01 / ERECTION PROBLEMS
Sildenafil
The active ingredient in Viagra and several other medicines for erectile dysfunction. Learn about its effects during sexual stimulation, precautions and possible side effects.
The 123Kamagra knowledge centre
Erection problems and sexual health: understand your options
Wondering how sildenafil, tadalafil or dapoxetine works? Or looking for a straightforward answer about erections and sex? Start here. We explain the essentials in everyday language, without making an already personal subject harder to talk about.
Active ingredientsEffects and side effectsSexual healthSafer use
Start with the basics
Which ingredient would you like to understand?
Medicines may look similar, but their effects and uses can differ. Choose a topic, then take your time with the details.
The in-depth articles linked below are currently in Dutch. Our English FAQ provides a useful starting point.
02 / LONGER-LASTING EFFECT
Tadalafil
The active ingredient in Cialis. Its effect can last longer than sildenafil’s. What does that mean for use, interactions and side effects?
03 / PREMATURE EJACULATION
Dapoxetine
Used for certain forms of premature ejaculation. It is not a medicine for getting an erection. Read about its purpose and when to seek medical advice.
04 / BRAND AND INGREDIENT
Kamagra
Kamagra contains sildenafil. We explain why a brand name, an active ingredient and a medicine’s authorisation and safety are different things.
05 / WOMEN’S HEALTH
Women’s sexual health
What do we know about sildenafil in women? Claims about desire and arousal are not always supported by scientific evidence. Explore the explanations and limitations.
06 / COMPARING OPTIONS
Sildenafil or tadalafil?
A comparison of duration, use and side effects. A helpful starting point for a conversation with your GP about the options.
Questions we often hear
From erection problems to medicine safety
You may be looking for an answer rather than a particular medicine. These Dutch-language articles can help you explore further.
Making sense of the information
Understand first. Decide afterwards.
A product name tells you only part of the story. Pay attention to the active ingredient, the risks and whether a medicine is suitable for your health.
STEP 1
Start with your question
Is it about getting an erection, another sexual concern or something you have read? Similar symptoms can have different causes.
STEP 2
Read the precautions too
Check side effects, medicine interactions and existing health conditions. Never combine PDE5 inhibitors with nitrates or poppers.
STEP 3
Ask a professional when you are unsure
Sildenafil and tadalafil are prescription medicines. Your doctor or pharmacist can help assess whether treatment is suitable.
Independent information
Read beyond our own articles
We encourage you to consult independent medicine information and check effects, side effects and official authorisations. The following sources are in Dutch.
Important: This knowledge centre provides general information, not a personal medical assessment, diagnosis or prescription. Speak to your GP or pharmacist about symptoms, side effects or questions about your treatment.
Still have a question?
Let’s point you in the right direction.
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Editor: Rogier · Dutch source last updated: 16 October 2026 · English version: 4 November 2026
