The Basics of PrEP

Disclaimer: I am not a medical professional. This article is intended to be read as a quick guide - consult with a medical professional before deciding to take PrEP.

What is PrEP?

PrEP is a medication which, when taken correctly, is a means of reducing the chances of getting HIV.

It stands for Pre-Exposure Prophylaxis, which means treatment taken before risk of exposure. It is different to PEP or PEPSE, which is a course of medication taken post-risk of exposure to help prevent HIV.

PrEP does not protect against anything other than HIV and therefore is not an alternative to condoms


Who is PrEP for?

PrEP is a great idea for people who are HIV negative and have sex in a variety of situations where condoms are not easily or always used.
- Terrence Higgins Trust


How should I take PrEP?

There are four ways to take PrEP:


This option is for where you might be in a position when you don't know if you might have sex. You should try and take it at the same time of day so that you get into a routine, but it doesn't matter if you take it a few hours early or late. While it's safest to take it every day, by using this method you could miss a day occasionally but still be protected.

Event-based / On-demand dosing

This is only suitable for anal sex, not vaginal/front hole sex. It is important not to miss any dose of PrEP if you take PrEP in this way.

If you know at least 24 hours in advance that you're going to be having condomless sex, you should: take 2 pills 2-24 hours before sex; 1 pill 24 hours later and another pill 24 hours after that. If you continue to have sex then you should take PrEP at the same time every day until you have 2 sex-free days.

4 pills per week (Ts and Ss)

Again, only suitable for anal sex. You should start by taking PrEP every day for a week (7 days).

You take 4 PrEP pills a week on Tuesday, Thursday, Saturday and Sunday. This means that there is still enough PrEP in your system through the week. It's useful for when you only have sex once or twice a month and can save money if you choose to buy PrEP privately.

Holiday-based dosing

You should start taking PrEP every day a week before you go on holiday, every day while you're away and for another week after you come back. 7-holiday-7.


How do I get PrEP?

It depends where you are in the UK:

  • In Scotland, you can go to your local sexual health clinic to request a prescription if you meet certain criteria (for more details visit PrEP Scotland)
  • In Wales, you can participate in a 3-year trial which has unlimited places if you meet certain criteria (for more details visit PrEPared in Wales)
  • In England, the NHS has started the PrEP IMPACT Trial, which has 10,000 places. Places are limited per sexual health clinic and you must meet certain criteria (for more details visit PrEP IMPACT Trial)
  • In Northern Ireland, there is a project for offering PrEP - just go to your local sexual health clinic and ask for an initial consultation and assessment (for more details visit I Want PrEP Now)

There's tons of information around, like I Want PrEP Now from the Terrance Higgins Trust.

Have you taken PrEP or got any questions? Ask in this thread.