Sildenafil and tadalafil are the two most widely prescribed treatments for erectile dysfunction. Both work well for most men, and both are sold as lower-cost generics. The question that matters is often not which one is "better", but which one suits the way you live.
Generic sildenafil is usually taken about an hour before sex and works for four to five hours. A high-fat meal can slow it down. Tadalafil, on the other hand, can work for up to 36 hours, and food has little effect. Plenty of men also take a low daily dose of tadalafil so they do not have to plan ahead.
If you want a simple comparison, read the full guide here walks through timing, food and side effects.
A few safety points: never take either medicine with nitrate tablets or here sprays for chest pain or with "poppers". Let your doctor know about any blood pressure tablets. Common side effects are headache, flushing, a blocked nose and indigestion. Get urgent help for an erection lasting more than four hours or sudden changes in vision.
More is not always better. The licensed doses are 25, 50 or 100 mg for sildenafil and 2.5 to 20 mg for tadalafil. Higher-strength tablets do not reliably work better, but they do make side effects more likely. Stick to the dose on your prescription.
When you buy medicine online, make sure the strength matches your prescription and read the patient leaflet. A valid prescription is required for every order of a prescription medicine. You can read more on this page.
This is general information, not medical advice. Speak to your doctor or pharmacist before starting any medicine.