Cialis vs Viagra: which is best?

Dr. Babak Ashrafi

Medically reviewed by

Dr Babak Ashrafi

Last reviewed: 23 May 2022

Cialis and Viagra are both medicines used to treat erectile dysfunction. Erectile dysfunction is where a man cannot get or keep an erection long enough to have sex. Erectile dysfunction is also known as impotence.

Contents
 

There are many different causes of erectile dysfunction, including:

  • psychological reasons, such as stress or performance anxiety
  • lifestyle choices, such as smoking or drinking alcohol
  • health conditions, such as heart disease or diabetes
  • physical reasons, such as blood vessel or nerve damage

There are now a number of different erectile dysfunction treatments available. These treatments have been used successfully by many men to manage erectile dysfunction. Two of the most well known treatments for erectile dysfunction are Cialis and Viagra. Let’s look at some of the differences between Viagra and Cialis to understand a bit more about which one might be best for you.

To request Cialis, Viagra, or another erectile dysfunction treatment, complete our short online medical questionnaire. Our doctors can prescribe treatment within a few hours once they’ve checked this is suitable for you. If you have any questions about erectile dysfunction or which treatment may be right for you, you can privately message our doctors through your account, free of charge.

What is the difference between Cialis and Viagra?

Cialis and Viagra are both phosphodiesterase type 5 (PDE5) inhibitors, but the difference is that they contain different active ingredients. Both Viagra and Cialis work by relaxing the smooth muscle in the blood vessels of the penis, allowing an increase in blood flow. This helps you to create and maintain an erection.

Viagra and Cialis are similar in how effective they are in treating erectile dysfunction. But one of the main differences between Cialis and Viagra is how long the effects last. The effects of Cialis can last for up to 36 hours. This is longer than the effects of Viagra, which usually last for 4 to 6 hours.

Side effects

Both Cialis and Viagra can cause side effects, although these are usually mild and not everyone gets them. You may experience slightly different side effects with Viagra and Cialis. In general, side effects are similar because they are both PDE5 inhibitors and work in similar ways.

The most common side effects of Cialis are:

  • headache
  • back pain
  • muscle aches
  • arm or leg pain
  • facial flushing
  • nasal congestion
  • indigestion

The most common side effects of Viagra are:

  • headache
  • nausea
  • facial flushing
  • hot flushes
  • indigestion
  • colour tinge, blurred vision, or visual disturbance
  • nasal congestion
  • dizziness

With both Cialis and Viagra, drug interactions can occur if they are taken at the same time as some other medicines. These can occur with some commonly prescribed medicines such as nitrates like amyl nitrite (used to treat angina or chest pain) and alpha blockers (for high blood pressure). You should let your doctor know about any other medicines you are taking, or planning to take, before taking Cialis or Viagra. Your doctor can advise if Cialis or Viagra will be suitable for you.

With both Cialis and Viagra, if you have certain medical conditions the medicines may not be suitable for you. This includes some heart conditions, low blood pressure and if you have recently had a heart attack or stroke. You should speak to your doctor for advice.

Cialis is a prescription only medication. This means you can only buy Cialis with a prescription. Cialis is sometimes also taken to treat an enlarged prostate.

Viagra is available as an over the counter medication at a 50mg dose (Viagra Connect). You will need a prescription to buy Viagra at other doses, such as 25mg or 100mg.

Active ingredients

Viagra and Cialis contain different active ingredients.

Cialis contains the active ingredient tadalafil. Cialis is available from ZAVA in tablets containing 10mg or 20mg of tadalafil.

Viagra contains the active ingredient sildenafil. Viagra is available from ZAVA in tablets containing 25mg, 50mg or 100mg of sildenafil.

How quickly they start to work

Cialis and Viagra differ slightly in how quickly they start to work:

  • Cialis usually takes around 30 to 60 minutes to work
  • Viagra usually takes around 1 hour to work

With both Cialis and Viagra, you will need to be sexually stimulated for the medicines to have an effect. Cialis and Viagra will not lead to an erection without sexual stimulation.

How long they last

The effects of Cialis and Viagra last for different lengths of time:

  • Cialis can last for up to 36 hours
  • Viagra usually last for 4 to 6 hours

The difference in how long Cialis and Viagra last may affect which is most suitable for you.

Cialis is also available at a lower dose (called Cialis daily). This may be suitable if you want to be able to get an erection at any time and are happy to take a low dose, 2.5mg or 5mg, tablet every day.

How to take Viagra or Cialis

With Cialis, you should take a tablet at least 30 minutes before sexual activity.

With Viagra, you should take a tablet at least 1 hour before sexual activity.

With either Cialis or Viagra, swallow the tablet whole with a glass of water.

You can take Cialis or Viagra with food. With Viagra, you may find it takes longer to work if you take it at the same time as a heavy meal.

Avoid drinking more than 2 or 3 units of alcohol whilst taking Cialis or Viagra. Drinking a high level of alcohol can make it harder to get and maintain an erection.

Avoid drinking grapefruit juice whilst taking Cialis or Viagra. Grapefruit juice can increase the side effects of Cialis and Viagra.

Cialis vs Viagra price

The price of Cialis vs Viagra depends on the dose and the number of pills you order. Viagra is usually slightly cheaper, for example 4 tablets of Viagra 50mg cost £25 and 4 tablets of Cialis 10mg cost £39.

The usual starting dose of Viagra is 50mg.

The usual starting dose of Cialis is 10mg.

You can view the available pack sizes and prices of Cialis and Viagra from ZAVA. Complete our online questionnaire and a ZAVA doctor will review what medication might be suitable for you.

If you are not sure what medication might be best for you, you can order a trial pack of erectile dysfunction medicine from ZAVA. The trial pack contains 4 tablets of Cialis, 4 tablets of Viagra, and 4 tablets of Levitra (another erectile dysfunction medicine).

babak-updated-roundpng.png
Medically reviewed by:
Dr Babak Ashrafi Clinical Lead for Service Expansion
Accreditations: BSc, MBBS, MRCGP (2008)

Babak studied medicine at King’s College London and graduated in 2003, having also gained a bachelor’s degree in Physiology during his time there. He completed his general practice (GP) training in East London, where he worked for a number of years as a partner at a large inner-city GP practice. He completed the Royal College of GPs membership exam in 2007.

Meet our doctors

Last reviewed: 23 May 2022

Get £5 off your next order when you sign up to our newsletter.
Sign up today





Authorised and regulated by