How long does Sildenafil take to work?

Erectile dysfunction (ED) affects millions of men worldwide, and Sildenafil is one of the most popular and effective treatments. But how long does Sildenafil take to work? How long does Sildenafil last? And when is the best time to take the drug?

In this article, we’ll answer these common questions about Sildenafil and see how its effects and duration compare to other erectile dysfunction treatments.

What does Sildenafil do?

Sildenafil—better known by the brand name Viagra—is a medication specifically designed to treat ED. It works by increasing blood flow to the penis, making it easier to achieve and maintain an erection when sexually aroused.

Sildenafil belongs to a group of medications known as PDE-5 inhibitors. The active ingredient is a compound called Sildenafil citrate, which blocks an enzyme called phosphodiesterase type 5 that restricts blood flow. By inhibiting this enzyme, Sildenafil helps relax blood vessels in the penis, allowing for improved circulation and firmer, stronger, and longer-lasting erections.

Keep in mind that Sildenafil tablets don’t cause spontaneous erections—they enhance your natural response to sexual stimulation, allowing for a more satisfying experience. You won’t get an erection after taking Viagra without this stimulation; you need the drug and arousal for the drug to work.

How long does Sildenafil take to kick in?

Sildenafil pills generally take 30 to 60 minutes to start working (1). For most men, the drug reaches peak effectiveness within one hour of ingesting it. However, all men are different. Some may notice effects as quickly as 12 minutes after taking the medication (2).

We see this variation between individuals because factors such as metabolism and overall health can impact how quickly Sildenafil citrate enters the bloodstream—and the faster the drug is absorbed into the blood, the quicker it starts to work. For example, the absorption rate is usually slower if you have a slower metabolism or a higher body weight.

Eating high-fat meals before taking Sildenafil tablets can also mean it takes longer for their effects to kick in. When fasting, Sildenafil citrate reaches peak concentrations in the blood in around 30 minutes, whereas this peak is delayed to four hours after a high-fat meal (3). This means the full effects of the medication can be delayed, depending on what you’ve eaten.

How long does Sildenafil last?

On average, the effects of Sildenafil for men with ED last between 4 to 6 hours. During this time, you should be able to achieve and maintain an erection as long as you’re sexually aroused. However, the duration of Sildenafil’s effects can vary based on several factors:

• Metabolism: People with fast metabolisms can process drugs more quickly. If you have a faster metabolism, the effects of Sildenafil tablets may wear off sooner, whereas a slower metabolism can mean the effects of the drug last longer.
• Dosage: Sildenafil pills come in various doses. Higher doses, such as Sildenafil 100mg, may have a longer-lasting effect than lower doses of 25mg. Sildenafil 50mg is the starting dose, adjusted up or down based on your response to the drug.

It’s important to know that higher doses of Sildenafil don’t necessarily mean better results or stronger erections. In fact, it’s essential to stick to the prescribed dosage, as higher doses can increase the risk of Sildenafil side effects, such as headache, heartburn, nausea, diarrhea, and nosebleeds.

If you want more information on how long the drug lasts, you can find out in our article: How long does Sildenafil last?

When should I take Sildenafil for the best results?

Most men are advised to take one Sildenafil tablet around 1 hour before they want to have sex (4). However, because Viagra usually kicks in around 30 minutes after being taken and lasts up to four hours, it should still be effective if taken any time within this window.

As mentioned, eating heavy meals beforehand delays how quickly the drug enters the bloodstream, so it’s usually recommended to take Sildenafil pills on an empty stomach. Research studies have also found that taking Viagra with food doesn’t make the medicine any less effective, so taking a Sildenafil tablet with a meal is another option (5).

How does Sildenafil compare to other ED treatments?

While Sildenafil for men with erectile dysfunction is a popular option, there are other ED treatments available. All drugs are processed differently, and each type of treatment has its own window within when it’s effective. Here’s a quick comparison:

Tadalafil vs Sildenafil

Tadalafil is another PDE-5 inhibitor. It can start working within as little as 15 minutes, but the effects of the drug may not peak around 2 hours after taking the drug (6). This variation is similar to what you can expect with taking Sildenafil, and it’s usually recommended to take the drug at least 30 minutes before you plan to have sex.

The main difference between tadalafil vs Sildenafil is how long the drugs last. Tadalafil tends to last longer, with effects lasting up to 36 hours (7). This makes it a preferred option for men who desire a longer window of effectiveness (8).

Vardenafil vs Sildenafil

Similar to Sildenafil citrate, vardenafil is another PDE-5 inhibitor and takes about 30 to 60 minutes to start working. Its effects typically last around 4 to 5 hours, around the same length of time that the effects of Sildenafil tablets last (9).

However, one of the benefits of vardenafil is its fewer interactions with food. One study compared the effects of vardenafil when taken after fasting, after a high-fat breakfast, on an empty stomach, and after a moderate-fat dinner. The peak levels of the drug remained fairly consistent, and taking it after a high-fat breakfast only delayed the time it took for the drug to kick in by around 1 hour (10).

