Tadalafil vs Sildenafil: A Medically Accurate, UK-Guideline-Compliant Comparison
By Mr Suhail Jamil
Erectile dysfunction (ED) is commonly treated in the UK with sildenafil (e.g., Viagra) and tadalafil (e.g., Cialis). Both belong to a group of medicines called phosphodiesterase-5 (PDE5) inhibitors and are safe and effective for most men when prescribed appropriately.
About Tadalafil and Sildenafil
What they are
- Sildenafil and tadalafil are the active ingredients used in ED medicines in the UK.
- Sildenafil is found in brands such as Viagra.
- Tadalafil is found in Cialis and generic tadalafil.
How they work
Sexual arousal triggers the release of nitric oxide, which increases cyclic guanosine monophosphate (cGMP), relaxing blood vessels in the penis and allowing increased blood flow.
- PDE5 breaks down cGMP.
- PDE5 inhibitors (sildenafil and tadalafil) slow this breakdown, helping maintain sufficient blood flow for an erection when sexually stimulated.
- Neither increases libido.
How to take them
- Both medicines require sexual stimulation to work.
- Never take sildenafil and tadalafil together.
- Both are contraindicated with nitrates (used for angina) and certain other medicines due to the risk of dangerous drops in blood pressure.
Side effects (shared)
Common side effects include:
- headache
- flushing
- nasal congestion
- indigestion
- dizziness
Less common differences:
- Sildenafil may be more associated with temporary visual changes.
- Tadalafil may be more associated with muscle or back pain.
Both are generally well tolerated.
Differences Between Sildenafil and Tadalafil
Dosage (UK-accurate information)
Sildenafil (Viagra)
- Available as 25 mg, 50 mg, and 100 mg tablets.
- The usual starting dose is 50 mg, adjusted depending on effectiveness and tolerability.
Tadalafil (Cialis)
- Available as 2.5 mg, 5 mg, 10 mg, and 20 mg tablets.
There are two types of tadalafil use:
- On-demand: usually 10 mg before sexual activity (may increase to 20 mg if needed).
- Daily dosing: 2.5 mg or 5 mg once daily for men who prefer regular spontaneity.
You cannot take “50 mg or 100 mg tadalafil before sex.” Those doses do not exist and are not UK-licensed.
How food affects them
- Sildenafil: high-fat meals may delay absorption, so it is usually taken on an emptier stomach.
- Tadalafil: food does not significantly affect its absorption.
Onset of action
- Sildenafil: usually works in 30–60 minutes, sometimes longer after a large meal.
- Tadalafil: may work in as little as 16 minutes, but full effect may take up to 2 hours.
Duration of action
- Sildenafil: lasts for about 4–6 hours.
- Tadalafil: can last up to 36 hours, which is why it’s sometimes called the “weekend pill.”
This does not mean you have an erection for 36 hours—only that the drug remains active in your system during that window and may help you achieve an erection when aroused.
Cost
- Prices vary between pharmacies.
- Generic versions of both tadalafil and sildenafil are typically inexpensive in the UK.
- Tadalafil may be slightly more expensive due to its longer duration of action, but this depends on the pharmacy and format (daily vs on-demand).
Tadalafil Tablets for ED
Sildenafil Tablets (25mg, 50mg,100mg)
Order Monday to Friday before 14:00pm to guarantee next day delivery
How to Choose the Right ED Medication
The best choice depends on:
- how often you have sex (occasional vs frequent)
- how quickly you want the medication to work
- how long you want it to last
- your underlying health conditions
- side effect profile
- interactions with other medicines
General reasoning:
- Sildenafil may be suitable for occasional use when you can plan ahead.
- Tadalafil may be better if you prefer more spontaneity or want a longer window of effectiveness.
Discuss your symptoms, lifestyle, and medical history with a GP or pharmacist to choose the safest and most effective option.
Bottom Line
Both tadalafil and sildenafil are effective, safe, and widely prescribed ED treatments in the UK.
The right choice depends on your needs, health, and personal preference.
Always:
- use a UK-registered pharmacy
- follow the prescribed dose
- avoid combining PDE5 inhibitors
- avoid them entirely if you take nitrate medication
Sildenafil Tablets (25mg, 50mg,100mg)
Tadalafil Tablets for ED
Order Monday to Friday before 14:00pm to guarantee next day delivery
