Cialis vs Viagra: Which is better?

Dr Kathryn Basford

Medically reviewed by

Dr Kathryn Basford

Last reviewed: 21 Mar 2022

If you’re trying to find the right treatment for erectile dysfunction, you might be wondering what the difference is between Cialis and Viagra.

The active ingredients of Cialis (tadalafil) and Viagra (sildenafil) increase blood flow to your penis so you can get and maintain an erection. While both are effective medicines, there are some differences in how they work. You may want to use either Viagra or Cialis depending on your preference.

Contents
Bottles of Cialis and Viagra tablets
 

from £29.00

from £14.00

from £19.50

No results found.

No results found.
Please check your spelling or try another treatment name.

What’s the difference between Viagra and Cialis?

The main differences between Viagra and Cialis are:

  • how long they stay in your body
  • how quickly they take to work
  • how they’re affected by food

The effect of Cialis can last for up to 36 hours (a day and a half), whereas Viagra only works for up to 4 hours. If you are sexually excited within this time, you can get an erection. You may want to use Cialis if you are expecting to have sex but want to have more flexibility of when you have sex that day, or if you’re expecting to have sex more than once in 24 hours.

Cialis can also be taken as a low daily dose which may be a good option if you have sex more than twice throughout the week.

Both Viagra and Cialis will start to work within 30 minutes of taking a tablet. There’s a chance that Cialis will work as soon as 15 minutes after taking it.

Food affects Viagra and Cialis by slowing down how quickly the medicine gets into your bloodstream. By eating a fatty or heavy meal beforehand, it’ll take longer to get an erection. You can avoid this effect if you take Cialis in a small daily dose (as a 2.5mg or 5mg tablet), rather than just before sex.

Side effects

As Cialis and Viagra are from the same group of medicines, they can cause similar side effects.

Side effects of Cialis

The common side effects of Cialis are:

  • headache
  • muscle aches
  • flushing in your face
  • indigestion
  • muscle aches

Some less common side effects of Cialis include:

  • vomiting
  • dizziness
  • blurred vision
  • palpitations (a pounding or fast heartbeat)

Side effects of Viagra

Some common side effects of Viagra include:

  • nausea
  • headache
  • stuffy nose
  • dizziness
  • blurred vision

Uncommon side effects of Viagra are:

  • dry mouth
  • a rapid heartbeat
  • being more sensitive to light

Dosage

The normal starting dose for Viagra is a 50mg tablet taken an hour before you expect sex. Viagra is available in 25mg, 50mg and 100mg tablets.

The starting dose for Cialis is a 10mg or 20mg tablet taken 30 minutes before sex. Cialis also comes in 2.5mg or 5mg tablets that you can take daily.

Your doctor will decide which dose is right for you. They can also adjust the dose if you need a stronger or weaker effect.

Interactions with other medicines

Cialis and Viagra can interact with other medicines. Both Cialis and Viagra are part of a group of medicines called phosphodiesterase type 5 (PDE 5) inhibitors. They help you to get an erection by increasing the blood flow to your penis.

You should not take more than 1 type of erectile dysfunction medicine on the same day. So if you use 1 Viagra tablet, you need to wait 24 hours if you want to take a Cialis tablet.

Some medicines that interact with both Viagra and Cialis include:

  • treatment for high blood pressure called alpha-blockers, such as doxazosin
  • specific antibiotics, such as erythromycin or clarithromycin
  • antifungal medication, such as itraconazole or fluconazole
  • epilepsy treatment, such as phenytoin, carbamazepine or phenobarbital
  • ritonavir for HIV
  • medicines that contain nitrates, such as glyceryl trinitrate (GTN) for angina
  • nitric oxide donors, such as amyl nitrite, also called ‘poppers’
  • riociguat

Speak to a doctor if you are taking any of these medicines and want to try Cialis or Viagra.

Summary

You can use either Viagra or Cialis to treat erectile dysfunction as both are effective. Cialis works for longer after you’ve taken it. You may choose to use Cialis Daily if you think you’ll have sex more than twice in 1 week or usually eat meals that have a high fat content.

dr-kathryn-basford.png
Medically reviewed by:
Dr Kathryn Basford

Dr Kathryn Basford is a qualified GP who works as a GP in London, as well as with ZAVA. She graduated from the University of Manchester and completed her GP training through Whipps Cross Hospital in London.

Meet our doctors

Article created: 28 Oct 2021

Last reviewed: 21 Mar 2022

Don’t miss the latest advice from our doctors, and more. Sign up for our regular newsletter.
Sign up today

Asda Online Doctor by ZAVA offers a convenient and discreet service to help men improve their erectile dysfunction. There are a number of treatments you can consider. Continue to our erectile dysfunction service page to learn about the treatment options available.



(Reviews are for ZAVA UK)

ZAVA logo
gmc logo GPC logo

Authorised and regulated by