Medically reviewed guide · Last updated: 23 June 2026 · Reading time: approx. 13 min

Erectile dysfunction pills compared: a serious check

Hardly any health topic is so surrounded by advertising, spam and dubious online shops as erectile dysfunction pills. Anyone who searches for a comparison quickly and often lands at questionable offers that allegedly sell prescription medicines without a prescription. This guide counters this with a factual, serious overview: it explains how the four approved active ingredients sildenafil, tadalafil, vardenafil and avanafil work, how they differ and which safety rules absolutely must be observed. At the centre are not purchase incentives but reliable, factually checked information and clear warnings. Important beforehand: this guide does not replace medical advice, recommends no particular preparation and deliberately contains no dosage details. Erectile dysfunction pills are prescription only and belong in medical hands. The aim of this guide is to give a reliable orientation in a field that is dominated online like hardly any other by dubious providers, and thus to create a factual basis for the conversation in the medical practice.

How PDE5 inhibitors work

The common erectile dysfunction pills all belong to the same group of active ingredients, the so-called PDE5 inhibitors. The name derives from the enzyme they block, the phosphodiesterase of type 5. They block an enzyme called phosphodiesterase 5, which normally breaks down a messenger substance responsible for the relaxation of the blood vessels. If this enzyme is inhibited, the vessels in the penis can during sexual arousal widen better, the blood flow is promoted and an erection is easier. Decisive here is an often misunderstood point: these agents work exclusively with sexual stimulation. They do not trigger an erection at the push of a button but support the natural process. Without corresponding arousal, the effect is absent. This basic principle also explains why the agents are no replacement for desire or arousal but merely improve the physical preconditions for an erection when the sexual stimulation is present.

With this PDE5 inhibitors treat the symptom, that is the erectile dysfunction, but not its cause. An erectile dysfunction can have many reasons, from cardiovascular diseases over diabetes and hormonal disorders to psychological burdens. Exactly for this reason a medical clarification is so important: it can uncover possible underlying diseases that should be treated. An erectile dysfunction is moreover considered a possible early warning sign for cardiovascular problems, which is why it should not be concealed out of shame but discussed medically. Since the fine vessels in the penis react especially sensitively to circulation disorders, problems there can often show already before complaints arise elsewhere. The agents themselves are an effective, well-studied help but do not replace the search for the cause. Anyone who covers up an erectile dysfunction with a tablet alone, without having the underlying reasons clarified, possibly misses the chance to recognise and treat a serious underlying disease early.

The four active ingredients compared

In their basic effectiveness the four approved PDE5 inhibitors are very similar according to studies. In direct comparison studies no large differences in the success rate showed, which is why the selection in practice depends above all on the further properties. The most important differences lie in the pharmacokinetics, that is in how quickly the effect sets in and how long it lasts. Sildenafil, the oldest and best-studied active ingredient, mostly works after about 30 to 60 minutes and over a few hours. It was the first approved representative of this group and is, through its long-standing use, particularly well researched. Vardenafil behaves similarly. Avanafil is the newest representative and is considered especially fast, with a possible onset already after about 15 to 30 minutes. With this it is especially suitable for users who wish for a fast and well plannable onset. With these three active ingredients a fat-rich meal can delay the onset. Anyone who wants a most reliable and plannable effect should take this into account when eating, which is likewise a point that is best clarified in the medical conversation or with the advice in the pharmacy.

A special role is played by tadalafil. It needs longer until the full effect but works by far the longest, up to around 36 hours. This long duration of action has earned it the nickname weekend pill, since it allows a greater temporal independence from the intake. For some couples this is an advantage, because the intake then does not have to be closely coordinated with the sexual intercourse. Tadalafil can in a low dosage also be prescribed for daily intake. In this case the effect builds up over several days and allows a greater temporal independence, since the intake is then no longer directly coupled to a particular point in time. Which active ingredient fits best is not a question of good or bad but of the personal needs, pre-existing conditions and accompanying medicines. Exactly this individual weighing belongs in the medical practice and not in an anonymous online shop. Some men moreover react better or more tolerably to one active ingredient than to another, so that it can quite well happen that after medical consultation a second active ingredient is tried out if the first does not fit optimally.

Side effects and for whom caution applies

Like all effective medicines, PDE5 inhibitors too can have side effects, which are quite similar across all four active ingredients. How strongly they occur is different from person to person. Very frequent are headaches, frequent are facial flushing, a feeling of warmth, a stuffy nose, dizziness or light stomach complaints. These complaints are mostly mild and temporary. They arise because PDE5 inhibitors widen not only the vessels in the penis but to a lesser degree also other blood vessels in the body, which explains for example the facial flushing or the stuffy nose. There are, however, small differences between the active ingredients: under sildenafil and vardenafil, temporary visual disturbances occur somewhat more frequently, for example blurred vision or a changed colour perception, while under tadalafil muscle and back pain are reported somewhat more frequently.

Beyond the nitrate combination there are further situations in which special caution applies or PDE5 inhibitors do not come into question. To this belong certain severe cardiovascular diseases, with which sexual activity is generally advised against, as well as some eye diseases. A severe liver or kidney function disorder as well as a recently suffered heart attack or stroke too can speak against the use or require a particularly careful medical weighing. Since many men with erectile dysfunction carry cardiovascular risks anyway, the medical placement of the complaints is especially important. Very rarely more serious events have been described, whose causal connection with the agents is, however, hard to assess. With persistent, unusual or severe complaints, medical advice should be obtained in any case. A rare but important warning sign is a painful permanent erection that lasts longer than a few hours: it is a medical emergency and must be treated medically immediately, since otherwise lasting damage can threaten.

The safe way and possible alternatives

The only safe way to an erectile dysfunction pill leads via the medical practice. There possible causes and risks are clarified, interactions checked and the fitting active ingredient selected together. Many men experience the first step, addressing the topic at all, as the biggest hurdle, but in practice the erectile dysfunction is a frequent and everyday concern that is treated there in a routine and confidential way. PDE5 inhibitors are thereby not the only option. An erectile dysfunction can often also be positively influenced via the lifestyle, for example through more exercise, stopping smoking, less alcohol and the reduction of overweight. These measures do not work overnight but improve in the long term the vascular health and with it frequently also the erectile capacity. The treatment of underlying diseases such as diabetes or high blood pressure plays an important role too, and with psychological causes a psychological support can help. Which solution fits is always individual. In many cases a combination is sensible: a medicine can help in the short term, while at the same time work is done on the causes, for example through more exercise or the better adjustment of an underlying disease. This way the erectile dysfunction is not only covered up but tackled in the long term.

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In sum it applies: the four erectile dysfunction pills sildenafil, tadalafil, vardenafil and avanafil are effective and well-studied agents against erectile dysfunction that differ above all in onset and duration of action. The best agent does not exist across the board but always only fitting to the respective individual situation. Decisive are the medical clarification, the strict observance of the contraindications, first of all the absolute nitrate ban, and the conscious doing-without of dubious online offers. This way a topic flooded by spam becomes a factual, safe decision. Anyone who informs themselves well and goes the way via the medical practice and an approved pharmacy can safely use the effectiveness of these medicines and at the same time avoids the considerable risks connected with fake preparations and dubious online sources.