Avanafil vs Sildenafil

Avanafil is another PDE-5 inhibitor known for its fast onset. The drug is rapidly absorbed into the bloodstream, reaching peak levels 30 to 45 minutes after being taken (11). Men can get and keep erections within 20 to 40 minutes, and some studies have found that successful sex was possible within as little as 15 minutes (11).

In terms of how long the effects last, avanafil lasts up to 6 hours (12)—around the same time you can expect a Sildenafil tablet to work. However, the fact the drug kicks in so quickly is hugely beneficial, allowing you to be more spontaneous with your partner.

Can you buy Sildenafil online over the counter?

In the UK, Sildenafil tablets are available both by prescription as Viagra and generic Sildenafil pills and over the counter under the name Viagra Connect or Eropid (13).

When buying over the counter, you don’t need a doctor’s prescription, but you do need a consultation with a pharmacist. You can do this in person at your local pharmacy or buy Sildenafil online at registered online pharmacies by filling in an online health questionnaire.

Over-the-counter Sildenafil is only available in a 50mg dose, which is the starting dose for most men with erectile dysfunction. If this dosage isn’t working quickly enough or for long enough, you might want to consider going down the prescription route. On prescription, tablets are available as Sildenafil 25mg, Sildenafil 50mg, or Sildenafil 100mg.

At Oxford Online Pharmacy, we offer both over-the-counter erectile dysfunction treatments and prescription Sildenafil online. After a quick healthcare questionnaire or remote consultation, your Sildenafil tablets are discreetly delivered to your front door.

Citations

1. NHS. About Sildenafil (Viagra) [Internet]. nhs.uk. 2022. Available from:
2. Eardley I, Ellis P, Boolell M, Wulff M. Onset and duration of action of Sildenafil for the treatment of erectile dysfunction. British Journal of Clinical Pharmacology. 2002 Mar 6;53:61S65S.
3. Damle B, Duczynski G, Jeffers BW, Crownover P, Coupe A, LaBadie RR. Pharmacokinetics of a Novel Orodispersible Tablet of Sildenafil in Healthy Subjects. Clinical Therapeutics. 2014 Feb;36(2):236–44.
4. Smith BP, Babos M. Sildenafil [Internet]. PubMed. Treasure Island (FL): StatPearls Publishing; 2023. ‌
5. Zinner N. ORIGINAL RESEARCH—ED PHARMACOTHERAPY: Do Food and Dose Timing Affect the Efficacy of Sildenafil? A Randomized Placebo‐Controlled Study. The Journal of Sexual Medicine. 2007 Jan;4(1):137–44.
6. Coward RM, Carson CC. Tadalafil in the treatment of erectile dysfunction. Therapeutics and Clinical Risk Management [Internet]. 2008 Dec 1;4(6):1315–30. ‌
7. Hartmut Porst, Harin Padma-Nathan, Giuliano F, Anglin G, Varanese L, Rosen RC. Efficacy of tadalafil for the treatment of erectile dysfunction at 24 and 36 hours after dosing: a randomized controlled trial. Urology. 2003 Jul 1;62(1):121–5.
8. Doggrell SA. Comparison of clinical trials with Sildenafil, vardenafil and tadalafil in erectile dysfunction. Expert Opinion on Pharmacotherapy. 2005 Jan;6(1):75–84.
9. Stark S, Sachse R, Liedl T, Hensen J, Rohde G, Wensing G, et al. Vardenafil Increases Penile Rigidity and Tumescence in Men with Erectile Dysfunction after a Single Oral Dose. European Urology. 2001;40(2):181–90.
10. Rajagopalan P, Mazzu A, Xia C, Dawkins R, Sundaresan P. Effect of High-Fat Breakfast and Moderate-Fat Evening Meal on the Pharmacokinetics of Vardenafil, an Oral Phosphodiesterase-5 Inhibitor for the Treatment of Erectile Dysfunction. The Journal of Clinical Pharmacology. 2003 Mar;43(3):260–7.
11. Kedia GT, Uckert S, Assadi-Pour F, Kuczyk MA, Albrecht K. Avanafil for the treatment of erectile dysfunction: initial data and clinical key properties. Therapeutic Advances in Urology [Internet]. 2013 Feb 1;5(1):35–41.
12. Katz EG, Tan RB, Rittenberg D, Hellstrom WJ. Avanafil for erectile dysfunction in elderly and younger adults: differential pharmacology and clinical utility. Therapeutics and Clinical Risk Management [Internet]. 2014 Aug 27;10:701–11. Available from: ‌
13. Medicines and Healthcare Products Regulatory Agency. MHRA Reclassifies Viagra Connect Tablets To A Pharmacy Medicine [Internet]. GOV.UK. 2017.