How long does Viagra last? Sildenafil, tadalafil and what affects it

"How long does Viagra last?" has a precise answer that depends on which medicine you mean. Sildenafil-based products (Viagra, Kamagra, Cenforce) work for around four hours; tadalafil lasts far longer. Here's exactly what "lasts" means and what changes it.

The short answer

Sildenafil works for about four hours. That's the window during which it can support an erection when you're aroused — it does not mean a four-hour erection. Onset is typically 30–60 minutes (15–30 for the oral jelly). Tadalafil (Cialis, Vidalista) is different: a single dose lasts up to 36 hours, which is why it's called the weekend pill.

What affects how long it lasts

Food (a heavy meal delays onset and can blunt the effect), alcohol (works against erections and shortens perceived benefit), dose, age and metabolism all play a part. Grapefruit juice raises sildenafil levels unpredictably and should be avoided — see mixing sildenafil with drinks. None of these extend the medicine beyond its natural window; they mostly shorten or delay it.

Sildenafil vs tadalafil for duration

If you want a defined evening, sildenafil's four hours is plenty and it's cheapest per dose. If you value spontaneity, tadalafil's 36-hour window — or low-dose daily tadalafil — removes the clock entirely. The head-to-head is in tadalafil vs sildenafil.

How often can you take it?

One dose per 24 hours for both — the duration windows don't stack, and taking more doesn't extend or strengthen the effect, only the side effects. If an erection lasts more than four hours (priapism), seek emergency care.

Making the most of the window

Take it on a lighter stomach, minimise alcohol, and remember it amplifies arousal rather than creating it — so the medicine works best alongside genuine desire and a relaxed setting. Full pharmacology in the complete Kamagra guide.

Key points to remember

• The short answer: Sildenafil works for about four hours. That's the window during which it can support an erection when you're aroused — it does not mean a four-hour erection. Onset is typically 30–60 minutes (15–30 for the oral jelly).
• What affects how long it lasts: Food (a heavy meal delays onset and can blunt the effect), alcohol (works against erections and shortens perceived benefit), dose, age and metabolism all play a part. Grapefruit juice raises sildenafil levels unpredictably and should be avoided — see mixing sildenafil with drinks.
• Sildenafil vs tadalafil for duration: If you want a defined evening, sildenafil's four hours is plenty and it's cheapest per dose. If you value spontaneity, tadalafil's 36-hour window — or low-dose daily tadalafil — removes the clock entirely.
• How often can you take it?: One dose per 24 hours for both — the duration windows don't stack, and taking more doesn't extend or strengthen the effect, only the side effects. If an erection lasts more than four hours (priapism), seek emergency care.
• Making the most of the window: Take it on a lighter stomach, minimise alcohol, and remember it amplifies arousal rather than creating it — so the medicine works best alongside genuine desire and a relaxed setting. Full pharmacology in the complete Kamagra guide.

Common questions

How long does Viagra (sildenafil) last?

About four hours — the window in which it can support an erection with arousal. Onset is 30–60 minutes, faster (15–30) for the oral jelly.

Which ED pill lasts the longest?

Tadalafil (Cialis/Vidalista) — up to 36 hours from a single dose, versus around four hours for sildenafil. It's why tadalafil is nicknamed the 'weekend pill'.

Does Viagra keep you hard for hours?

No — it doesn't cause a continuous erection. It provides a roughly four-hour window in which arousal can produce an erection. An erection lasting over four hours needs emergency care.

Can I make Viagra last longer?

No trick extends it beyond its natural window; food and alcohol mostly shorten it. For a longer window, tadalafil (up to 36 hours) is the option to discuss with a doctor.

References & further reading

• NHS: Sildenafil (Viagra) — uses, dosage, side effects — official UK guidance on the active ingredient.
• Goldstein I, et al. NEJM 1998 — the pivotal sildenafil trial — lead-authored by Dr. Irwin Goldstein (San Diego Sexual Medicine).
• Phosphodiesterase 5 Inhibitors — StatPearls, NCBI Bookshelf — clinical pharmacology reference.

This article is general information, not medical advice. Always consult a healthcare professional before starting any medication.