Tadalafil Dosage: Finding the Right Dose and Timing
A pharmacist's guide to tadalafil doses, from 2.5mg daily to 20mg on-demand, covering timing, missed doses, and what changes how it works.
Written and medically reviewed by:
Key Takeaways
Tadalafil comes in four UK doses: 10mg or 20mg on-demand, and 2.5mg or 5mg taken daily. Most people start on 10mg on-demand or 5mg daily, then adjust up or down based on effect and side effects.
The short answer#
Tadalafil comes in four strengths in the UK. For daily use, that's 2.5mg or 5mg. For on-demand use, it's 10mg or 20mg. Most people new to tadalafil start on 10mg on-demand, or 5mg daily if they'd rather not think about timing at all.
Your prescriber will help you pick a starting point based on your health, how often you're sexually active, and whether you've tried other erectile dysfunction (ED) treatments before.
Daily or on-demand: how the doses differ#
Daily tadalafil (2.5mg or 5mg) is taken at roughly the same time each day. It builds up to a steady level in your blood after about 5 days of regular dosing. Once you're at that steady level, you can get an erection whenever you're aroused, without planning ahead.
On-demand tadalafil (10mg or 20mg) is taken as one dose before sex. It works for up to 36 hours, so there's some flexibility, but you still need to take it in advance rather than in the moment.
Tadalafil 5mg daily is also licensed in the UK for benign prostatic hyperplasia (BPH), an enlarged prostate that causes urinary symptoms. The dose is the same whether it's being used for ED, BPH, or both together.
Not sure which treatment is right for you?
Working out your starting dose#
A sensible starting point looks like this. Try 10mg on-demand, or 5mg daily, if you're new to tadalafil.
If 10mg works but causes side effects, step down to 5mg on-demand or 2.5mg daily. If 10mg doesn't work after a few honest attempts, your prescriber may move you up to 20mg on-demand.
Daily 5mg suits men having sex several times a week who want steady cover. Daily 2.5mg suits men who get side effects on 5mg but still want daily dosing.
The safety rule is simple. Never take more than one dose in 24 hours. Never combine tadalafil with another PDE5 inhibitor, such as sildenafil or vardenafil.
Buying tadalafil through a GPhC-registered UK pharmacy, like Totiva, means you get proper dosing advice and a genuine, correctly labelled medicine. Counterfeit tadalafil sold outside regulated pharmacies is a real problem in the UK, and doses on fake packaging often don't match what's actually in the tablet.
Timeline: what to expect and when#
| Time after taking | What's happening |
|---|---|
| 0 to 30 minutes | Absorption starts. You won't feel an effect yet. |
| Around 2 hours (varies from 30 minutes to 6 hours) | Peak blood level (Tmax). Many men find this the most reliable window. |
| 30 minutes to 36 hours | An erection is possible with stimulation, at any point in this window. |
| After 36 hours | The drug is mostly cleared. The effect fades. |
| Daily dosing, day 5 onwards | Steady blood level reached. Timing stops mattering as much. |
Got questions? Speak to a pharmacist on WhatsApp now
Prefer to browse first? View treatments
What changes this timeline#
A very high-fat meal can slightly delay absorption of tadalafil, though it doesn't reduce how well it works overall. This is different from sildenafil, which is more affected by food.
Alcohol can make it harder to get an erection on its own, and heavy drinking on top of tadalafil can blunt the effect further. Poor cardiovascular health, including high blood pressure or high cholesterol, also reduces blood flow and can make any ED treatment work less well.
Some medicines change how tadalafil should be used. Non-selective alpha-blockers, such as doxazosin and terazosin, carry a higher risk of a sudden drop in blood pressure when combined with tadalafil. Tamsulosin, a more selective alpha-blocker often used for BPH, carries a lower but still real risk, and needs caution rather than avoidance.
Nitrate medicines for angina, including GTN spray and isosorbide, must never be combined with tadalafil. This also includes nicorandil and recreational nitrite drugs known as poppers (amyl nitrite). Mixing any of these with tadalafil can cause a dangerous, sudden fall in blood pressure.
If you have reduced kidney or liver function, you may need a lower starting dose. This should be worked out with your prescribing clinician, not adjusted on your own.
Missed or late dose#
On-demand tadalafil doesn't really have a "missed dose" scenario. You simply take it before you next plan to have sex, waiting at least 24 hours since your last dose.
For daily tadalafil, if you forget your usual time, take it as soon as you remember that day. If it's almost time for your next daily dose, skip the missed one and carry on as normal the next day. Never take two daily doses close together to make up for a missed one.
If you've taken more than your prescribed dose, or you're not sure how much you've taken, contact a pharmacist or call NHS 111 for advice.
If you're ready to look at ED treatment options properly assessed for your health, Totiva's blog has more guidance on comparing PDE5 inhibitors, and you can browse further reading at /blog.
Not sure which treatment is right for you?
Medical Information: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting, stopping, or changing any treatment.
