Tadalafil (the ingredient in Cialis) and sildenafil (the ingredient in Viagra) are the two most widely used medicines for erectile dysfunction (ED). Both are PDE5 inhibitors and work in a similar way, but they differ a lot in how long they last and how flexible they are.
Side-by-side comparison
| Tadalafil | Sildenafil | |
|---|---|---|
| Same medicine as | Cialis | Viagra |
| Starts working | About 30 minutes to 2 hours | About 30 to 60 minutes |
| How long it works | Up to 36 hours | About 4 to 6 hours |
| Effect of a heavy meal | Little effect | Can delay onset |
| Daily low-dose option | Yes, 2.5 mg or 5 mg once a day | No |
| Usual as-needed doses | 10 mg start, 20 mg maximum | 50 mg start, 100 mg maximum |
| Typical side effects | Headache, indigestion, back pain, muscle aches | Headache, flushing, stuffy nose, blue-tinted vision |
Which lasts longer?
Tadalafil, by a wide margin. Its effect can last up to 36 hours, which is why it is sometimes called the “weekend pill”. Sildenafil’s effect usually lasts 4 to 6 hours. Neither medicine causes a continuous erection: both only help when there is sexual stimulation.
Which works faster?
They are similar. Sildenafil usually starts working within 30 to 60 minutes on an empty stomach. Tadalafil can start in about 30 minutes but may take up to 2 hours. A heavy, fatty meal can slow sildenafil down; it has little effect on tadalafil.
Which is better for you?
- Tadalafil may suit men who want more spontaneity, who prefer not to plan around meals, or who would like a daily low dose. 5 mg daily is also used for symptoms of an enlarged prostate (BPH).
- Sildenafil may suit men who only need it occasionally and prefer a shorter effect, or who get back pain or muscle aches with tadalafil.
Both are effective for most men. Your doctor will consider your health, other medicines and preferences.
Safety for both
- Never take either with nitrates (such as nitroglycerin), “poppers” or riociguat.
- Do not take both medicines together.
- Seek urgent help for an erection lasting more than 4 hours, chest pain, or sudden loss of vision or hearing.
- Tell your doctor about heart, liver or kidney problems and all medicines you take.
Compare brands and prices
Both ingredients are sold under many generic brand names, such as Vidalista and Tadalista for tadalafil, or Cenforce, Fildena and Kamagra for sildenafil. Compare them by price per tablet:
Frequently asked questions
Is tadalafil stronger than sildenafil?
Not stronger, just longer-lasting. At their usual doses both are effective; tadalafil gives a much longer window.
Can I switch from sildenafil to tadalafil?
Yes, but only with your doctor’s advice, and never take them on the same day.
Do I need a prescription?
Yes. Both are prescription medicines. ERXCart asks you to upload a valid prescription at checkout and checks it before dispatch.
This article is general information and does not replace advice from your doctor or pharmacist.