Sildenafil vs Tadalafil

Sildenafil and tadalafil are the two most widely used treatments for erectile dysfunction. They work in a similar way but differ in some important practical ways. Here’s a clear comparison to help you understand your options.

How both medicines work

Sildenafil and tadalafil belong to the same family of medicines, called PDE5 inhibitors. They treat erectile dysfunction by relaxing the blood vessels supplying the penis, which improves blood flow so you can get and keep an erection when sexually aroused. An important point that applies to both: they don’t create an erection on their own — you still need sexual stimulation for them to work. They also don’t increase desire; they address the physical mechanics of an erection. Because they work the same way, the choice between them usually comes down to practical differences — how quickly they act, how long they last, how they interact with food, and how you personally respond. Both are effective for the majority of men, and it’s common to try one and adjust if needed. Both are prescription medicines, so they should be taken after a consultation that checks they’re safe for you, particularly regarding your heart health and any other medicines.

The key differences at a glance

Duration: the biggest difference

The standout difference is how long each lasts. Sildenafil is effective for around 4 to 6 hours, which is plenty for a planned occasion. Tadalafil lasts much longer — up to 36 hours — which is why it’s sometimes called “the weekend pill.” For some men, that longer window removes the need to plan around a tablet and allows for spontaneity. Tadalafil can also be taken as a lower daily dose, so it’s always working in the background. Neither approach is better in the abstract; it depends on what fits your life.

Onset and food

Both typically start working within 30 to 60 minutes. The practical difference is food: sildenafil works best on an empty stomach, and a heavy or fatty meal can delay or blunt its effect, so it’s best taken a little before eating or well after. Tadalafil is less affected by food, so timing around meals matters less. If you like to enjoy a dinner before intimacy, that can tip the balance towards tadalafil.

Side effects

Because they work the same way, the side effects are broadly similar and usually mild, including:

• Headache
• Facial flushing
• Indigestion or stomach upset
• A blocked or runny nose

Some side effects relate to duration — for example, any that occur with tadalafil may last a little longer simply because the medicine itself does. Back or muscle aches are reported slightly more with tadalafil. Most men tolerate both well.

Safety: important for both

Both medicines share the same key safety rules:

• Never take them with nitrate medicines (used for chest pain/angina) — the combination can cause a dangerous drop in blood pressure.
• Use caution with certain heart conditions and some other medicines (including alpha-blockers).
• Seek urgent help for a painful erection lasting more than a few hours, or sudden changes in vision or hearing (both rare).

This is precisely why a prescriber reviews your health before supplying either, rather than buying from an unregulated source — the MHRA warns that ED medicines from illegitimate sellers can be fake or unsafe.

Which should you choose?

There’s no single winner. As a rough guide:

• Prefer sildenafil if you’re happy to plan around a tablet and want a well-established, as-needed option.
• Prefer tadalafil if you value spontaneity, dislike planning around food, or like the idea of a low daily dose.

Many men try one and switch if it doesn’t suit them — finding the right medicine and dose can take a couple of attempts.

Getting a prescription safely

The right choice is best made with a clinician who knows your health. You can complete a confidential ed consultation online uk with a GPhC-registered prescriber, or visit our Sheffield men’s health clinic in person. For background on why ED happens, see our guide to the causes of erectile dysfunction.