Weighing up your options for erectile dysfunction or ED treatment? This blog compares sildenafil (Viagra) and tadalafil (Cialis) in plain English—how they work, how long they last, side effects, lifestyle tips, and expert answers to your most-asked questions. Read on for everything you need to know to make the right choice for you.
Table of contents
- Key takeaways:
- Introduction: Why does the choice between sildenafil and tadalafil matter?
- What is erectile dysfunction?
- What are sildenafil and tadalafil?
- How do sildenafil and tadalafil work?
- How long does it take for sildenafil and tadalafil to work?
- Which lasts longer: sildenafil or tadalafil?
- Which is more effective sildenafil or tadalafil?
- Side effects: What should you expect with sildenafil and tadalafil?
- How do you take sildenafil and tadalafil?
- Can you take sildenafil or tadalafil every day?
- Food, alcohol, and other interactions with sildenafil and tadalafil
- Who shouldn’t take sildenafil or tadalafil?
- Real-world tips for choosing between sildenafil vs tadalafil
- Frequently asked questions (FAQs)
- Conclusion: Which one is right for you?
- Fast and Longer-Lasting? Meet the ED Combo Patch from Courier Pharmacy
- How this content was created
- References:
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Tadalafil 20mg tabletsPrice range: £8.99 through £32.99
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Tadalafil 5mg tabletsPrice range: £17.99 through £45.99
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Sildenafil 100mg TabletsPrice range: £6.99 through £69.99
Key takeaways:
- Both sildenafil and tadalafil are effective and safe treatments for erectile dysfunction, but differ in how long they last and how quickly they work.
- Sildenafil (the “blue pill”) acts fast but lasts 4–6 hours; tadalafil (the “weekend pill”) can work for up to 36 hours.
- Food and alcohol can affect how well these medicines work—sildenafil is best on an empty stomach, while tadalafil is more flexible.
- A compounded combination buccal film is available only from Courier Pharmacy for those who need the flexibility of a faster but longer-acting ED preparation.
- Your lifestyle, preferences, and health conditions should guide your choice—this guide will help you decide.

Introduction: Why does the choice between sildenafil and tadalafil matter?
Let’s be honest: erectile dysfunction (ED) isn’t the easiest topic to talk about. But you’re not alone—millions of men in the UK experience it at some point, and there’s no shame in wanting to do something about it [1]. The good news? Modern medicine has provided us with reliable and safe options. The challenge is figuring out which one fits your lifestyle the best.
This blog is your no-nonsense, friendly guide to sildenafil and tadalafil. We’ll break down the science, share real-world advice, and answer the questions most men have (but don’t always ask). Whether you want to plan ahead or keep things spontaneous, you’ll find what you need to know right here.

What is erectile dysfunction?
Erectile dysfunction is when you cannot get or maintain a firm enough erection for satisfying sex [1].
The number of men with erectile dysfunction or ED is increasing, and it is thought that the figure could be approaching 322 million [2].

What causes erectile dysfunction?
ED is a plumbing issue. When the pipes become damaged, it’s harder for blood to flow into them to cause an erection.
Chronic erectile dysfunction is linked to heart problems like clogged arteries, high blood pressure, and diabetes [3]. Because of this, ED is like the canary in the mineshaft, warning us that something is wrong with our blood vessels [4].
Low testosterone is also another cause of ED [5].

What are sildenafil and tadalafil?
Sildenafil and tadalafil are both prescription medicines for ED. They belong to a group called PDE5 inhibitors, which help blood flow to the penis when you’re aroused [6].
Sildenafil is most famous as Viagra, the “little blue pill.” Tadalafil is known as Cialis, often referred to as the “weekend pill” due to its effects lasting up to 36 hours [7].
Both have been proven safe and effective for most men [1], [6]. They won’t cause an erection unless you’re sexually aroused—so no awkward surprises during your weekly shop.

How do sildenafil and tadalafil work?
Think of your blood vessels as garden hoses. When you’re aroused, your brain tells your body to increase blood flow to your penis. PDE5 inhibitors like sildenafil and tadalafil block the enzyme PDE5, keeping those “hoses” open and making it easier to get and maintain an erection [8].
But here’s the catch: you still need to be in the mood. These medicines only work if you’re sexually stimulated—they’re not magic, just a helping hand.
The main difference? How quickly they work and how long they last.

How long does it take for sildenafil and tadalafil to work?
Sildenafil:
Usually takes effect in 30–60 minutes [9]. For best results, take it on an empty stomach—fatty foods can slow it down [10]. Effects last about 4–6 hours, though you might notice a little extra “oomph” for up to 24 hours [9].
Tadalafil:
Kicks in after about 30–60 minutes, too, but can be taken with or without food. The real star feature? Tadalafil can last up to 36 hours—hence the “weekend pill” nickname [11].
So, if you want a quick, predictable effect, sildenafil is a classic. If you prefer a longer window and more flexibility, tadalafil could be your new best friend.

