Tadalafil 5 mg vs 20 mg

Tadalafil 5 mg is the low dose taken once a day, for erectile dysfunction, an enlarged prostate (BPH) or both, while 10 mg and 20 mg are taken as needed before sex. The Cialis label starts as-needed use at 10 mg and daily use at 2.5 mg, so 20 mg is the top of the as-needed range and 5 mg the top of the daily one.

Both regimens worked in trials. The choice comes down to how often you have sex, whether you also have urinary symptoms, how you handle side effects and what you want to spend. Everything below is from the FDA-approved Cialis label unless a provider is named. For when each dose starts working and how long it lasts, see how long Cialis lasts.

Tadalafil dosage at a glance

Scroll sideways to see the full table

The Cialis label, revised in March 2026, lists 5 mg, 10 mg and 20 mg tablets and says not to split them; generic tadalafil also comes as a 2.5 mg tablet, according to the National Library of Medicine’s RxNorm database. Take tadalafil with or without food.

Tadalafil 5 mg daily: who it suits

Daily tadalafil is taken at about the same time each day, without timing it to sex. The label starts at 2.5 mg and allows 5 mg, based on how well it works and how well you tolerate it. It was tested in three trials of 12 or 24 weeks with 853 men.

On the 30-point erectile function score, daily 5 mg raised scores by 7.0 points in a 24-week US trial and 9.7 points in a 12-week trial outside the US, against 1.2 and 0.9 on placebo; 2.5 mg raised them by 6.1. In the 6-month study, the effect didn’t fade.

The same 5 mg dose is approved for BPH. In two 12-week trials, the prostate symptom score (0 to 35, higher is worse) fell by 4.8 and 5.6 points on tadalafil, against 2.2 and 3.6 on placebo. The label doesn’t recommend tadalafil with alpha-blockers such as tamsulosin for BPH, because the combination wasn’t adequately studied and can lower blood pressure.

Daily 5 mg suits men who have sex often, would rather not plan around a pill, or also have urinary symptoms. Compare clinics in our daily tadalafil rankings.

Tadalafil 20 mg as needed: who it suits

As-needed tadalafil is taken before sex, no more than once a day. The label starts most men at 10 mg and lets the dose rise to 20 mg or fall to 5 mg. It was tested in 22 trials of up to 24 weeks with more than 4,000 men.

In the two main US trials of 20 mg, erectile function scores rose by 6.9 and 9.3 points, against almost no change on placebo. Men’s erections lasted long enough for intercourse in 50% and 64% of attempts by the end of the trials, against 25% and 23% on placebo. The label says as-needed tadalafil improved erectile function for up to 36 hours after a dose.

The 20 mg dose suits men who have sex now and then, and for whom 10 mg wasn’t enough. If you have sex a few times a month, as-needed doses usually cost less than 30 daily tablets.

Tadalafil 10 mg: the usual starting point

Most men start as-needed tadalafil at 10 mg. Some never need more, and 10 mg is also the highest as-needed dose the label allows for men with moderate kidney disease, mild or moderate liver disease, or strong CYP3A4 inhibitors such as ketoconazole or ritonavir, with longer gaps between doses in some of those cases.

Side effects by dose

From the label’s 12-week placebo-controlled trials:

Scroll sideways to see the full table

Most side effects were more common at the higher as-needed doses, and the daily doses caused fewer than 10 mg or 20 mg. Back pain and muscle aches generally started 12 to 24 hours after a dose and eased within 48 hours. In the as-needed trials, 3.1% of men on 10 mg or 20 mg stopped because of side effects, against 1.4% on placebo; in the daily trials, 4.1% against 2.8%.

The serious warnings are the same at every dose. Never take tadalafil with nitrates in any form or with riociguat, because blood pressure can drop dangerously. Five or more units of alcohol with it can also lower blood pressure. Get emergency care for an erection lasting more than 4 hours, and stop and seek care for sudden loss of vision or hearing.

Who should start lower

The label lowers the dose for some men:

• Kidneys. With creatinine clearance of 30 to 50 mL/min, as-needed use starts at 5 mg, up to 10 mg once every 48 hours. Below 30 mL/min or on dialysis, the as-needed maximum is 5 mg once every 72 hours, and daily use isn’t recommended.
• Liver. With mild or moderate liver disease, as-needed doses shouldn’t exceed 10 mg a day, and daily use needs caution. With severe liver disease, tadalafil isn’t recommended.
• Other medicines. With strong CYP3A4 inhibitors, the as-needed maximum is 10 mg once every 72 hours and the daily maximum is 2.5 mg.
• Alpha-blockers. For ED, you should be stable on the alpha-blocker first and start tadalafil at the lowest dose.

What each dose costs online

Prices on each provider’s own site, as of October 2026:

MyDrHank doesn’t say clearly whether its tablets are FDA-approved generics or compounded, and RxSpan MD and Bodybuilding.com Health+ don’t state it either. At Strut, a 20 mg dose costs four times a 5 mg dose, but per tablet the gap can be small elsewhere: TRT Nation’s 20 mg tablets work out to about $3.33 each. At that price, four 20 mg doses a month work out to about $13 of a $99.99 pack, against $35 to $40 for a month of daily tablets at MyDrHank or Hims. If you have sex most days, the daily plan narrows that gap. For the terms behind each price, see what Cialis costs and where generic Cialis is cheapest.

The bottom line

Tadalafil 5 mg is the daily dose, for ED, BPH or both; 10 mg and 20 mg are the as-needed doses, taken before sex no more than once a day. Both worked well in trials, and side effects were lowest on the daily doses and highest at 20 mg. Daily tadalafil suits frequent sex or urinary symptoms; as-needed 10 mg or 20 mg is usually cheaper for occasional use. Don’t split tablets, and check kidney, liver and medicine limits with your clinician. More on tadalafil, in our ED provider rankings and on the ED hub.