Cialis vs Viagra: The key differences

Reviewed by Dr Bhavini Shah

Although Viagra is the most well-known medication for erectile dysfunction, several alternative treatments are available including Cialis. Both treatments can help men achieve satisfying erections and beat erectile dysfunction. However they have differing characteristics which will suit different men in different ways. 

In this article we explore the ways that Viagra and Cialis are different, including dosages available and effectiveness.  

What is the difference between Cialis and Viagra?

Viagra and Cialis have different active ingredients although they’re both PDE-5 inhibitors. This means they relax the smooth muscles in the blood vessels supplying the penis. This relaxation increases blood flow to aid an erection. In Viagra the PDE-5 inhibitor is sildenafil, while in Cialis it is tadalafil.

However, both drugs require a sexual stimulus to take effect. Neither Viagra or Cialis will cause an erection on their own.

History of Viagra and Cialis

Viagra was launched in 1998 by Pfizer. It was approved by the European Medicines Agency and US Food and Drug Administration, as the first oral drug to treat erectile dysfunction.

Following the launch of Viagra, Eli Lilly joined forces with the ICOS Corporation to develop taladalafil. It was approved for sale in 2002 in Europe and 2023 in the US. The drug was given the brand name Cialis.

“Viagra (sildenafil) was initially developed and tested in the UK to treat angina and was meant to relax the blood vessels that supply the heart. While the results for treating angina were disappointing, many participants reported developing erections after taking Viagra. Further research showed that Viagra relaxed the blood vessels supplying the erectile tissues.” - Dr Bhavini Shah 

How to take Viagra and Cialis

You should take Viagra on an empty stomach. If you have a large meal shortly before taking a pill, it will slow down the rate at which Viagra takes effect. In contrast, you can take Cialis before or after eating. With both treatments you should limit your alcohol intake to enjoy the greatest effects.

Cialis is faster-acting than Viagra:

• You can take Cialis as little as 30 minutes before you plan to have sex
• Viagra must be taken at least one hour before sex 

You may not respond to erectile dysfunction treatment the first time you take it. Don’t be alarmed if nothing happens. You should try taking the tablet up to eight times. If you don’t see any results, speak to your doctor or message us through your Patient Record. You may need to switch to a different dose or form of treatment.

Is Cialis more powerful than Viagra?

Both medications can help men achieve and sustain an erection during sex. Neither one is more powerful than the other, for example one cannot make you harder than the other.

The best treatment for you may depend on how often you have sex. Cialis and Viagra are taken on demand before sex, whereas Cialis Daily is an option for men who have sex three or more times a week. For many men Cialis works faster than Viagra and the effects can last for longer.

Common side effects of Cialis and Viagra

As with any medication you may experience side effects when taking Cialis or Viagra. Side effects may be more common in people who take higher doses of ED medication.

Cialis side effects

Common Cialis side effects include:

• Headache
• Indigestion
• Stomach cramps
• Back pain
• Flushing
• Nasal congestion 

Viagra side effects

Common Viagra side effects include:

• Headaches
• Nausea
• Hot flushes
• Indigestion
• Blocked nose
• Dizziness 

If you’re worried about any side effects, speak to your doctor or message our clinicians through your Patient Record.

Cialis and Viagra considerations

It can be hard to know which ED treatment is right for you. There are lots of things to consider if you’re comparing treatments such as dose, safety and duration of effects.  

Dosage

The dosage of a medicine relates to how much active ingredient it contains. Higher doses tend to have stronger effects. However, the right dosage for you will depend on your own needs and whether you have any health conditions.

Cialis and Viagra are available in the following dosages:

Through our Online Doctor service our clinicians will review your answers to our online questionnaire. This will make sure you’re being prescribed the treatment that will most help you. 

Active ingredient

Some men may react better to one active ingredient than the other. Viagra contains the active ingredient sildenafil whereas Cialis contains tadalafil. Both sildenafil and tadalafil work via the same mechanism to help you achieve and keep an erection. However, tadalafil stays in the bloodstream for longer.

Because they work in the same way you should never take the two drugs together. Nor should you take more than one Viagra or Cialis pill at any one time. 

Duration of effects

The biggest difference between Viagra and Cialis is the amount of time their effects last:

• Viagra remains effective for 4 to 6 hours, which offers ample opportunity to have sex on multiple occasions if you wish
• Cialis typically allows you to achieve erections for up to 36 hours after taking a tablet

Although Cialis lasts for up to 36 hours, this does not mean you will have an erection throughout that time – it should only happen when you are sexually stimulated. Cialis has comfortably the longest effectiveness period of any erectile dysfunction drug on the market.

Safety

Side effects for either drug are rare but not unheard of. As Cialis and Viagra are both PDE-5 inhibitors, they have similar side effects. Although you may find that because Cialis is effective for longer, any side effects you experience may also last for longer. The most likely unwanted effects are: 

• light-headedness
• headaches
• flushing to the face

Nasal congestion, indigestion and visual changes are sometimes experienced as well.

If you experience chest pain or a prolonged erection for more than four hours, you must seek urgent medical help. Both Viagra and Cialis are prescription drugs so you must consult with a doctor before you can take them. 

Cost

Cost is another notable distinction between Viagra and Cialis. The longer effectiveness of Cialis is reflected in its price. While Cialis is slightly more expensive than Viagra, many men will consider the vastly greater duration period of Cialis to represent good value for money. Equally, plenty of men will prefer the cheaper price and renowned brand name offered by Viagra. But ultimately it depends entirely on the individual.

Conclusion

Though many people would like to know which treatment is better, there really is no straightforward answer to that question. As we’ve seen Viagra and Cialis have their similarities and differences.

The effectiveness of the treatment varies from one man to another, depending on the cause of the erectile dysfunction, its severity and the amount of sexual stimulation the person receives. Until you try for yourself, you cannot be sure of the exact results you will achieve.

Start a consultation today and our clinicians can recommend, and if appropriate prescribe Viagra or Cialis to you.  

References

www.pharmaceutical-journal.com/news-and-analysis/infographics/three-decades-of-viagra/20202847.article
www.nhs.uk/medicines/sildenafil-viagra/
www.medicines.org.uk/emc/product/7124/pil#gref
www.medicines.org.uk/emc/product/7430/pil#gref