Which lasts longer: sildenafil or tadalafil?
With tadalafil, you don’t have to rush—take it in the morning and you’re good to go the next day (or even the next night).

Which is more effective sildenafil or tadalafil?
Both drugs are highly effective, with studies showing success rates of 60–70% for most men [12], [13]. Some men find one works better than the other, so if you don’t get the results you want the first time, talk to your doctor or pharmacist about trying the other [6].
Effectiveness can depend on your health, other medicines, and even what you’ve eaten that day [1],[8].

Side effects: What should you expect with sildenafil and tadalafil?
No medicine is perfect, and PDE5 inhibitors are no exception. Here’s what you might notice:
- Sildenafil: Headache, flushing, indigestion, stuffy nose, and sometimes a blue tinge to your vision[14].
- Tadalafil: Similar side effects, but some men get back pain or muscle aches. Blue vision is less common with tadalafil [15], [16].
Serious side effects are rare, but if you get chest pain, sudden vision or hearing loss, or an erection lasting longer than four hours (priapism), get medical help right away [1].

How do you take sildenafil and tadalafil?
- Sildenafil: Take one tablet about an hour before sex. It works best on an empty stomach, and you shouldn’t take more than one in 24 hours [9].
- Tadalafil: Can be taken as needed (one tablet at least 30 minutes before sex, effects last up to 36 hours) or as a daily low-dose tablet (so you’re always ready). Follow your doctor’s instructions and never exceed the recommended dose [17].

Can you take sildenafil or tadalafil every day?
Sildenafil is designed for “as-needed” use. Tadalafil is also available as a when required form when taken as a tadalafil 10mg or tadalafil 20mg tablet. However, it also comes in low-dose options of tadalafil 2.5mg and tadalafil 5mg tablets, which means you can be ready at any time without planning [18]. This can be great for couples who want more spontaneity and less pressure.

Food, alcohol, and other interactions with sildenafil and tadalafil
- Sildenafil: Works best on an empty stomach. High-fat meals can slow it down. Alcohol can make it less effective and increase side effects [19].
- Tadalafil: Can be taken with or without food. Alcohol can still lower effectiveness and increase side effects—so moderation is key [20].
Both drugs can interact with nitrates (for chest pain), some blood pressure medicines, and other medications [1], [6]. Always inform your pharmacist or doctor about all the medications you’re taking.

Who shouldn’t take sildenafil or tadalafil?
You should avoid PDE5 inhibitors if you:
- Take nitrates for chest pain (risk of dangerous blood pressure drop)
- Have serious heart or liver problems
- Have had a recent stroke or heart attack
- Have very low blood pressure or certain rare eye diseases
Always tell your healthcare provider about your full medical history. No question is too small when it comes to your health [1], [6].

Real-world tips for choosing between sildenafil vs tadalafil
- Timing: Prefer flexibility or don’t want to plan? Tadalafil’s long window is a big plus.
- Side effects: If sildenafil gives you headaches or blue-tinged vision, tadalafil might suit you better [16].
- Lifestyle: Want a pill only when needed? Sildenafil is a classic. Want to be ready any time? Tadalafil’s daily option could be ideal.
- Cost: Both are available as affordable generics. Courier Pharmacy offers competitive prices and discreet delivery.

Frequently asked questions (FAQs)
1. What’s the main difference between sildenafil and tadalafil?
The main difference is how long they last. Sildenafil works for 4–6 hours, while tadalafil can last up to 36 hours.
2. Can I take sildenafil or tadalafil with alcohol?
A little alcohol is usually OK, but too much can make both drugs less effective and increase side effects [21].
4. Can I take these medicines if I have other health conditions?
It depends. Always consult your doctor or pharmacist about your medical history and any other medications you’re taking.
5. Will sildenafil or tadalafil give me an instant erection?
No—they only work if you’re sexually aroused.
6. Are there any serious risks with these medicines?
Serious side effects are rare but can include chest pain, sudden vision or hearing loss, or a prolonged erection. Seek medical help immediately if these symptoms occur.
7. Can I take sildenafil and tadalafil together?
You can only take both together if you opt for Courier Pharmacy’s Combo ED patch. This buccal film, which you place on the inner cheek, contains sildenafil, tadalafil and L-arginine. So, you get a faster and longer-acting ED solution.
8. Is one medicine better for long-term use?
Tadalafil is available as a daily low-dose tablet for ongoing use. Sildenafil is for occasional use only.
9. Is there a big price difference?
Both are available as affordable generics, and so both are relatively cheap. Courier Pharmacy offers both at very competitive prices in the UK. All you need to do is complete the online consultation form.
10. Where can I get more advice?
Erectile dysfunction shouldn’t be a taboo subject—it can act as an early warning sign of underlying vascular or psychological concerns.
At Courier Pharmacy, we’re here to support you. If standard PDE5 inhibitors haven’t worked for you or you’re looking for a more personalised treatment plan, we’re ready to help. Taking that first step can make all the difference, so feel free to reach out with any questions or concerns.

