ED Medication · PDE5 Inhibitor · FDA-approved · Daily option available
Cialis®
(Tadalafil)
The “weekend pill” — Cialis lasts up to 36 hours compared to Viagra’s 4–6, is not affected by food, and uniquely offers a daily low-dose option that allows spontaneous sex without planning around a dose. Often preferred by men who find the timing requirements of Viagra inconvenient.
Tadalafil is also FDA-approved for benign prostatic hyperplasia (BPH) at 5mg daily — meaning men with both ED and prostate symptoms may address both with one daily medication.
Two ways to use Cialis
As-needed vs. daily — understanding both options
Tadalafil is unique among PDE5 inhibitors in offering two meaningfully different treatment approaches. The right choice depends on how frequently you’re sexually active and your lifestyle preferences.
How it differs from Viagra
Why tadalafil lasts so much longer
Tadalafil and sildenafil are both PDE5 inhibitors working through the same mechanism — but tadalafil has a half-life of approximately 17.5 hours compared to sildenafil’s 4 hours. This is why tadalafil provides a 36-hour window while sildenafil provides 4–6 hours.
The longer half-life also means tadalafil is not affected by food — since it is absorbed more slowly and steadily regardless of gastric content. A high-fat meal that significantly delays sildenafil has minimal effect on tadalafil.
The trade-off is that side effects — particularly muscle aches and back pain which are more common with tadalafil than sildenafil — may also last longer when they occur. Most men who experience these find them mild and manageable.
Sildenafil is more selective for PDE5 than tadalafil. Tadalafil also inhibits PDE11, which is found in skeletal muscle. This is why muscle aches and back pain are reported more commonly with tadalafil than sildenafil — PDE11 inhibition in muscle tissue.
These aches typically occur 12–24 hours after dosing and resolve within 48 hours. Many men find them mild or don’t experience them at all. If they are a problem, sildenafil’s higher PDE5 selectivity may be a better fit.
FDA-approved 5mg daily tadalafil is indicated for both ED and BPH (enlarged prostate with urinary symptoms). Men who have both conditions can address both with a single daily medication — a meaningful practical advantage. Discuss with your urologist if BPH is a factor.
Side effects
What to know about tadalafil side effects
Headache — common; typically mild and resolves within a few hours
Back pain and muscle aches — more common than with sildenafil; usually mild, resolves in 48 hours
Facial flushing — less common than with sildenafil at standard doses
Nasal congestion — mild stuffiness, temporary
Indigestion — mild GI discomfort in some men
Blood pressure drop — as with all PDE5i; critical with nitrates
Common questions
Frequently asked questions
Should I choose as-needed or daily dosing?
If you’re sexually active 2 or more times per week, daily low-dose tadalafil is often more cost-effective and convenient than as-needed dosing. If sexual activity is less frequent, as-needed 10mg or 20mg may be more appropriate. Daily dosing also eliminates the planning aspect — which some men find psychologically beneficial for performance anxiety. Discuss with your provider which approach suits your lifestyle.
Does daily Cialis make erections happen all the time?
No. Like all PDE5 inhibitors, tadalafil requires sexual arousal to be present for an erection to occur — it doesn’t cause spontaneous erections. Daily low-dose simply maintains a background level of PDE5 inhibition so that when arousal does occur, the vascular response is better supported. Spontaneous erections from the medication alone are not expected.
Can I switch from Viagra to Cialis?
Yes — switching between PDE5 inhibitors is common and safe when directed by your physician. Men who find sildenafil’s food interaction inconvenient, want a longer window, or prefer not to time a dose before activity often find tadalafil better suited to their lifestyle. Generic tadalafil is also now widely available at low cost, comparable to generic sildenafil.
Is Cialis better than Viagra?
Neither is objectively better — they work through the same mechanism with similar efficacy. The differences are practical: Cialis lasts longer and has no food effect; Viagra is faster to reach peak effect and is slightly more PDE5-selective (fewer muscle aches). Men who value spontaneity and don’t want to plan around a dose tend to prefer Cialis. Men who want a faster, more time-limited effect tend to prefer Viagra. Both are equally effective for most men with vascular ED.
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Other options to consider
Get a prescription for tadalafil
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This page is for informational purposes only. Tadalafil requires a prescription. Never combine with nitrates. Cialis® is a registered trademark of Eli Lilly and Company. PhallusMD does not sell or prescribe medications.