Exactly How Long Sildenafil Lasts, According to a Urologist

Plus, when to take the pill to avoid a mid-sex softy.

There’s no shame in taking erectile dysfunction medication to give yourself a boost in the bedroom. But no one wants to worry about doing mental math to time your dose of sildenafil, the active ingredient in Viagra and Retavio, before your date to kick in at just the right moment. So, how long does sildenafil last? And how long does it take for sildenafil to work?

All PDE5 inhibitors—a class of erectile dysfunction drugs—last for varying durations, so timing them right is critical to avoid going soft during sex. Medicines like tadalafil last up to 36 hours, while vardenafil and sildenafil wear off after about four. 

This is the exact time you should take your sildenafil before sex to treat erectile dysfunction—according to urologist Amy Pearlman, M.D.—and how long you can expect it to last. 

About the Expert

Amy Pearlman, M.D., is a board-certified urologist who specializes in men’s sexual and hormonal health.

What is Sildenafil?

Erectile dysfunction—a condition where you are unable to achieve or maintain an erection hard enough for sex—affects up to 30 million men in the United States, per estimates from the American Urological Association. ED can be caused by a range of mental and physical factors like diabetes, enlarged prostate, low testosterone, obesity, and depression. 

And erectile dysfunction risk increases by around 10 percent per decade, according to James Staheli, D.O. This means the older you get, the more likely you are to experience ED. 

Luckily, research shows that medications like sildenafil and tadalafil are highly effective in treating erectile dysfunction that stems from a physical cause (1). Nearly 3 million men in the United States are prescribed sildenafil—a PDE5 inhibitor medication—to treat erectile dysfunction and improve their sex lives. For good reason: Sildenafil is reported to be around 70 percent effective at treating erectile dysfunction in men (2). 

PDE5 inhibitors block the PDE5 enzyme, which controls blood flow in the corpus cavernosum (the erectile tissue in the shaft of the penis). Blood vessels in the penis are able to relax when the PDE5 enzyme is blocked, boosting blood flow and circulation. This helps you get a harder, and more reliable, erection. 

Sildenafil is also frequently prescribed to men who experience premature ejaculation—aka shooting too early (3). Sildenafil effectively delayed ejaculation from vibratory stimulation in a clinical trial, increasing the average from 2.23 minutes to 3.89 minutes (4). 

Beyond helping in the bedroom, Sildenafil can help treat pulmonary hypertension—a condition which occurs when there is abnormally high blood pressure in the blood vessels between your heart and lungs.

The drug  may also have longevity-boosting cardioprotective benefits, according to a 2023 study in the Journal of Sexual Medicine (5). Men who took PDE5s, like sildenafil, over a 14-year period were 39 percent less likely to die from cardiovascular causes than men who didn’t take the drug. Their all-cause mortality risk was 25 percent lower, and their risk for major adverse cardiovascular events (such as heart attack and stroke) was down 13 percent.  

Healthy Aging

How Long Does Sildenafil Last?

You can expect your sildenafil dose to last for about four to six hours after you take it, according to Pearlman. Although, this depends heavily on your individual metabolism and dose (6)—which is why it’s risky to take it more than four hours before you intend to have sex. 

If your doctor prescribes sildenafil, you’ll most likely be given a 50 mg pill that you can swallow about an hour before you plan to get frisky (6). If 50mg isn’t cutting it—or you’re experiencing side effects like dizziness, fainting, or heart palpitations—your doctor may adjust your dose.

Generally, sildenafil hangs out in your system for about 24 hours, but you probably won’t be able to get an on-demand erection for a full day.  A few lucky men experience some effect for up to 18 hours (6), but for many men the medication wears off after about three or four hours (7). 

Will I stay erect after I ejaculate?

Sildenafil probably won’t keep you rock hard after ejaculation but the medication may shorten your refractory period (8), so you may be ready for round two faster than when you don’t take the med. A 2003 study found that sildenafil caused a significant reduction of the postejaculatory refractory time (9).

A word of warning: If your erection lasts for more than four hours after taking a dose of sildenafil, seek medical attention, pronto.  A ​​priapism, or prolonged, persistent erection, puts you at risk for permanent damage to your penis (10). 

Boost Your Sex Life

Can You Make Sildenafil Last Longer?

Unfortunately, there’s no magic protocol to make your dose of sildenafil last longer, per Pearlman. 