Conclusion: Which one is right for you?
When it comes to sildenafil vs tadalafil, the best choice depends on your lifestyle, preferences, and health.
Both are safe and effective when used as prescribed, and both can help restore confidence and intimacy.
If you can’t decide, why not try both by using the Courier Pharmacy ED combo patch? Read on for more information.

Fast and Longer-Lasting? Meet the ED Combo Patch from Courier Pharmacy
Looking for a more flexible approach to managing erectile dysfunction?
The ED Combo Patch is a compounded prescription patch, prepared to order and designed for rapid absorption through the inside of your cheek.
It combines fast-acting sildenafil, longer-lasting tadalafil (up to 36 hours), and L-arginine to support healthy blood flow—all in one patch.
- May start working in as little as 15–30 minutes
- Effects can last up to 36 hours
- No tablets to swallow—just simple, discreet support
The ED Combo Patch is an unlicensed, compounded medicine supplied only on prescription when licensed alternatives may not be suitable. Your prescriber will help you decide what’s right for you. All treatments follow MHRA safety guidance.
Find out more or ask your pharmacist today. Always discreet, always professional
How this content was created
This article was written by Shazlee Ahsan, Superintendent Pharmacist, and reviewed by our clinical team. We used up-to-date research from the NHS, NICE, peer-reviewed journals, and patient experiences from Courier Pharmacy and Medical Mojo. All information is intended for general guidance—always check with your healthcare professional for personal advice.
This information is for general guidance only. For advice about your health, please talk to your doctor or healthcare provider.

References:
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- Ayta IA, McKinlay JB, Krane RJ. The likely worldwide increase in erectile dysfunction between 1995 and 2025 and some possible policy consequences. BJU Int. 1999 Jul;84(1):50-6
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- Montorsi F, Briganti A, Salonia A, et al. Erectile dysfunction prevalence, time of onset and association with risk factors in 300 consecutive patients with acute chest pain and angiographically documented coronary artery disease. Eur Urol. 2003;44:360–4.
- Medical Mojo (n.d.) What is TRT? Available at: https://medicalmojo.co.uk/what-is-trt/ (Accessed: 7 March 2025).
- NICE Clinical Knowledge Summaries (2023) Erectile dysfunction: Phosphodiesterase-5 (PDE-5) inhibitors. Available at: https://cks.nice.org.uk/topics/erectile-dysfunction/prescribing-information/phosphodiesterase-5-pde-5-inhibitors/ (Accessed: 15 July 2025).
- Courier Pharmacy (2024) How long does tadalafil 20mg last after taking it? Available at: https://courierpharmacy.co.uk/how-long-does-tadalafil-20mg-last-after-taking-it/#h-how-long-does-tadalafil-20mg-last-after-taking-it (Accessed: 15 July 2025).
- Medical Mojo (2024) Viagra vs Cialis: What’s the difference? Available at: https://medicalmojo.co.uk/viagra-vs-cialis/#h-how-is-an-erection-caused (Accessed: 15 July 2025).
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- Nichols, D.J., Muirhead, G.J. and Harness, J.A., 2002. Pharmacokinetics of sildenafil after single oral doses in healthy male subjects: absolute bioavailability, food effects and dose proportionality. British journal of clinical pharmacology, 53, pp.5S-12S.
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- Goldstein, I., et al. (2019). Oral sildenafil in the treatment of erectile dysfunction. The New England Journal of Medicine, 338(20), 1397-1404.
- McMahon, C.G. (2019). Comparison of efficacy, safety, and tolerability of sildenafil and tadalafil in men with erectile dysfunction: A systematic review. International Journal of Impotence Research, 31(1), 1-13.
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- Medical Mojo (2024) Viagra vs Cialis: Which one is better for you? Available at: https://medicalmojo.co.uk/viagra-vs-cialis/#h-cialis-does-not-affect-blue-vision (Accessed: 15 July 2025).
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- Medical Mojo (2024) When to take Tadalafil – What is Tadalafil daily?. Available at: https://medicalmojo.co.uk/when-to-take-tadalafil/#h-what-is-tadalafil-daily (Accessed: 15 July 2025).
- Medical Mojo (2024) How long does Sildenafil last for – Can I take Sildenafil with food?. Available at: https://medicalmojo.co.uk/how-long-does-sildenafil-last-for/#h-can-i-take-sildenafil-with-food (Accessed: 15 July 2025).
- Medical Mojo (2024) How long does Tadalafil last after taking it – Tadalafil and fatty meals. Available at: https://medicalmojo.co.uk/how-long-does-tadalafil-last-after-taking-it/#h-tadalafil-and-fatty-meals (Accessed: 15 July 2025).
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