Clinically reviewed by Dr. Ponlawat Pitsuwan, Physician, Doctor Bangkok. Last reviewed: July 2026
Daily PrEP means one tablet every day for continuous protection, while on-demand PrEP involves taking tablets around a specific planned exposure. Both are effective when taken correctly, though on-demand is not suitable for everyone. Which fits you depends on your pattern of risk and your health.
Once people decide they want PrEP, the next question is almost always how to take it. In my Bangkok clinic, expats and travellers frequently ask whether they really need a tablet every single day, or whether they can just take it around the times they need it. Both are valid options, but they suit different lives and different patterns of risk.
This article compares daily and on-demand dosing, explains the monitoring that comes with PrEP, and sets out how cost works so there are no surprises. It builds on our main PrEP and PEP in Bangkok page, which is the best place to start if PrEP is new to you.
Daily PrEP
Daily PrEP means taking one tablet at roughly the same time every day. It provides steady, continuous protection, so you are covered regardless of when a possible exposure occurs. This makes it a good fit for people with regular sexual activity, an unpredictable schedule, or simply a preference for not having to plan ahead.
Who daily suits
Daily dosing is the most widely used and the most broadly suitable approach. It is the recommended option for many people and, importantly, is the approach best supported for a wider range of situations. If you value simplicity and reliable, always-on protection, daily PrEP is usually the answer.
On-demand PrEP
On-demand PrEP, sometimes called event-based or 2-1-1 dosing, involves taking tablets around a specific planned exposure rather than every day: a dose in the hours before, then further doses on the following two days. It can suit people whose exposures are infrequent and who can plan ahead.
Important limits
On-demand dosing is not suitable for everyone. Its evidence is strongest for certain groups and it is generally not recommended in some situations, so it is essential to discuss it with a doctor rather than assume it applies to you. It also requires careful timing, which means it works best for people who can reliably plan around exposures. We will talk through whether it is appropriate for you at your consultation.
Which is right for you?
The best choice depends on how often and how predictably you have possible exposures, your health, and your own preference. Someone with frequent or spontaneous activity is usually better served by daily PrEP, while someone with occasional, plannable exposures might consider on-demand if a doctor agrees it is suitable. There is no single right answer, and it is a decision we make together.
Monitoring while on PrEP
Whichever dosing you use, PrEP comes with regular monitoring. Before starting, we confirm you are HIV-negative and check your kidney function and general health. While on PrEP, we repeat HIV testing, screen for other sexually transmitted infections and recheck kidney function, typically every few months.
This ongoing care is part of what makes PrEP safe and effective, and it is a chance to look after your wider sexual health too. If you would like broader screening alongside your PrEP reviews, our HIV testing in Bangkok page explains what is involved.
What does PrEP cost?
The cost of PrEP depends on the medication used, the dosing approach and the monitoring tests that come with it. Because these vary, we give you clear, itemised pricing at your consultation before you commit to anything. You are always welcome to ask about cost openly, and we will make sure you understand what each part covers.
Some people find on-demand dosing uses fewer tablets over time if their exposures are infrequent, while others prefer the predictability of a daily routine. We can help you weigh the practical and financial sides together.
When to see a doctor
See a doctor to start PrEP if you have an ongoing or foreseeable risk and want dependable protection, and see one for your routine reviews if you are already taking it, as skipping monitoring is not safe. You should seek care promptly if you think you may have had a possible exposure that PrEP did not cover, for example if you missed doses, and urgently if that exposure was within the last 72 hours, as emergency PEP may be needed instead.
Not sure whether daily or on-demand PrEP is right for you? Our walk-in clinic in Sukhumvit offers confidential PrEP consultations with clear pricing and ongoing monitoring. Read our full PrEP and PEP guide or contact us to book.
Frequently asked questions
Is daily or on-demand PrEP more effective?
Both are effective when taken correctly. Daily dosing is the most broadly suitable and simplest to get right, while on-demand can work well for certain people who plan around exposures. The right choice depends on your situation, which we assess together.
What is 2-1-1 dosing?
It is a common name for on-demand PrEP: a dose before a planned exposure, followed by doses on the next two days. Because the timing matters, we go through exactly how to take it at your consultation.
Can anyone use on-demand PrEP?
No. On-demand dosing is not suitable for everyone, and it is generally not recommended in some situations. This is why it should only be used after discussing it with a doctor who can advise whether it fits you.
How often do I need check-ups on PrEP?
Monitoring is typically every few months and includes HIV testing, screening for other STIs and a kidney check. These reviews keep PrEP safe and effective, and we schedule them with you.
How much does PrEP cost in Bangkok?
It depends on the medication, the dosing approach and the monitoring involved. We provide clear pricing at your consultation before you start, so you know exactly what to expect.
Can I switch between daily and on-demand?
Often, yes, if your circumstances change and a doctor agrees the new approach suits you. We can review your dosing at your regular check-ups and adjust it as your needs evolve.
Dr. Ponlawat Pitsuwan
Physician, Doctor Bangkok
Dr. Ponlawat is a physician at Doctor Bangkok, a private medical clinic in central Bangkok. He helps expats and travellers choose and manage the PrEP approach that fits their lives, with clear pricing, regular monitoring and confidential care.
Dr. Ponlawat Pitsuwan is a physician at Doctor Bangkok, a private clinic in central Bangkok. He sees expats, residents, and medical tourists for general medicine, wellness consultations, and IV therapy. His focus is straightforward, evidence-based care delivered in plain language.