Sildenafil vs tadalafil: what is the difference?
Author: Vitalis Natura Editorial · Published: 2026-07-14 · Last updated: 2026-07-14
This content is informational only and does not replace medical advice. Consult a qualified health professional for personal guidance.
Sildenafil vs tadalafil: what is the difference?
Short answer: the active ingredient is different, but both belong to the PDE5 inhibitor group. The differences are duration, food effects, authorised doses and individual health risks.
> This text is informational. A doctor or pharmacist should determine the choice and dose. Do not combine two PDE5 inhibitors.
Quick comparison
| Feature | Sildenafil | Tadalafil |
|---|---|---|
| Authorised ED tablet strengths | 25, 50, 100 mg | 2.5, 5, 10, 20 mg |
| Typical onset | about 30–60 minutes | may be taken at least 30 minutes beforehand |
| Duration | a shorter window, usually several hours | effect may be present for up to 36 hours |
| Food | a high-fat meal may delay onset | can be taken without regard to food |
| Sexual stimulation | required | required |
These figures apply to authorised formulations and do not prove that every package or unusual strength has the same profile.
How do they work?
Both inhibit PDE5 and support the normal blood-vessel response to sexual stimulation. Neither automatically increases desire nor creates an erection without stimulation.
Who should not use them without medical assessment?
Particular caution is needed for people taking nitrates for chest pain or riociguat, those with unstable cardiovascular disease, very low blood pressure, alpha-blockers or strong CYP3A4 inhibitors, or serious liver/kidney disease.
Why shouldn't they be combined?
Combining two PDE5 inhibitors can excessively lower blood pressure and increase the risk of side effects.
When is urgent help needed?
Seek urgent medical help for chest pain, an erection lasting more than four hours, sudden loss of vision/hearing, difficulty breathing or a severe allergic reaction, or fainting.
Vitalis Natura products
- Sildenafil: Kamagra Gel 100mg
Tadalafil safety details: Tadalafil safety and interactions. For sildenafil: Sildenafil safety.
Sources
European Medicines Agency — Cialis/tadalafil and Viagra/sildenafil product information; Eli Lilly and Pfizer/Viatris prescribing information.
*Last editorial review: 14 July 2026.*
