Tadalafil dosage: how much, and how often

Tadalafil comes in four strengths across two different regimens, which is why the dosage question gets confusing.

Here's what each strength is for, how often each can be taken, and the situations where tadalafil isn't suitable at any dose.

Tadalafil doses

Which one suits you depends on how often you expect to need it and how you'd rather take it, and your doctor will factor in your health and anything else you're taking.

Take tadalafil no more than once in 24 hours

This matters because the effect lasts a long time. Tadalafil can stay active for up to 36 hours, which means the effect of yesterday's tablet may still be there today.

Don't take a second dose because the first seems to have worn off. If 20mg isn't working, that's a conversation with your doctor, not a reason to take more.

Never take tadalafil and Tadalafil Daily together, or tadalafil alongside sildenafil or another PDE5 inhibitor.

Daily or as needed?

This is the real decision, and it's about how you want it to fit rather than how well it works.

Tadalafil, taken when needed: One tablet around 30 minutes before sex. The effect lasts up to 36 hours, so it doesn't need precise timing the way some treatments do. It does mean thinking about it in advance.¹

Tadalafil Daily: A lower dose every day, keeping a steady level in your system, so there's nothing to plan and no tablet to take beforehand. It takes several days to build up, so it isn't something to start the night before.²

Neither is stronger than the other in any meaningful sense. The daily doses are lower precisely because they're taken continuously.

How long does tadalafil last?

Up to around 36 hours for the on-demand form, which is considerably longer than sildenafil.¹

During that window, you can get an erection when you're aroused, as you would without the tablet. Tadalafil doesn't produce one by itself, and the arousal still has to be there.

The long window is why some men prefer it. It takes the planning out of it.

When tadalafil isn't suitable

Some of these rule it out completely, whatever the dose.

Never take tadalafil if you take:^1-2

• Nitrates, usually prescribed for angina or chest pain. Together they can cause a dangerous drop in blood pressure.

• Amyl nitrite or other poppers, for the same reason.

• Riociguat, a medicine for high blood pressure in the lungs.

• Another erectile dysfunction tablet (a PDE5 inhibitor), including sildenafil or a second tadalafil product.

Tell your doctor before taking it if you have:

• A serious heart or liver condition

• Recently had a stroke or heart attack, or have low blood pressure

• A rare inherited eye condition such as retinitis pigmentosa

• Ever lost vision through non-arteritic anterior ischaemic optic neuropathy

This isn't a complete list, which is why tadalafil is prescription-only.

When to get urgent help

These are rare, but because tadalafil lasts a long time they can happen well after you've taken it, so it's worth knowing them. Get urgent help if:

• Your erection lasts more than four hours. Priapism is a surgical emergency and delay risks permanent damage.

• You suddenly lose vision or hearing.

• You have chest pain, and if you're prescribed nitrates for it, do not take them. Tell the clinician you've taken tadalafil.

The numan take

Tadalafil is 10mg or 20mg when needed, or 2.5mg to 5mg daily, and the choice between them is about how you want it to fit rather than how well it works.

The two things worth carrying away: no more than one dose in 24 hours, however long ago the last one feels, and nitrates rule it out completely.

Read the Patient Information Leaflet that comes with your tablets, because it's specific to the product you've been given.

References

^{1 Tadalafil 20mg film-coated tablets. Summary of Product Characteristics. Electronic Medicines Compendium. Accessed 13 October 2026. Available from: https://www.medicines.org.uk/emc/product/9363/smpc}

^{2 Tadalafil 5 mg film-coated tablets. Summary of Product Characteristics. Electronic Medicines Compendium. Accessed 13 October 2026. Available from: https://www.medicines.org.uk/emc/product/15261/smpc}