How Quickly Does Viagra Work, and How Long Does it Last?

Brenda Ikeji

Medically reviewed by

Dr Brenda Ikeji

Last reviewed: 23 Feb 2025

Viagra is one of the most popular erectile dysfunction (ED) medications in the UK. It works by increasing blood flow to the penis, helping you to get and keep an erection when you’re sexually aroused.

If you’re considering taking Viagra, Viagra Connect, or any other tablets containing sildenafil, knowing what to expect when you first start treatment can help you feel more prepared and at ease before trying it out. In this guide, we discuss how long Viagra takes to work, how long it lasts, and our top tips for getting the best results.

Contents
Man lying in bed checking on his phone for how quickly Viagra starts working
 

Key takeaways

  • The average time for Viagra to start working is 30 to 60 mins

  • Viagra won't cause an erection on its own, and you need to be sexually aroused for it to work

  • Avoid heavy meals before taking Viagra so you don't slow it down

  • Viagra usually lasts 4 to 6 hours

  • Taking more than 1 Viagra a day is unsafe and won't make it work any faster

How does Viagra work?

The active ingredient in Viagra is sildenafil. Sildenafil is part of a group of medicines called phosphodiesterase-5 inhibitors (PDE5) which work by increasing the blood flow to the penis, making it easier to get an erection. Still, Viagra doesn’t cause erections directly, you must be sexually aroused for it to work.

How Viagra (sildenafil) works:

  • a chemical called PDE5 helps blood vessels around the penis tighten, which stops extra blood entering the penis when it’s not needed
  • when you have erectile dysfunction, you don’t need as much PDE5 in the penis because it stops enough blood flowing in for you to get a proper erection
  • Viagra makes the effect of PDE5 less strong for about 4 to 6 hours, so blood flows into your penis more easily than normal, making erections easier to get and keep
  • this is why medications like Viagra are called PDE5-inhibitors

Viagra works for around 3 out of 4 men who try it, but it can take a few tries before you see the full effect when taking it for the first time. Later on, we explore tips for how to help Viagra work better, and how to take it properly.

How long does it take for Viagra to work?

Viagra is usually thought of as a ‘fast-acting’ drug, which means that it enters your system and starts working fairly quickly.

The average time for how long it takes Viagra to kick in is 30 to 60 minutes. Results vary from person to person, so it could happen for you faster than 30 mins, or slower than 60.

Below are the average timelines for how Viagra works in your body:

what happens after taking Viagra step by step from 0 minutes to 4 to 6 hours

Does Viagra make you hard right away?

No. Viagra doesn’t give you an erection on its own. It enhances blood flow to the penis, but sexual arousal is still required for it to work. Think of it as a support, not an automatic trigger – engaging in foreplay or sexual stimulation is still necessary to achieve an erection while taking Viagra.

How long does Viagra last?

How long the effects of Viagra last varies from person to person, but it usually works for around 4 to 6 hours on average. It can stop working earlier or last longer depending on how quickly your body metabolises the medication. When taken as instructed, here’s how long Viagra works for:

On average, erections with Viagra last for:

  • 33 mins, 1 hour after taking Viagra
  • 23 mins, 8 hours after taking Viagra
  • 16 mins, 12 hours after taking Viagra

How long Viagra stays in your body:

  • After 1 hour: Viagra reaches the maximum level in your body
  • After 4 hours: There is still around 50% of the maximum level of Viagra still in your body
  • After 8 hours: There is only around 10% of the maximum level of Viagra left in your body
  • After 24 hours: All the Viagra in gone from your body and you can take another dose of Viagra again

How long Viagra lasts doesn’t change very much based on the strength of the medication. For example, there’s no significant difference between how long 100mg of Viagra lasts compared to 50mg.

How can you get the best results from Viagra?

Viagra only lasts for around 4 to 6 hours on average, unlike other drugs like Cialis – which last around 36 hours. How your body responds to the medication and how long sex lasts with Viagra is different for everyone.

Although it’s a fast-acting medication, it still takes time to get absorbed by your body. You can’t make Viagra work faster, but there are a few things you can do to ensure you’re not slowing it down:

  1. Take Viagra on an empty stomach or after a light meal. Eating heavy meals or fatty foods can delay the absorption of Viagra and slow down its effects.
  2. Avoid alcohol. Even though alcohol can help you relax before sex, it can affect how well Viagra works.
  3. Avoid grapefruit or grapefruit juice as it can increase the drug’s concentration in your blood, affecting how it works and increasing your risk of side effects.
  4. Ensure you’re in a safe, comfortable space where you can naturally become sexually aroused. Consider using an erection-enhancement device like a penis pump or ring to help make this easier.

Remember:

  • Viagra doesn’t always work the first time, and you might need to try it up to 8 different times to see the full effect
  • Viagra doesn’t work for everyone and if it still hasn’t worked after a few tries, you might want to think about a higher dose or another ED medication

Tip: If you’re worried about Viagra not getting to work in time for sex, you could try testing out how long it takes for you to get an erection with Viagra on your own first. Once you know how long it takes for you, then you could try it out with a partner and be able to time it better.

What else can affect how well Viagra works?

