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What Does Viagra Do to Men?

Martin Miner

Reviewed by Martin Miner, MD

Written by Erica Garza

Published 04/27/2018

Updated 01/24/2025

You’ve probably heard some impressive claims about Viagra® — it’s a bedroom ”game-changer,” it’s a miracle drug, etc.

Viagra’s name is widely known. It’s the most popular medication for erectile dysfunction (ED) in the world today, and for good reason — for most men, it works.

But what does Viagra do to your sexual experiences? Does Viagra make you hornier? Harder? Bigger? What can you expect sex to look and feel like after taking it?

These are all good questions, and we’ll answer them in detail below. Keep reading to find out what happens when you take Viagra, what it does to men, and how you know it’s working.

Want the lowdown on Viagra? A few things to know off the bat:

  • Viagra and its main ingredient, sildenafil, are medications known as PDE5 (phosphodiesterase type 5) inhibitors.

  • These drugs increase blood flow to the penis to help you get an erection with sexual stimulation.

  • People who take Viagra are likely to experience some side effects, like headaches, dizziness, or nausea.

  • Fortunately, these side effects are mild in most cases and eventually go away.

Take it from Him

"In a short amount of time, I've noticed a significant difference. Any awkwardness around not being able to maintain an erection has disappeared completely.

I was a bit worried it would be a situation where I would have an erection for hours on end, but it hasn't been that. When I want it, it's easy to achieve, which is perfect for me and for my partner."

- Alex, 29

Incentivized Review

Viagra has one of the biggest glow-up stories in the world of medicine. Originally designed as a blood pressure medication for people trying to avoid chest pain (angina) and stiff left arms, it quickly became clear that the pill’s most curious side effect was harder erections.

When researchers realized it could be prescribed to help men with ED function more normally, they knew they had a hit on their hands.

Since it came to market in the late ‘90s, Viagra has grown from a niche medicine into a medication used by millions of men around the world to treat erectile dysfunction.

Viagra’s active ingredient, sildenafil, is still prescribed for pulmonary arterial hypertension (under the name Revatio®). But today, the drug is mostly — and most popularly — known for its penile powers.

What’s in Viagra?

Viagra’s main ingredient, sildenafil, is part of a class of drugs referred to as phosphodiesterase type 5 inhibitors (PDE5 inhibitors). Unlike non-prescription supplements, this prescription medication is approved by the FDA (U.S. Food and Drug Administration) for the treatment of erectile dysfunction.

Viagra comes in tablet form. The medication is designed to be taken about 30 minutes to an hour before sexual activity to help you get or maintain an erection during sex.

Viagra treats ED by increasing blood flow to the penis, making it easier to get or maintain an erection.

Its active ingredient, sildenafil, inhibits an enzyme called PDE5, which helps control blood flow to your penis. By tamping down this enzyme, sildenafil relaxes blood vessels to promote better blood flow.

PDE5 normally breaks down cGMP (cyclic guanosine monophosphate), which is responsible for relaxing the smooth muscles in the penis. By preventing PDE5 from working correctly, cGMP stays elevated, and Viagra essentially gives blood the green light to flow into the erectile tissues inside your penis when you feel sexually stimulated.

This mechanism of action is similar to how other oral ED medications work (like Cialis®, Stendra®, and Levitra®).

Does Viagra Give You an Erection If You Have ED?

If you have erectile dysfunction, Viagra can be extremely beneficial to your sexual function and experience — as well as the level of enjoyment you get from sex. Even a relatively modest dose of Viagra can make it significantly easier to get hard and stay hard during intercourse.

In clinical trials of Viagra, more than 82 percent of men with erectile dysfunction reported an improvement in their erections after using Viagra at a dosage of 100mg (milligrams). This is the highest dosage prescribed for ED.

Even at the lowest prescribed dosage of 25mg, Viagra produced improvements in erections for 63 percent of men with erectile dysfunction.

Does Viagra Make You Horny?

A common myth about Viagra is that it can increase your sex drive and make you feel more motivated to have sex.

Viagra is designed to improve physical performance during sex — that is, your ability to get and maintain an erection. However, it’s not associated with any significant increase in sexual interest, sexual arousal, or sex drive (libido) in general.

For the most part, the male sex drive is controlled by hormonal factors, including the androgen (male hormone) testosterone. For example, a common sign of low testosterone is a weaker-than-normal sex drive.

Viagra isn’t a hormonal medication. As such, it won’t have any significant effects on your levels of androgen hormones or sex drive. Instead, Viagra simply makes it easier to get and maintain an erection when you’re already in the mood for sex.

Does Viagra Make You Last Longer?

This question is tough to answer with a simple yes or no since it depends on various factors. Viagra could potentially improve your sexual performance overall.

Some studies suggest Viagra can be a potential treatment option for premature ejaculation (PE), so it is sometimes prescribed off-label for that purpose. (Off-label use means a medication is prescribed by a healthcare provider to treat something it’s not FDA-approved for).

