Tadalafil and sildenafil are the two best-known get more info treatments for erectile dysfunction. Both have a long track record, and both are sold as cheaper generics. The main question is usually not which one is "better", but which one suits the way you live.
Sildenafil is normally taken about an hour before sex and lasts around four to five hours. A high-fat meal can delay the effect. Generic tadalafil, on the other hand, can work for up to 36 hours, and food makes little difference. Some men also take a low daily dose of tadalafil so they never need to time a tablet.
To compare the two in more detail, see this plain-English guide explains the differences step by step.
A few safety points: never take either medicine with nitrate tablets or sprays for chest pain or with "poppers". Tell your doctor about any other medicines you take. The usual side effects are headache, flushing, a blocked nose and indigestion. Seek medical help straight away for an erection lasting more than four hours or sudden changes in vision.
Strength matters too. The licensed doses are 25, 50 or 100 mg for sildenafil and 2.5 to 20 mg for tadalafil. Higher-strength tablets do not bring better results, but they do raise the risk of side effects. Stick to the dose on your prescription.
If you choose to buy generic sildenafil or tadalafil online, check the strength on the pack and keep the leaflet. A valid prescription is required for every order of a prescription medicine. More practical tips are on this page.
This is general information, not medical advice. Speak to your doctor or pharmacist before starting any medicine.