When it comes to protection during sex, most people think of condoms first. But the toolkit for your sexual health has grown a lot bigger. Two methods stand out in particular: PrEP and Doxy-PEP. On their own, both are strong. Together, they create protection that leaves barely any gaps.

PrEP: your shield against HIV

PrEP stands for pre-exposure prophylaxis and is one of the most effective ways to prevent an HIV infection. Put simply, you take a tablet regularly that blocks the virus before it can establish itself in the body. When used correctly, PrEP lowers the risk of HIV transmission by over 99 percent.

The catch: PrEP only protects against HIV. It does nothing against bacterial sexually transmitted infections like chlamydia or syphilis. So if you often have sex without a condom, you can still get infected despite PrEP. This is exactly where Doxy-PEP comes in.

Doxy-PEP: the backup against bacterial STIs

Doxy-PEP is a post-exposure prophylaxis that comes into play after sex. The principle is refreshingly simple: taken within a maximum of 72 hours after contact, it inhibits the multiplication of certain bacteria, so that in the best case an infection does not develop in the first place.

The data is convincing. In a large analysis from San Francisco, chlamydia cases dropped by 67 percent and syphilis cases by as much as 78 percent (Scott H et al., CROI 2024). So while PrEP protects against HIV over the long term, Doxy-PEP specifically stands in the way of chlamydia and syphilis.

Why the combination is so strong

On their own, each method covers its own area. Together, they close the gap almost completely:

Covered all around: PrEP minimises the HIV risk, Doxy-PEP lowers the danger of bacterial STIs. That way you are guarded against several risks at once, not just one.

Fewer infections, fewer treatments: Every infection you prevent protects not only you, but also slows the spread of STIs overall.

More freedom, less overthinking: If you have frequently changing sexual partners, you win back a sense of security and can simply enjoy sex again.

No one necessarily needs both strategies at the same time. But if you regularly have higher-risk contacts, the combination of PrEP and Doxy-PEP can be a really worthwhile addition.

Is the combination right for me?

That depends on your personal risk. People who can especially benefit are:

• People who already use PrEP and want extra protection against bacterial STIs.
• People who often have sex without a condom or have changing partners.
• Anyone who has had an STI before and wants to keep the risk of another infection low.

Whether the combination is medically right for you is something only a medical assessment can settle in the end. With pre-existing conditions or drug intolerances, that check is especially important. And as uncomplicated as both methods are, they only work if you use them reliably: regularly with PrEP, in a targeted way after sex with Doxy-PEP. And no matter how good your protection is, regular STI testing stays part of good prevention.

What about side effects?

The vast majority of people tolerate PrEP and Doxy-PEP well. If they occur at all, side effects are usually mild: minor gastrointestinal issues like nausea or diarrhoea, sometimes headaches or fatigue, and in rare cases skin reactions. Regular medical check-ups help to catch these early and adjust the treatment to you.

One point that belongs here: antibiotics should be used responsibly, with resistance in mind. For chlamydia and syphilis, no relevant resistance to the standard therapy has been observed so far, and under medical guidance the risk stays manageable. That is why Doxy-PEP belongs in expert hands and not in self-medication.

The takeaway: protection that does more together

PrEP and Doxy-PEP are not competitors, they are a team. One method takes care of HIV, the other of chlamydia and syphilis. If you regularly have sex without a condom or have frequently changing partners, this dual strategy gives you protection that leaves barely any gaps. After all, sexual health is not a luxury, it is a piece of quality of life. And it is allowed to feel good and safe.