant →

Questions to ask your medical professional

Take this to your consultation. A good specialist will welcome every one of these.

Is daily or event-based PrEP more suitable for the sex I have?
Exactly how long after starting am I protected, and for which types of sex?
How often will I need HIV and STI testing and kidney checks?
What should I do if I miss one or more doses?
Could PrEP interact with my other medicines or affect my kidneys or bones?
How do I stop safely if my circumstances change?
Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
Will you be the specialist who carries out my treatment, and who looks after me afterwards?
What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
What does a realistic result look like — and what can this treatment not achieve?
What are my options, including waiting, doing nothing for now, or choosing a different approach?
Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
What is the total cost in writing, including any follow-ups, and how much time do I have to decide?

Frequently asked questions

How well does PrEP work?

Taken as directed, PrEP reduces the risk of getting HIV from sex by around 99%. Effectiveness depends on taking it correctly — missed doses lower how well it works.

Does PrEP protect against other STIs?

No. PrEP only protects against HIV. It does not protect against gonorrhoea, chlamydia, syphilis, hepatitis C or other STIs, and it does not prevent pregnancy. Many people use condoms as well.

Is PrEP free on the NHS?

Yes, PrEP is free on the NHS from sexual health clinics for eligible people. The clinic can tell you whether you are eligible and arrange the testing that goes with it.

Do I have to take it every day?

Not necessarily. Daily dosing suits most people and all types of sex. For some people and types of sex, event-based ('on-demand') dosing is an option. A clinician will help you choose.

Why do I need so many tests?

An HIV test before starting confirms you are negative (starting PrEP with undiagnosed HIV can cause drug resistance). Ongoing HIV and STI testing and kidney checks keep PrEP safe and pick up other infections early.

Can I stop PrEP if my situation changes?

Yes. PrEP can be stopped and restarted as your risk changes, but speak to the clinic first so you stop safely. Protection ends once the medicine is out of your system.

What if I have a sudden high-risk exposure and I'm not protected yet?

If you are within 72 hours of a possible exposure and not yet protected, PEP (emergency anti-HIV medicine) may be needed. Contact a clinic or A&E straight away.

Find a verified specialist for hiv prep (a pill to prevent hiv)

Every consultant is GMC-checked and independently reviewed. Search by postcode and distance, or switch to a map. Ordered by rating, relevance and recency — never by who pays.

No verified consultants list this procedure yet — browse the full directory.

See all specialists for hiv prep (a pill to prevent hiv) →

How we made this page

Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →

Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.

Sources & standards: Terrence Higgins Trust — PrEP NHS — HIV and AIDS iCaSH (NHS) — PrEP for HIV GOV.UK — Landmark study confirms effectiveness of PrEP UKHSA — PrEP monitoring and evaluation framework for England

Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.

Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.