Like any medication, certain lifestyle and physiological factors can affect how quickly Viagra works and how long the effects last. These include:

1. Age and BMI: Age can influence how Viagra is broken down in the body, with older males (65+) sometimes experiencing slower onset times. If your body mass index (BMI) is higher than average, you may also notice that the medication takes slightly longer to work.

2. Health conditions and medications: Pre-existing conditions like diabetes, high blood pressure, or heart disease may reduce blood flow or interfere with how well Viagra is absorbed. Certain medications, such as those prescribed for high blood pressure or prostate issues, can also interact with Viagra, impacting its effectiveness.

3. Mental and physical wellbeing: Stress, anxiety, and other psychological factors can sometimes cause issues with arousal. Addressing these issues, whether through relaxation techniques, counselling, or small lifestyle changes, can improve your overall ED management. Additionally, maintaining a healthy lifestyle through regular exercise, good sleep, and weight management can enhance Viagra’s benefits and improve your ED symptoms.

Dr Brenda Ikeji, medical editor and GP

“When you request treatment for erectile dysfunction, your GP or online doctor will assess factors like your weight and any pre-existing health conditions. They will help to decide whether Viagra is the right treatment for you, and advise you on the correct dosage for your personal needs. Your doctor can also advise you on any lifestyle changes that may be necessary to help improve symptoms of ED.” Dr Brenda Ikeji, Medical Editor.

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How do I take Viagra?

You should always take Viagra as instructed by your doctor, or according to the guidelines inside the patient information leaflet that comes with the medication.

Here’s what to keep in mind:

  1. Take a tablet roughly 30 minutes before trying to have sex.
  2. Ideally, take your Viagra pill with a sip of water, and avoid heavy meals.
  3. Only take one tablet in the same 24-hour period.

If you don’t get results after 1 hour, it’s important not to take another tablet, as this can be dangerous. Taking extra pills won’t have any effect on how fast it works, and you’ll be putting yourself at risk of serious side effects.

How often should Viagra be taken?

Viagra should only ever be taken once a day. It’s not safe to take another one before the 24-hour mark, even if you aren’t feeling the effects any more. This is because there will still be some Viagra left in your system so you could raise the amount of Viagra in your body above a safe level.

Even if you’re taking less than the maximum daily dose of Viagra (100mg), you still shouldn’t take extra Viagra on the same day because you need a doctor to check if a higher dose is safe for you first. If you want to increase your dose, you can use an online doctor service like ZAVA, or check with your GP.

There is no evidence that taking Viagra long-term causes any lasting health problems or that Viagra stops working as well the longer you take it. So, Viagra can be used as a long-term treatment for erectile dysfunction, but it might be a good idea to think about other treatment options that can improve your erections in the long-term too. These can include lifestyle changes, pelvic floor exercises, or counselling.

If you’ve taken Viagra and are experiencing a painful erection that lasts more than 2 hours or an erection that won’t go away after 4 hours, please seek medical attention right away.

What alternatives are there to Viagra?

If Viagra isn’t working for you, or your doctor has advised that it may not be suitable for you, there are a few good alternatives to Viagra that you can try. In particular, some have less or no time to take effect compared to Viagra.

Spedra (avanafil):

Cialis (tadalafil):

  • can start to work within 30 minutes
  • can last for up to 36 hours (this is why it’s also known as the ‘weekend pill’)
  • still recommended that you take it 1 hour before sex

Cialis Daily:

  • lower dose than Cialis that you take every day
  • takes around 3 days to build up to a steady level in your body
  • once it’s at the right level, you should be able to get erections easily and at any time, so you don’t have to plan for sex
  • best option if you have sex on more than 2 days a week

It’s also worth mentioning that if you fix the underlying causes of ED, you could make it easier to get erections any time (a bit like if you were using Cialis Daily). You can do this by:

  • making lifestyle changes
  • getting counselling if there could be a psychological reason for your symptoms
  • getting checked for related health conditions that can cause ED
  • getting your other medications checked in case they’re causing ED as a side effect

Alternative medication for erectile dysfunction should always be regulated and recommended by doctors. Sildenafil-containing products like Kamagra and Kamagra Oral Jelly may work differently and cause severe side effects.

Conclusion

Viagra is an effective treatment for erectile dysfunction that starts working after 30 to 60 minutes and lasts around 4 to 6 hours. However, getting the best results depends on using it correctly. If it doesn’t work perfectly the first time, don’t worry, you may see improvements after a few tries, and there are alternative medications available if it’s not right for you.

For personalised advice or to explore other treatments, speak to your doctor to discuss your options. ZAVA is here to provide expert support and convenient access to the right erectile dysfunction medications for you.

FAQs about how Viagra works

Does Viagra keep you hard after you come?

Viagra can help you maintain improved erectile function for several hours, but it won’t keep you hard immediately after ejaculation. A refractory period – the time it takes your body to recover before another erection is possible – is still required, and this varies from person to person.

Can you get hard a second time with Viagra?

Yes, Viagra may make it easier to achieve multiple erections during its 4 to 6-hour effective window, as long as you’re sexually stimulated. However, the refractory period still applies, so how quickly you can get an erection again depends on your response and factors like age, health, and arousal.

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Medically reviewed by:
Dr Brenda Ikeji Medical Editor

Brenda studied medicine at St Georges University of London and has most recently worked in John Radcliffe Oxford University Hospitals, covering acute and general medicine.

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Last reviewed: 23 Feb 2025





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