In a 2007 study, researchers noted that Viagra is ”effective and safe” for treating PE. They added that it had a higher efficacy than the SSRI (selective serotonin reuptake inhibitor) paroxetine and the ”squeeze technique.”

A study from 2005 found that while Viagra didn’t significantly impact intravaginal ejaculatory latency (the amount of time until ejaculation), it did improve men’s confidence, sexual satisfaction, and perception of ejaculatory control.

Does Viagra Reduce the Refractory Period?

Another common belief about Viagra is that it can reduce the refractory period — the amount of time that needs to pass after a man reaches orgasm before he can get hard again.

In this case, the common belief about Viagra is true. Viagra lasts around four hours in your system, so you may feel its effects working even after you’ve ejaculated. Some scientific studies show that ED medications like Viagra reduce the amount of time needed to recover after sex, often by quite a significant amount.

For instance, a small study of 20 people looked into Viagra’s effect on refractory time. It found that a standard 100mg dose of sildenafil citrate reduced the average male post-sex recovery time to about 2.6 minutes (versus roughly 10.8 minutes in the placebo group).

However, it’s worth noting that not every study produces these results. So Viagra’s potential effects on refractory time may not be the same for all men who take it.

Does Viagra Make Your Penis Bigger?

Sorry, there are no before-and-after size differences in males who take Viagra. The medication doesn’t make your penis bigger, though it may appear that way due to extra firmness.

Viagra also doesn’t increase ejaculation volume. If that’s your reason for wanting to take the medication, you’re better off staying hydrated and not masturbating too often.

What Happens When You Take Viagra?

Does Viagra make you harder? Yes — here’s why.

Erections require a combination of stimulation and blood flow. When you feel sexually aroused — whether due to visual stimulation, physical stimulation, or both — impulses from your nervous system cause increased blood flow to your penis.

Both brand-name Viagra and generic sildenafil work by increasing blood flow to the penis. The corpora cavernosa — a pair of sponge-like areas of tissue inside your penis — fill with blood, which causes your penis to expand and harden.

To keep your penis firm during sex, pressure builds up within a fibrous membrane called the tunica albuginea. This blocks outflow of blood and traps blood inside your penis until you either no longer feel stimulated or reach orgasm and ejaculate.

Potential Cardioprotective Effects of Viagra

Research from 2024 suggests potential cardioprotective effects of sildenafil and tadalafil (generic Cialis, another PDE5 inhibitor). This means Viagra might help minimize the risk of cardiovascular disease and related events, like heart attack and stroke.

How so? Sildenafil may safeguard the heart and blood vessels by lowering blood pressure, inflammation, and oxidative stress. More research is still needed, though.

ED treatment personalized

Viagra generally takes 30 minutes to an hour to start working and should be taken on an empty stomach. It might take a little longer to kick in if you eat a large, high-fat meal before or shortly after using this medication.

When Viagra starts working, you won’t suddenly develop an erection or notice any rapid change in your sex drive or sexual arousal. Also, it’s not a psychoactive medication, meaning it won’t have any noticeable effect on the way you feel, think, or perceive things during sex.

Instead, you’ll find it easier to get and maintain an erection after taking the medication. This might mean you’re able to get hard when you usually wouldn’t or that your Viagra-supported erections are firmer than usual.

The effects of Viagra are purely physical, so it won’t directly change your emotions. That said, if you have erectile dysfunction, Viagra’s effects on your sexual performance can give you a confidence boost or make sex more enjoyable.

In some cases, using Viagra might not make your erection develop faster or become firmer than usual. Still, it might make it easier to maintain an erection during sex.

Wondering if your man is taking a prescription drug to keep up his energy in bed? Consider asking him. He may be embarrassed to need the medication (which might be why he hasn’t already told you). But if you let him know it’s nothing to be embarrassed about, you might get your answer while bringing you two closer together.

Some subtle signs he’s taking Viagra may include fewer partial erections and increased satisfaction with your sex life. But there’s really no obvious tell.

If your partner’s erections are suddenly more full and frequent, it’s not necessarily a sign of medication — he could just be improving his health (mentally or physically).

Before you start thinking Viagra’s some kind of perfect pill, let’s talk side effects. Common side effects of Viagra include:

  • Nausea or dyspepsia (indigestion)

  • Myalgia (muscle pain) or back pain

  • Abnormal vision (blurred vision and/or changes in color vision)

  • Dizziness

  • Rash or facial flushing

  • Headaches

  • Nasal congestion

In rare cases, Viagra can cause more severe side effects, including:

  • Priapism (a prolonged, painful erection)

  • Sudden loss of vision from damage to the optic nerve

  • Loss of hearing

If you notice any of these serious side effects after taking Viagra, seek medical attention right away. A prolonged erection is considered an emergency and should be treated immediately.

Viagra is a safe and effective medication for most men. But always talk to your healthcare provider before using it, especially if you have a personal history of medical conditions such as:

As noted, recent research has suggested potential cardioprotective effects of Viagra and similar drugs, meaning the medication might help reduce the risk of cardiac events like stroke or heart failure.

