How Long Does Cialis Last?

Quick Answer

A single as-needed dose of Cialis (tadalafil) lasts up to 24–36 hours, meaning it can help with erections across that entire window when you're sexually aroused. It typically starts working in 30–60 minutes. The low-dose daily form (2.5 mg or 5 mg) keeps a steady level in your body so you're covered anytime, without timing doses around activity.

How Long Cialis Lasts vs. Other ED Drugs

Medication	Onset	Duration
Cialis (tadalafil)	30–60 minutes	Up to 36 hours
Viagra (sildenafil)	30–60 minutes	4–6 hours
Levitra (vardenafil)	30–60 minutes	4–8 hours
Stendra (avanafil)	15–30 minutes	6 hours

Why Cialis Lasts So Long

Tadalafil has a half-life of about 17.5 hours—much longer than sildenafil's 4 hours. It takes several half-lives to fully clear, which is why effects can persist up to a day and a half. Importantly, Cialis does not cause a continuous erection; it simply allows you to get one in response to arousal during that window. The drug is fully out of most people's systems within a few days.

Factors That Affect How Long It Lasts

• Dose — higher as-needed doses (10–20 mg) tend to last toward the upper end.
• Daily vs. as-needed — daily dosing provides continuous readiness rather than a single window.
• Metabolism and age — older adults and slower metabolizers clear it more slowly.
• Kidney and liver function — impairment prolongs the effect and may require dose limits.
• Food and alcohol — Cialis is not affected by food, but heavy alcohol can worsen side effects.

Getting the Best Results

• Take as-needed Cialis at least 30–60 minutes before sexual activity.
• Remember it works only with sexual arousal—it is not an automatic erection.
• Don't take more than one dose in 24 hours (as-needed) or combine with the daily version.
• Never combine Cialis with nitrate heart medications; the drop in blood pressure can be dangerous.
• Talk to your doctor about the daily low dose if you want spontaneity without timing.

When to See a Doctor

Seek emergency care for an erection lasting more than 4 hours (priapism), which can permanently damage tissue, or for sudden vision or hearing loss. Stop and get help for chest pain during sex, which may signal a heart problem. Tell your doctor about all medications—especially nitrates and alpha-blockers—and any heart conditions before starting Cialis. Also consult a doctor if erectile dysfunction persists, since it can be an early warning sign of cardiovascular disease.