But research shows that certain lifestyle choices could impact the effectiveness of the drug. Here’s what to avoid:

High-fat diets

A 2019 study found that eating a high fat meal delayed the peak benefits of sildenafil’s effects by around 60 minutes (11). This is because food slows the absorption of sildenafil.

No matter what you eat, taking sildenafil right after eating might not produce the best results. “If taken right after eating a meal, sildenafil may take longer to take effect,” Pearlman explains. “It’s best taken on an empty stomach.” 


It’s okay to have a couple drinks while taking sildenafil, but going overboard can damper the drug’s effects  and make it harder to get an erection (12). You may also be more prone to common side effects of sildenafil, like lightheadedness, heart palpitations, or fainting if you drink in tandem with your dose.


Smoking damages your blood vessels (13), making it more likely for plaque to form in your arteries, which can decrease your blood flow, making it harder for you to get an erection. Although there is no direct risk associated with smoking while taking sildenafil, it could reduce the effectiveness of the drug (14). 

How Long Does it Take for Sildenafil to Work? 

You can expect your sildenafil to kick in anywhere from 30 minutes to two hours after your dose, but most doctors recommend timing it as close to an hour before sex as you can. This is because maximum drug concentration—when the medication has reached its peak levels in your bloodstream—averages around one hour (15). 

You’ll typically want to take your sildenafil one hour before having sex, Pearlman says. “Although you can take it as early as 30 minutes [before sex] or as long as about 4 hours prior to desired erection.”

But if you take it too early before sex, it’s “definitely possible” for sildenafil to wear off and ruin the moment, Pearlman warns. 

How Can I Get Sildenafil?

If you have trouble getting or keeping an erection, there’s no shame in asking if sildenafil might help. 

It’s important to get ED medication through a licensed physician, as scammy nonprescription or herbal/natural ED meds can be straight-up dangerous. And don’t make changes to your dosage without talking to a doc. 

Sildenafil is available through Hone. To see if you qualify for treatment, order your at-home hormone assessment today.

If your erectile dysfunction isn’t improving on sildenafil, or if you feel the dose isn’t lasting as long as it should, Pearlman suggests talking to your doctor about tadalafil (Cialis)—a daily PDE5 inhibitor that remains in the bloodstream longer than sildenafil.

“Some men respond better to other oral PDE5 inhibitors and don’t respond to others,” Pearlman says. “Additional therapies—either in addition to sildenafil or instead of sildenafil—include vacuum erection device, penile constriction band, focused shockwave therapy, intraurethral medication, intracavernosal injection therapy, penile implant surgery.”

  1. 1. Olsson, et al (2000) Sildenafil citrate (Viagra) is effective and well tolerated for treating erectile dysfunction of psychogenic or mixed aetiology
  2. 2. Hatzimouratidis, et al (2006) Sildenafil in the treatment of erectile dysfunction: an overview of the clinical evidence.
  3. 3. Raveendran, et al (2021) Premature ejaculation – current concepts in the management: A narrative review
  4. 4. Ekmekcioglu, et al (2005) Effects of sildenafil citrate on ejaculation latency, detumescence time, and refractory period: placebo-controlled, double-blind, crossover laboratory setting study
  5. 5. Kloner, et al (2023) Effect of phosphodiesterase type 5 inhibitors on major adverse cardiovascular events and overall mortality in a large nationwide cohort of men with erectile dysfunction and cardiovascular risk factors
  6. 6. Smith, et al (2023) Sildenafil
  7. 7. Alwhaibi, et al (2021) Pharmacokinetic profile of sildenafil citrate in healthy Middle Eastern Males: Comparison with other ethnicities
  8. 9. Mondaini, et al (2003) Sildenafil does not improve sexual function in men without erectile dysfunction but does reduce the postorgasmic refractory time
  9. 10. Silberman, et al (2023) Priapism
  10. 11. Costantini, et al (2019) The first-generation phosphodiesterase 5 inhibitors and their pharmacokinetic issue
  11. 12. Sivaratnam, et al (2020) Behavior-Related Erectile Dysfunction: A Systematic Review and Meta-Analysis
  12. 14. Murtadha, et al (2021) Changes in the Pharmacokinetics and Pharmacodynamics of Sildenafil in Cigarette and Cannabis Smokers
  13. 15. Nichols, et al (2002) Pharmacokinetics of sildenafil after single oral doses in healthy male subjects: absolute bioavailability, food effects and dose proportionality