How long does Viagra last? How long does it take for it to work?

How long does Viagra last? How long does it take for it to work?
Medically approved by
Dr Earim Chaudry
Last updated
15th July 2020

Erections aren’t always easy for millions of men in the UK. It’s no big deal. Choose from highly effective, clinically proven solutions.

In 30 seconds…

The little blue pill, AKA Viagra, usually gets to work 30–60 minutes after taking, with maximum erection potential at the 1 hour mark. Most men experience the active effects for up to 4 hours.

Viagra is less effective when taken with or after a heavy, high-fat meal, so to enjoy the full benefits it needs to be taken on an empty stomach or with a light snack.

To achieve an erection after taking Viagra, you’ll need to get sexually aroused – the pill can’t do everything on its own!

Viagra (or Sildenafil): How long does it take to work?

When you’re looking into treatments for ED (erectile dysfunction), it’s natural that you want to know how long your chosen drug will take to kick in – and how long you can enjoy its effects for. These are considerations that will impact your sex life and your relationship with your sexual partner – so of course you want to be fully-informed.

The best-known drug used to treat ED is Viagra, but in fact you can also take an alternative pill in the form of Viagra’s active ingredient, Sildenafil, as a generic (non-branded) tablet. There’s no medical difference between the two drugs – it’s all in the name. So everything we say about the effects of Viagra in this article is also true of Sildenafil, and vice versa.

Sildenafil works by relaxing the walls of the blood vessels in the penis, letting blood flow in more easily so you can achieve an erection. It usually takes 30-60 minutes for the drug to be fully-effective. That doesn’t mean you’ll automatically get an erection though – you’ll still need to be sexually aroused for this to happen.

How long does Sildenafil last?

The best time to get an erection with Sildenafil is typically 1 hour after taking it. Most men experience the active effects of the drug for 2-3 hours, but they may last as long as 4-6. What happens is that the amount of the drug present in your body roughly halves every 4 hours, so by the time 24 hours have passed, it’s completely gone from your system.

During the active period of the drug, with sexual stimulation, you should be able to maintain an erection that is firm enough to enjoy sex to the full. You may even find it possible to achieve several erections in that time.

Viagra (Sildenafil)

The little blue pill

It’s the active ingredient in Viagra. MHRA approved and clinically proven to be highly effective by increasing blood flow into the penis.


Best for
One off use
Effective in
8 out of 10 men
Dosage
50 to 100mg

What factors impact the effectiveness of Sildenafil?

There are a number of external factors that may make Sildenafil slower to work or less effective:

Food: Eating a heavy meal, particularly one with lots of high-fat foods, just before taking Sildenafil can make the drug slower to take effect. The body takes longer to absorb the drug when it’s busy metabolising food.

Grapefruit juice: Unfortunately for you fans of citrus fruit, grapefruit juice should be avoided when taking Sildenafil. Drinking it can increase the amount of drug in your bloodstream, making side effects more likely.

Alcohol: Drinking alcohol has a negative impact on blood flow to the genitals, so it reduces the effectiveness of Sildenafil (which is trying to increase blood flow to help you achieve an erection). Alcohol also raises the risk of experiencing side effects from the drug.

Age: Older men (over 65 years old) might experience the active effects of Sildenafil for longer than the typical 2–3 hours. As you age, your metabolism slows down, so the drug is absorbed more slowly into your body. 

Overall health: Certain health conditions, such as diabetes, MS and some heart conditions, can exacerbate erectile dysfunction. It’s important these are treated and controlled, whenever you look to address an ED problem. 

Other medications: Taking certain other medications at the same time as Sildenafil can impact its effectiveness – so it’s important to make any clinician aware of what treatments you are taking. You should never take Sildenafil alongside other ED medications.

Mental/emotional wellbeing: Many men experience worry and performance-anxiety when beginning ED treatment for the first time, and this is completely natural. So for some men additional support such as counselling might be necessary to maximise treatment success. 

In case Sildenafil doesn’t work perfectly the first time, don’t panic as it’s important to assess its effectiveness over a period of time. Your clinician will help you decide whether you should persevere with the drug, try a higher dose, or choose an alternative treatment.

Important note: Taking more than your prescribed dose of Sildenafil is dangerous, and can potentially cause priapism (a painful constant erection that lasts longer than 4 hours). If this does occur, seek emergency medical treatment.

Tadalafil: The “weekend pill”

One alternative medical treatment for ED is Tadalafil. It’s the active ingredient in the brand-name drug Cialis. Just like Sildenafil, Tadalafil takes around 30 minutes to kick in, and the maximum potential for an erection is about 2 hours after taking. However, it remains active in your body for much longer than Sildenafil – 24-36 hours – earning its nickname, the “weekend pill”. 

So if you and your partner are looking for more spontaneity, Tadalafil provides a wider window of opportunity for sex. 

Tadalafil and Sildenafil are from the same family of drugs – PDE5 inhibitors – so they are affected by similar external factors but they just work for different durations of time. Another key difference is that Tadalafil is not affected by food, so you can take it and enjoy that romantic dinner without finding it delays the onset of action of the drug.

Cialis (Tadalafil)

The weekend pill

Known as the “weekend pill” because it is effective for up to 36 hours, Tadalafil is the generic, unbranded version of Cialis. Clinically proven to help you get an erection when you need it.


Best for
Weekend use
Effective in
Effective in 8 out of 10 men
Dosage
2.5mg, 10mg, 20mg

Key Takeaways…

How long Viagra (or Sildenafil) takes to kick in will always depend to some extent on your own body – how it reacts to the drug. However, most men can expect to achieve an erection that is firm enough and lasts long enough to enjoy sex 30-60 minutes after taking the tablet, with enough sexual stimulation. 

Sildenafil typically stays active in your body for up to 4 hours, so sex does take some planning! If you prefer greater spontaneity in your sex life, Tadalafil is an effective, longer-lasting alternative to consider.

ED doesn’t have to stop you from enjoying yourself. Finding the right treatment is all it takes to get back to a fulfilling sex life.

Erections aren’t always easy for millions of men in the UK. It’s no big deal. Choose from highly effective, clinically proven solutions.

While we've ensured that everything you read on the Health Centre is medically reviewed and approved, information presented here is not intended to be a substitute for professional medical advice, diagnosis, or treatment. It should never be relied upon for specific medical advice. If you have any questions or concerns, please talk to your doctor.

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