Risks and Side Effects of DoxyPEP

Given the high effectiveness of DoxyPEP, it is all the more important to properly weigh up the risks and side effects. DoxyPEP is a new method for the prevention of sexually transmitted infections (STIs), but should only be used after certain risk events (→ read more about “DoxyPEP: Potential and Target Group”). Let's take a deeper look into the topic of DoxyPEP and its risks and side effects.
February 19, 2024

Disclaimer: Please note that this information is provided for general informational purposes only and is not a substitute for professional medical advice or consultation. Each individual's health situation is unique, and it is important to seek the guidance of a qualified healthcare provider for any questions or decisions regarding the use of DoxyPEP or any other medical treatments. If you are considering DoxyPEP for yourself, we recommend contacting your health practitioner or finding one through Every Health for personalized advice and care.

The experience base of doxycycline as an antimicrobial substance is huge; we have been using this antimicrobial substance in the treatment of humans and animals for over 60 years.

Overall Tolerance and Drug Interactions

DoxyPEP is known for its general tolerability, with very few negative interactions reported with other prescription drugs. But still those interactions can be quite serious in rare cases, there for we highly recommend to check for interactions with your general practitioner or a doctor found through Every Health. Long-term use of doxycycline, the key component of DoxyPEP, has been well documented for various medical purposes, such as acne treatment and malaria prophylaxis, but we are still learning about continuous intermittent treatment where we have limited data on developent of possible bacterial resistances that could make treatment of STI and other bacterial infections more difficult. We are also still learning about the effect on the microbiota, which could affect other health conditions. More results are expected soon and we will keep you updated as soon as we know more!

Common Side Effects and Minimization Strategies

Some individuals may experience side effects when taking DoxyPEP, including feelings of nausea, headaches, and gastrointestinal issues. To minimize these risks, it is recommended to take doxycycline with a glass of water, not on an empty stomach, and to remain upright for at least 30 minutes after ingestion to prevent reflux. Because of some rare possible side effects concerning the blood and kidney function you should consider some laboratory Monitoring at least once a year. Any side effect that leaves you concerned should be evaluated by a doctor.

Interaction with Calcium/Magnesium/Aluminum-Rich Substances

Avoiding supplements or foods rich in calcium, magnesium, or aluminum within 4 hours of taking DoxyPEP is crucial, as these substances can weaken the effectiveness of doxycycline. This includes common items like dairy products, stomach remedies, fitness drinks, and electrolytes. Non-absorbable complexes are formed and neither the drug nor the element reaches the bloodstream.

Increased Sensitivity to Sunlight

Doxycycline, as a tetracycline antibiotic, can increase skin sensitivity to sunlight. Users are advised to wear sunscreen with a sufficient Sun Protection Factor (SPF) when using DoxyPEP to minimize the risk of sunburn and other skin-related issues.

Gut Microbiome Considerations

Antibiotic use, including doxycycline in DoxyPEP, is associated with potential disruptions to the gut microbiome. While there is currently inconclusive data if and how much DoxyPEP influences healthy gut bacteria, users may consider taking proactive steps to preserve gut health. This can include incorporating pre- and pro- and postbiotics into their routine. There are some clinical studies on the way and we expect further gain of knowledge soon.

We should never forget that doxycycline is a highly active antimicrobial substance which, although it is not very noticeable when ingested, should be used with caution. We should always keep in mind its great importance for humanity in many areas.

Resistance for Antibiotics

DoxyPEP raises questions about antibiotic resistance, particularly concerning gonorrhea. While doxycycline has not shown resistance in chlamydia or syphilis, gonorrhea presents a different scenario. Ongoing studies like the DoxyPEP study are crucial for understanding if DoxyPEP influences resistance in gonorrhea. These efforts are key to ensuring that DoxyPEP remains a valuable tool in STI prevention while managing the potential for antibiotic resistance. The balance between the benefits of DoxyPEP in preventing STIs and the risk of increased resistance is a focus of current research.

Potential for Yeast Infections

The reduction of bacteria in and on the body, a common effect of antibiotic use, can sometimes lead to yeast infections, Individuals using DoxyPEP should be aware of this possibility and seek over-the-counter anti-fungal remedies if they experience such infections.

Consultation with Healthcare Professionals

Individual responses to medications can vary, and it's crucial for users to consult with healthcare professionals if they have concerns or experience any unusual symptoms. Healthcare providers can provide personalized guidance based on an individual's health history and specific circumstances.

Pregnancy and Breastfeeding

If there is a risk of pregnancy, you should not take DoxyPEP as it can damage the bones and teeth of the unborn child. If you later find out that you were already pregnant while taking DoxyPEP, don’t panic. It is unlikely that doxycycline will harm your unborn within the first 3 months of pregnancy. No DoxyPEP should be taken while breastfeeding.


Understanding the potential risks and side effects of DoxyPEP is essential for users seeking effective STI prevention. While the medication is generally well-tolerated, being aware of possible side effects and taking proactive steps to minimize risks ensures a more positive and informed experience. As with any medication, open communication with healthcare professionals enhances the overall safety and effectiveness of DoxyPEP use in maintaining sexual health.