PrEP and PEP on Koh Samui: The Difference, and Why the Clock Matters

PrEP and PEP are two of the most effective tools we have against HIV — and they are widely misunderstood. The names look almost identical, but they do different jobs, and with one of them timing is everything. Here is the plain version, without judgement.

PEP — the emergency option, after exposure

PEP (post-exposure prophylaxis) is a course of antiretroviral medication you take after a possible exposure to HIV — a broken condom, a needle-stick, or sex you are worried about. It is a 28-day course, and it can stop an infection from ever taking hold.

The catch is time. PEP has to be started within 72 hours (3 days) of the exposure to work — and the sooner the better, ideally within 24 hours. After 72 hours it is no longer recommended because it is unlikely to prevent infection. If you think you may have been exposed, this is not a wait-and-see situation. Come in, or message us, today.

PrEP — the everyday option, before exposure

PrEP (pre-exposure prophylaxis) is a pill taken by HIV-negative people who are at ongoing risk, to stop them getting HIV in the first place. Taken correctly, it is more than 99% effective at preventing HIV transmission through sex. Think of PEP as the fire extinguisher and PrEP as not leaving the stove on.

Which one is for me?

• A one-off worry after a specific incident, within the last 3 days → PEP, urgently.
• Ongoing risk you want to stay ahead of → PrEP, as a routine.
• Not sure → talk to us confidentially; we will help you work it out.

How it works at the clinic

For PEP, we assess you quickly, run a baseline HIV test, and start the course the same day where appropriate — the clock is the priority. For PrEP, we do a short consultation and baseline bloods (HIV and kidney function), then start you on it with simple follow-up checks. Everything is private and non-judgemental. Nothing about your visit is shared.

Frequently asked questions

• How fast do I need to start PEP? Within 72 hours of exposure, ideally within 24. Sooner is always better.
• How long is the PEP course? 28 days, taken every day without missing doses.
• How effective is PrEP? More than 99% at preventing sexual HIV transmission when taken correctly.
• Is it confidential? Completely. Sexual-health care here is private and without judgement.
• Do I need an appointment? For PEP, come straight in or message us — do not wait for a slot. PrEP can be booked normally.

“With PEP, the single most important factor is how fast you start. If in doubt, treat it as urgent.”— Samui Home Clinic