Viagra Drug Interactions

Like other medications, Viagra can cause drug interactions, specifically with alpha-blockers or nitrates like nitroglycerin. Viagra can also interact with nitrates found in recreational drugs such as ”poppers” and cause dangerously low blood pressure.

Telling your healthcare provider about any prescription and over-the-counter medications you currently use (or have recently used) can prevent this. You should also let them know if you’ve had allergic reactions to ED medication in the past.

What does Viagra do to men? What it’s supposed to. Unfortunately, this isn’t something that’s always well understood. Here are some takeaways:

  • Viagra may help improve erectile function in men with ED. Studies show the medication has a high success rate in making it easier for men to get and maintain erections.

  • Viagra doesn’t make you horny or trigger sudden erections. Viagra doesn’t have any noticeable impact on sex drive or general level of interest in sex. It also won’t trigger a sudden erection or prevent you from having sex normally.

  • Viagra does have side effects, but most are mild and temporary. Still, always tell your provider if you notice something unusual or if you have pre-existing medical conditions.

  • Follow your medical provider’s guidance when taking Viagra. Like Cialis (tadalafil), Levitra (vardenafil), Stendra (avanafil), and other PDE5 inhibitors, Viagra should be prescribed and taken only under the medical advice of a healthcare professional.

Put simply, Viagra makes getting and maintaining an erection easier. That’s it — there’s no catch or hidden effects, provided you use it as prescribed.

If you’re ready to see what Viagra can do for your sexual experience or are curious about taking sildenafil as a chewable hard mint, start by taking our free online ED questionnaire.

7 Sources

  1. Aversa A, et al. (2000). Effects of sildenafil (Viagra) administration on seminal parameters and post-ejaculatory refractory time in normal males. https://pubmed.ncbi.nlm.nih.gov/10611201/
  2. Ekmekçioğlu O, et al. (2005). Effects of sildenafil citrate on ejaculation latency, detumescence time, and refractory period: placebo-controlled, double-blind, crossover laboratory setting study. https://pubmed.ncbi.nlm.nih.gov/15708051/
  3. Köhler TS, et al. (2024). The Princeton IV consensus recommendations for the management of erectile dysfunction and cardiovascular disease. https://pubmed.ncbi.nlm.nih.gov/39115509/
  4. McMahon C, et al. (2005). Efficacy of sildenafil citrate (Viagra) in men with premature ejaculation. https://pubmed.ncbi.nlm.nih.gov/16422868/
  5. Smith B, et al. (2022). Sildenafil. https://www.ncbi.nlm.nih.gov/books/NBK558978/
  6. VIAGRA- sildenafil citrate tablet, film coated. (2017). https://www.accessdata.fda.gov/spl/data/40578e70-350a-4940-9630-55d90989c146/40578e70-350a-4940-9630-55d90989c146.xml
  7. Wang W, et al. (2007). Can sildenafil treat primary premature ejaculation? A prospective clinical study. https://pubmed.ncbi.nlm.nih.gov/17470165/
Editorial Standards

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references. See a mistake? Let us know at [email protected]!

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.

Martin Miner, MD

Dr. Martin Miner is the founder and former co-director of the Men’s Health Center at the Miriam Hospital in Providence, Rhode Island. He served as Chief of Family and Community Medicine for the Miriam Hospital, a teaching hospital of the Warren Alpert Medical School, from 2008 to 2018. The Men’s Health Center, under his leadership, was the first such center to open in the US. He is a clinical professor of family medicine and urology at the Warren Alpert Medical School of Brown University in Providence and has been charged with the development of a multidisciplinary Men’s Health Center within the Lifespan/Brown University system since 2008.

Dr. Miner graduated Phi Beta Kappa from Oberlin College with his AB in biology, and he received his MD from the University of Cincinnati College of Medicine. Upon receiving his MD, he completed his residency at Brown University. He practiced family medicine for 23 years, both at Harvard Pilgrim Health Care and in private practice.

Dr. Miner presently holds memberships in the American Academy of Family Physicians, the Rhode Island and Massachusetts Academy of Family Physicians, and the American Urological Association, and he is a fellow of the Sexual Medicine Society of North America. He is the former president of the American Society for Men’s Health and the current historian. He is the vice president of the Androgen Society, developed for the education of providers on the truths of testosterone therapy. Dr. Miner has served on the AUA Guideline Committees for erectile dysfunction, Peyronie’s disease, testosterone deficiency, and early screening for prostate cancer. He has served on the testosterone committees of the International Consultation on Sexual Medicine. He has presented both at the NIH and the White House on men’s health initiatives and has authored over 150 peer-reviewed publications and spoken nationally and internationally in multiple venues. He has co-chaired the Princeton III and is a steering committee member and one of the lead authors of Princeton IV, constructing guidelines for the evaluation of erectile dysfunction, the use of PDE5 inhibitors, and cardiac health and prevention.

Dr. Miner was chosen as the Brown Teacher of the Year in 2003 and 2007 and was recognized by the Massachusetts Medical Society’s Award as achieving the most significant contribution to Men’s Health: 2012.

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