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Cialis Vs Viagra: What’s The Difference?
Cialis Vs Viagra: What’s The Difference?
Dr. Zoë Lees (PhD)
Dr. Sophie Dix (BSc, PhD)
5 February 2015 | Updated: 4 August 2026
4 August 2026
Article Summary:
What is erectile dysfunction?
What is Cialis?
What is Viagra?
Cialis vs Viagra: how do they work?
Does Cialis work faster than Viagra?
Do you last longer with Viagra or Cialis?
Is Viagra more effective than Cialis?
Cialis vs Viagra: do they expire?
Can Cialis and Viagra be taken with food?
Which is more expensive, Cialis or Viagra?
Does Cialis have fewer side effects than Viagra?
Cialis vs Viagra: Which is better?
References
If you’re thinking of trying erectile dysfunction medication, you’ve probably heard of Cialis and Viagra, which are two of the most popular ED pills. We’re here to help you decide which one is the best treatment for you. Our experts compare Cialis vs Viagra, breaking down how fast these treatments work, how much they cost, how effective they are and more.
Article Summary:
- Cialis contains the active drug tadalafil and Viagra is the branded version of the active drug, sildenafil. Both are made to address symptoms of erectile dysfunction (ED).
- Cialis and Viagra work similarly and are two of the most common ED medications. Cialis takes effect a little faster, but Viagra stays in your body longer.
- You can take Cialis with or without food, but you should take Viagra on an empty stomach as it can take longer to work if you take it with food.
What is erectile dysfunction?
It’s not uncommon to experience erection issues, but if you keep losing erections and have trouble staying hard during sex, you could be experiencing erectile dysfunction (ED).
Erectile dysfunction is a condition characterised by difficulty achieving or maintaining an erection firm enough for penetrative sex. It’s very common, affecting 41-50% of men aged between 40 and 70 in the UK. [1]
What is Cialis?
Cialis is an erectile dysfunction treatment that contains the drug tadalafil. There are two types: Cialis and Cialis Daily. [2]
Cialis Daily is a low dose (2.5mg or 5mg) tablet you take once a day. This daily dose helps maintain a steady level of tadalafil in your bloodstream, helping you get an erection whenever you're sexually aroused. This option is ideal if you engage in sexual activity more than twice a week and prefer the spontaneity of not having to plan ahead.
You take regular Cialis as needed, typically 30-60 minutes before sexual activity. The usual dose is 10mg or 20mg, which provides a higher concentration of tadalafil in the body. This can help you achieve harder erections for up to 36 hours after taking the medication.
What is Viagra?
Viagra is one of the best-known treatments for erectile dysfunction, and it’s been used for over two decades to improve sexual performance. It's the branded version of sildenafil, which is also available as a generic tablet.
Cialis vs Viagra: how do they work?
Cialis and Viagra are also known as PDE5 inhibitors. They treat erectile dysfunction by relaxing the muscles around your blood vessels, which improves blood flow to your penis. This makes it easier to get and maintain erections when you’re aroused. PDE5 inhibitors don’t increase sexual desire, they only affect the physical side of erectile dysfunction and will only work if you are sexually aroused. [3]
Does Cialis work faster than Viagra?
Both Cialis and Viagra are fast-acting drugs and can take around 30-60 minutes to take Cialis is also available as Cialis Daily, a lower dose taken once a day, so you’re ready for sexual activity, whenever you feel aroused. [4]
Do you last longer with Viagra or Cialis?
Viagra and Cialis are used to treat erectile dysfunction, not premature ejaculation, so neither pill will help you delay climax.
Is Viagra more effective than Cialis?
Clinical evidence shows that both medications are highly effective at treating erectile dysfunction, and there’s no significant difference between the two. In clinical trials over 90% of men said Viagra improved their erections. Another study found that 81% of men had improved erections after taking Cialis.
Cialis vs Viagra: do they expire?
You should always pay attention to expiry dates; whether it’s for food and toiletries, or ED medication. Cialis has a shelf life of 3 years, while Viagra has a shelf life of 2 years. Both medications should have their expiration dates printed on the original packaging. If you’ve had your ED medication for a while, be sure to check if it's still in date and safe to use.
Can Cialis and Viagra be taken with food?
Both Cialis and Viagra are oral medications. You can take Cialis with or without food, but Viagra works best on an empty stomach, as it can take longer to work if you take it with food.
Which is more expensive, Cialis or Viagra?
It depends. The price of Cialis and Viagra depends on the dose you take, and how much you buy.
Does Cialis have fewer side effects than Viagra?
