PrEP (pre-exposure-prophylaxis) is a pill that protects you from HIV. It's taken by HIV-negative people before and after sex.
Taking PrEP before and after sex means there’s enough drug inside you to block HIV if it gets into your body – before it has the chance to take hold. It’s highly effective at stopping HIV from being transmitted when taken correctly.
PrEP offers protection during vaginal/frontal and anal sex. It’s safe to use for trans women and trans feminine people and is effective regardless of any gender-affirming surgeries that you've had, including vaginoplasty.
PrEP and hormone treatment
PrEP doesn’t affect or interact with your hormone treatment.
The British HIV Association guidelines note that there are no known interactions between PrEP and gender-affirming hormones. PrEP will not stop any hormones you are taking from working.
PrEP does not cause fat redistribution in the body or face.
Is PrEP right for you?
PrEP might be right for you if you’re HIV negative and have sex in a variety of situations where condoms are not easily or always used. It gives you empowerment, particularly if you are a receptive partner, or bottom, by taking control over protecting yourself from HIV transmission.
How to take PrEP
The way you take PrEP depends on the type of sex you have, but generally daily dosing is recommended, especially for anyone who is taking gender-affirming hormones.
For anyone having vaginal or frontal sex, daily PrEP is the only option. This is to make sure PrEP levels are high enough in these tissues to provide protection against HIV. Daily PrEP needs to be taken for seven days until it becomes fully effective.
Another way of taking PrEP is 'on-demand dosing', sometimes called 'event-based dosing'. You should only take PrEP this way if your only risk is from having anal sex and you’re not on gender-affirming hormones. With on-demand dosing, PrEP is taken around the time you have sex: two tablets two to 24 hours before sex, one tablet 24 hours after sex and a further tablet 48 hours after sex.
If you’re an AMAB non-binary person who isn’t taking gender-affirming hormone treatment and only having anal sex, then you can take PrEP on demand.
PrEP is very safe and serious side effects are very rare. A few people experience nausea, headaches or tiredness which tend to only last a few days or weeks.
The drugs most commonly used for PrEP are emtricitabine and tenofovir (which are combined in a single tablet).
Before taking PrEP
Before taking PrEP, have a full sexual health screen at a local clinic, including an HIV test and a test for kidney function.
While taking PrEP, test for HIV and all other STIs every three months.
Where to obtain PrEP
You can get PrEP for free on the NHS from a sexual health clinic.
PrEP can also be bought from a reliable source.
If you want to stop taking PrEP
If you want to stop taking PrEP for any reason and are taking it daily, you should continue taking it for seven days after sex. If you are taking ‘on-demand dosing’ you should continue taking PrEP for two days after the last time you have sex without a condom.
Get tested for HIV before you start taking PrEP again. If you have acquired HIV and begin taking PrEP, you may develop resistance to the drugs used for PrEP which could affect future treatment options.
If you're living with hepatitis B, be aware that PrEP can suppress the virus – you should always use daily dosing of PrEP and shouldn't stop taking PrEP until you've got advice from your doctor.
PEP (post-exposure prophylaxis for HIV) is a treatment that can stop an HIV infection after the virus has entered a person’s body (for example, if you’ve had sex and the condom fails). To work, PEP must be taken within 72 hours (three days), and ideally should be taken within 24 hours.
If you think you've been at risk of acquiring HIV, it might be worth accessing post-exposure prophylaxis (PEP).
You can access PEP from a sexual health clinic or A&E. Tell your doctor if you're taking any hormones and any other drugs or medications. There are very few interactions with oestrogen treatment.