Viagra vs Sildenafil

What is the difference between these two erectile dysfunction treatments?

Updated: Thursday 15 April 2021

comparing viagra and sildenafil

Viagra is possibly the most well-known erectile dysfunction medication in the world, if not the most popular. Viagra’s patent expired in 2013 in the UK, giving pharmaceutical companies the green light to manufacture and market the generic medication using the same active ingredient as Viagra, sildenafil citrate.

Viagra and Sildenafil are just that, the same medication under different names and sold at significantly varying prices. They are medically equivalent and thus have the same dosage, strength, active ingredient, quality and performance.

Without the branding and the advertising, the generic version is sold at a cheaper price than the brand-name counterparts.

  Viagra Sildenafil
Active Ingredient Sildenafil citrate Sildenafil citrate
Strengths sold 25mg, 50mg, 100mg 25mg, 50mg, 100mg
Action time 30 min - 1 hour 30 min - 1 hour
Duration 4 hours 4 hours
Legal Yes Yes
Price Branded - more expensive Generic - cheaper

How do I take Viagra/Sildenafil?

  • One tablet swallowed with water, one hour before you plan to have sex.
  • Only take one tablet of any strength within a 24-hour period.

Which one do I buy?

There are a couple factors that may influence which medication you choose:

Brand – It depends whether brands are important to you because both medications are medically equivalent so they will work in the exact same way. Although the tablet or the packaging may be different, as well as the name, they are both safe to use and regulated in the same way by the MHRA.

Price – Sildenafil is cheaper than Viagra as it is the unbranded medication, so it depends how much you are willing to pay for the medication.

It is worth noting that patents expire at different dates throughout the world. So, while the patent for Viagra expired in the UK in 2013, it only expires in 2020 for the US. This means that generic sildenafil is legal in the UK with a prescription, but it cannot be sold in the US until the patent has expired and no longer protects Viagra.

Iris Barbier

Written by: Iris Barbier

Pharmacy Assistant

Born in France, Iris moved to the UK to study Biological Sciences at London Metropolitan University. Upon graduating, Iris moved up north, where she completed an MA in Science Journalism at the University of Lincoln.

As a qualified science journalist, Iris uses her expertise to write content for Pharmica’s online Health Centre. She ensures our patients get specialist knowledge on medical conditions and how to treat them.


Find out more about how we ensure the accuracy of our content with our content guidelines.

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