Both drugs work in the same way, which means they share many of the same common side effects. These include headaches, muscle aches, back pain, flushing and indigestion. In most cases, these settle after an hour. [5]
Contact your doctor if you experience any of these severe side effects while taking Cialis or Viagra:
- Chest pain
- Blurred vision
- Sudden hearing loss
- Fast heart rate
- High or low blood pressure
- Severe allergic reaction
Cialis vs Viagra: Which is better?
Cialis and Viagra are evenly matched at treating erectile dysfunction, improving your blood flow to help you get harder erections. [6] They both have very similar common side effects, but Cialis stays in your body for longer. Cialis is also available in two forms, daily use and on-demand, which could make it easier for you to find a dose that suits your personal needs. Both erectile dysfunction treatments need to be prescribed by a healthcare professional, and they're also available as generic medications at a lower price.
Find out what treatment is suitable for you on our website.
References
- ED In The UK - What The Statistics Say | Erectile Dysfunction [Internet]. The Independent Pharmacy. 2024. Available from: https://www.theindependentpharmacy.co.uk/erectile-dysfunction-ed/guides/ed-uk-statistics
- Dutt DM. Cialis Daily Vs Cialis | LloydsPharmacy Online Doctor UK [Internet]. Lloydspharmacy.com. 2025. Available from: https://onlinedoctor.lloydspharmacy.com/uk/erectile-dysfunction/cialis-daily-vs-cialis
- The Independent Pharmacy - The Safe & Trusted Online Pharmacy [Internet]. The Independent Pharmacy. 2025. Available from: https://www.theindependentpharmacy.co.uk/erectile-dysfunction-ed/guides/what-does-viagra-do
- How Long Does Viagra Take To Work? Expert Answer [Internet]. The Independent Pharmacy. 2019 [cited 2026 Jun 5]. Available from: https://www.theindependentpharmacy.co.uk/erectile-dysfunction-ed/guides/how-long-does-viagra-take-to-work
- Cialis vs Viagra - What’s the difference between them? [Internet]. Drugs.com. Available from: https://www.drugs.com/medical-answers/viagra-vs-cialis-3029937/
- Brewer A. What to expect when taking Cialis: A guide about side effects [Internet]. Medicalnewstoday.com. Medical News Today; 2021 [cited 2026 Jun 3]. Available from: https://www.medicalnewstoday.com/articles/drugs-cialis-side-effects#more-common-side-effects
Next scheduled review date: 4 August 2029
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Authors
Written by: Dr. Zoë Lees (PhD)
Dr. Zoë Lees is a medical writer at MedExpress specialising in obesity and health communication. She completed her PhD at the University of Glasgow, where she investigated adipose tissue (fat tissue) function in pregnancies complicated by pre-eclampsia and gestational diabetes. Her work focuses on translating complex clinical evidence into clear, engaging and evidence-based health information for patients and the public. At MedExpress, Zoë contributes to clinical content, educational resources and media communications across areas including weight management, GLP-1 therapies and metabolic disease. Zoë is particularly interested in improving public understanding of obesity as a chronic condition and ensuring patients have access to accurate, accessible health information grounded in current scientific evidence.
Medically reviewed by: Dr. Sophie Dix (BSc, PhD)
Dr. Sophie Dix is Head of Medical Affairs at MedExpress. A behavioural neuroscientist by training, Sophie has spent 30 years working at the intersection of medical research, pharmacology, technology and patient communication across the pharmaceutical industry, health technology and charity sectors. At MedExpress, Sophie's role is to ensure that everything the organisation does is grounded in the most current science. That means translating complex clinical evidence into accessible health information across the website, clinical pathways and media communications. It also means working with external press and broadcast media as a named expert commentator, making the science behind weight management and GLP-1 treatments understandable to a general audience. A core part of Sophie's work is building MedExpress's Real-World Evidence (RWE) programme: learning systematically from patient outcomes to understand what works in practice, not just in clinical trials. This patient-level insight feeds directly into improving patient experience and health outcomes. Sophie believes that patients make better decisions when they have access to accurate, evidence-based information. As an advocate for meaningful change in how obesity is understood, Sophie works to reduce stigma and raise awareness of the condition as an illness. This includes reframing the conversation around GLP-1s from aesthetics to public health, while highlighting the health benefits of weight loss and weight management.
Note from the experts
Remember: This blog shouldn’t be regarded as medical advice, diagnosis, or treatment. We make sure everything we publish is fact checked by clinical experts and regularly reviewed, but it may not always reflect the most recent health guidelines. Always speak to your doctor about any health concerns you have.