Tadalafil vs Sildenafil: Which Is Better for Erectile Dysfunction?
Duration, food effects, daily dosing, side effects and which suits your lifestyle.
Part of the Access Doctor Erectile Dysfunction guide.
Key fact: Both tadalafil and sildenafil have similar clinical effectiveness — approximately 81–82% success rates. The choice between them comes down to lifestyle preference, not efficacy. If you want spontaneity, choose tadalafil. If you prefer a defined window, choose sildenafil.
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Start Consultation →How Both Medications Work
Both sildenafil and tadalafil are PDE5 inhibitors. They block the phosphodiesterase type 5 enzyme in penile smooth muscle, preventing the breakdown of cyclic GMP (cGMP). The resulting accumulation of cGMP allows blood vessels in the penis to relax more easily when sexually stimulated, enabling increased blood flow and facilitating an erection. Sexual stimulation is required with both medications.
Key Differences: Tadalafil vs Sildenafil
| Feature | Sildenafil (Viagra) | Tadalafil (Cialis) |
|---|---|---|
| Duration of action | 4–6 hours | Up to 36 hours |
| Onset | 30–60 minutes | ~30 minutes |
| Affected by food? | Yes — avoid large/fatty meals | No |
| Daily option? | No | Yes (5mg daily) |
| Clinical effectiveness | ~82% of users | ~81% of users |
| Generic available? | Yes | Yes |
| Nickname | The blue pill | The weekend pill |
When Sildenafil Is the Better Choice
- You prefer a shorter-acting medication with a defined window of effectiveness
- Cost is a consideration — sildenafil generics are widely available at lower prices
- You prefer to take medication only immediately before planned sexual activity
- You are already using sildenafil and it is working well
When Tadalafil Is the Better Choice
- You want more spontaneity — not planning sex around medication timing
- You have sex frequently (more than twice a week) — daily 5mg tadalafil may be more convenient and cost-effective
- You prefer to take medication with food without worrying about absorption effects
- Your partner prefers the flexibility that a 36-hour window provides
Do not combine: Do not take sildenafil and tadalafil together or on the same day. Both are PDE5 inhibitors — combining them provides no additional benefit and significantly increases the risk of side effects including dangerously low blood pressure.
Side Effects — Similarities and Differences
Both share similar common side effects: headache, flushing, nasal congestion, and indigestion. Notable differences:
| Medication | Notable differences |
|---|---|
| Sildenafil | More commonly associated with temporary visual disturbances (blue tinge, altered colour discrimination) |
| Tadalafil | More commonly associated with back pain and muscle aches, related to its longer systemic presence |
For a full comparison of all four MHRA-approved ED medications, see our guide to Viagra vs Cialis vs Levitra vs Spedra.
Frequently Asked Questions
What is the main difference between tadalafil and sildenafil?
The key difference is duration: sildenafil (Viagra) lasts 4–6 hours. Tadalafil (Cialis) lasts up to 36 hours, offering significantly more spontaneity. Tadalafil is also not affected by food.
Which is more effective — tadalafil or sildenafil?
Clinical trials show similar efficacy: approximately 81% for tadalafil and 82% for sildenafil. There is no clinically significant difference. The choice is generally based on lifestyle preference.
Can I take tadalafil every day?
Yes. Tadalafil 5mg daily is available for continuous ED management, removing the need to plan around medication timing.
Does food affect tadalafil or sildenafil?
Food significantly affects sildenafil — a large, high-fat meal reduces absorption. Tadalafil is not meaningfully affected by food.
Can you take tadalafil and sildenafil on the same day?
No. Taking both risks severe side effects including hypotension, dizziness and priapism. Use one or the other.
Which ED medication is better for spontaneous sex?
Tadalafil, due to its 36-hour duration. Sildenafil requires more planning with its 1-hour onset and 4–6-hour window.
References
- National Institute for Health and Care Excellence (NICE). Erectile dysfunction: Clinical Knowledge Summary. Updated 2023. cks.nice.org.uk/topics/erectile-dysfunction
- NHS. Erectile dysfunction (impotence). nhs.uk/conditions/erection-problems-erectile-dysfunction
- Carson CC et al. Tadalafil, an oral phosphodiesterase type 5 inhibitor, for the treatment of erectile dysfunction. BJU Int. 2004. PubMed: 15142153
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. ED treatments are prescription-only medicines requiring clinical assessment. In a medical emergency, call 999.