The 4 ways to take PrEP.

How you take your PrEP depends on:

  • how far in advance you plan on having sex
  • how regularly you have sex.

It does not necessarily depend on how much sex you have.

Check for other interactions with other drugs here.

Switching between dosing options

There are slightly different recommendations for anal sex and vaginal or frontal sex.

We recommend daily PrEP (including holiday PrEP) for all trans people using hormone treatment as we don’t have sufficient data to support other dosing options.

Switching between dosing options to match your sexual activity and patterns is totally OK. You can adjust your PrEP regime to best suit you as your situation changes.

Remember that:

  • On Demand dosing (or Event Based Dosing) and 4 pills per week are methods suitable only for anal sex.
  • Daily PrEP and Holiday PrEP are the only methods of taking PrEP that are suitable for both anal and vaginal or frontal sex.

We know that a minimum of 6 pills per week is required for adequate protection for vaginal or frontal sex.

Daily PrEP (1 pill per day) routine

The lead-in time for daily PrEP is 7 days. It’s suitable for both anal and vaginal or frontal sex.

Daily PrEP is best taken at the same time each day so it becomes part of your routine, but a few hours late or early is fine.

You can keep your PrEP next to your toothbrush and tooth paste and take your pill each morning after cleaning your teeth. Little things like this will help you remember to take your PrEP.

You can take PrEP with or without food, and at any time of the day.

One of the benefits of taking daily PrEP is that you can miss a pill from time to time and still have adequate protection.

Peace of mind

PrEP is an ‘opt in’ treatment – it doesn’t have to be forever.

Be kind to yourself and try to remember to take your pill every day.

Your peace of mind and release from the stress and anxiety that come with trying to stay HIV negative are also hugely important.

It’s not just about sex, it’s about your head and your heart too.

On Demand PrEP or Event Based Dosing (EBD)

This dosing option is only suitable for anal sex, not vaginal or frontal sex.

If you’re using On Demand it’s really important not to miss any doses.

On Demand dosing is as effective as daily PrEP for anal sex.

If you know that you might have condomless sex 24 hours in advance:

  • take 2 pills 2 – 24 hours before sex
  • take 1 pill 24 hours later
  • take 1 more pill 24 hours after that

If you’re having sex for an extended period of time, perhaps over a few days or a weekend, continue to take a pill every 24 hours until you have 2 sex-free days.

This option is not recommended if you have an active hepatitis B infection. The drugs in PrEP also supress the hepatitis B virus and so starting and stopping PrEP can cause viral flare-ups and liver inflammation.

4 pills per week — also known as ‘the Ts and Ss’

This dosing option is only suitable for anal sex, not vaginal or frontal sex.

We recommend daily dosing for 7 days, then dropping down to 4 pills per week.

4 pills per week usually involves taking a pill on Tuesday, Thursday, Saturday and Sunday — that’s why it’s called ‘the Ts and Ss’.

This option has several benefits:

  • If you only have sex once or twice a month, you might not want to take a pill every day. You might feel it’s more pills than you need to protect you for these 1 or 2 events.
  • 4 pills per week will maintain a good baseline of drug in your system and you can choose to move up to 7 pills per week when you know you’re in a more sexually active period.
  • Some people using PrEP On Demand find that they might be taking 4 pills per week most weeks of the month and so opt for structuring this into the Ts and Ss instead.
  • It costs you less because it reduces the number of pills you take each month by almost half — which reduces the cost per month by almost half too.

Though these dosing options don’t seem to follow a simple rule, they are based on study data.

Holiday PrEP

Consider Holiday PrEP before a pre-planned block of time when your risk of exposure to HIV will be higher due to:

  • an increased number of partners of unknown HIV status
  • situations where condoms are not easily or always used
  • where substances might be used
  • having sex while travelling to a country with a high HIV prevalence.

Holiday PrEP is suitable for both anal and vaginal or frontal sex.

Based on a 7-day period (or holiday) we recommend 7-7-7:

  • 7 days daily dosing before the period
  • 7 days daily dosing during the period (or for as long as the specific period lasts)
  • 7 days daily dosing after the period.

We recommend 7 days of PrEP before and after your last sexual encounter for several reasons:

  • 7 days lead-in provides adequate levels for both anal and vaginal or frontal sex.
  • If you’re planning PrEP around a holiday or working trip away and you experience any mild side effects (most people do not experience any side effects) then most of these should have subsided within a week, in time for the pre-planned block of time.

PrEP tool

If you’re already taking PrEP, take our PrEP quiz to find out if you’re doing it correctly.