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Sildenafil Dosage Guide: What’s the Right Dose?

Kelly Brown MD, MBA

Reviewed by Kelly Brown MD, MBA

Written by Erica Garza

Published 01/20/2021

Updated 07/17/2024

Thinking of increasing your sildenafil dosage on your own for even longer, harder erections? Sorry to be a killjoy, but you should never override your healthcare provider’s guidance.

Sildenafil, the active ingredient in Viagra®, is an FDA-approved medication for treating erectile dysfunction (ED). Though it’s a great drug, taking too much or too little can either render it ineffective or set you up for some uncomfortable side effects.

If you’re Googling sildenafil dosages, it might be time for a refresher on how this drug works and how providers determine the correct dose for patients.

While sildenafil has a well-earned reputation for helping guys with ED, it isn’t a cure for erectile dysfunction — and it doesn’t supercharge your libido. What the drug does do is make it easier to get and maintain an erection when you’re already sexually aroused.

But here’s the thing — if you don’t get the dosage right, the medication probably won’t work the way it should.

Sildenafil is available in several dosages. Below, we’ll explain how to find the right sildenafil dosage for ED, what you should know about sildenafil dosage timing, and why you should never exceed the maximum dose of sildenafil in 24 hours.

Like many other medications for ED, sildenafil helps you get and maintain erections by increasing blood flow to the tissue inside your penis.

But sildenafil dosage isn’t based on penis size, SAT scores, your tax bracket, or how badly you want to elevate your sex life.

Here are the most important facts about sildenafil:

  • Sildenafil (the active ingredient in brand-name Viagra) is approved by the FDA for erectile dysfunction and pulmonary arterial hypertension (PAH), a form of high blood pressure in the lungs.

  • Sildenafil is in a class of medications called phosphodiesterase type 5 (PDE5) inhibitors, or PDE5 inhibitors.

  • Sildenafil works by blocking the actions of cGMP-specific phosphodiesterase type 5 — an enzyme that controls blood flow to certain body tissues.

  • PDE5 regulates blood flow to your penis. By blocking its effects, sildenafil improves blood supply to erectile tissue and makes it easier to get — and stay — hard.

  • Sildenafil comes in oral tablet form and is available in a range of dosages, from 20mg up to 100mg (milligrams).

  • It usually takes about a half-hour for sildenafil to start working. Most men who use sildenafil to treat ED take the medication 30 minutes to one hour before sexual activity. It’s recommended to avoid high-fat meals while taking this drug, which can affect its efficacy.

  • Since ED can vary in severity, there’s no one-size-fits-all dose of sildenafil for erectile dysfunction. If you have mild to moderate ED, you may notice major improvements in sexual performance from a relatively low dosage of sildenafil.

  • On the other hand, if you have severe ED or erectile dysfunction caused by a medical condition that limits blood flow to your penis, you might need a higher dosage.

  • While a higher dose of sildenafil may be most effective, taking too much sildenafil can also elevate your risk of side effects, like headache, nausea, or blurred vision.

The sildenafil daily dosage for adults typically starts at 50mg, usually taken roughly one hour before sexual activity — and no more than one dose per day. This can be adjusted to 25mg or 100mg based on the severity of your ED and your response to the medication.

Some versions of sildenafil come in 20mg doses — these film-coated tablets are the generic version of a medication called Revatio®.

This drug was originally developed to treat pulmonary hypertension, but generic Revatio is sometimes used off-label to treat ED. Using multiple 20mg tablets, your prescribed dose of sildenafil for ED could be 40mg, 60mg, or 80mg.

Here’s what you can typically expect from a dosage of sildenafil.

50mg Sildenafil Dosage

Your journey with sildenafil or Viagra will probably begin with a 50mg dose.

Since most men with ED notice improvements in their erections and sexual performance from a 50mg dosage, healthcare providers usually start there and either increase or decrease the dosage accordingly.

In a randomized trial, men’s erections lasted for 19.5 minutes on average after using sildenafil, compared to zero minutes for men who received a non-therapeutic placebo. That’s pretty impressive.

100mg Sildenafil Dosage

The sildenafil max dose is 100mg for ED. Your healthcare provider may prescribe higher doses of sildenafil if you have severe or persistent ED that doesn’t get better with the use of sildenafil at a lower dose.

20 to 25mg Sildenafil

The minimum dosage of sildenafil FDA-approved to treat erectile dysfunction is 25mg. You might be prescribed sildenafil at this dosage if you have mild ED or any health issues that increase your risk of side effects from sildenafil.

As mentioned earlier, some forms of sildenafil come as a 20mg tablet. These are often generic versions of Revatio.

Let’s get something straight, fellas: The dose of sildenafil you use isn’t a measure of manhood — and a higher dosage won’t necessarily produce better effects. There’s no “ideal” dosage of sildenafil for everyone.

That said, 50mg has shown proven benefits for most men in clinical trials.

For example, a series of two studies looked at the effects of 50mg sildenafil in men with erectile dysfunction. After taking this dosage, 71 percent of participants got an erection in 30 minutes or less. After 45 minutes, 82 percent achieved an erection.

You may not want to take 50mg if you experience significant side effects like vision changes, nausea, or painful erections. If you notice side effects from sildenafil at a dosage of 50mg or 100mg, your healthcare provider may suggest going down to 25mg.

If you only have mild ED, you may find that a low dosage is more than enough to improve your symptoms and help you have sex without worrying about getting or maintaining an erection.

But if you have severe or persistent ED, your healthcare provider might prescribe sildenafil at a higher dosage.

It’s that simple. Find the right dosage for you, and take what you need — nothing more, nothing less.

Personalized Rx

Hard results, delivered

For most people, sildenafil is safe and effective, but that doesn’t mean it’s perfect. And like Superman around kryptonite, many negative effects you might experience from sildenafil can be dose-dependent.

Luckily, most potential adverse effects of sildenafil are mild and resolve on their own over time. Still, some may be bothersome.

Common side effects of sildenafil include:

  • Flushing

  • Headache

  • Nasal congestion

  • Dyspepsia (indigestion)

  • Myalgia (muscle pain)

  • Blurred vision

  • Back pain

  • Nausea

  • Dizziness

  • Skin rash

As mentioned briefly above, clinical studies show that the risk of side effects from sildenafil increases with dosage. 

For instance, headaches (the most common side effect of sildenafil) were reported by 16 percent of people at a dosage of 25mg, 21 percent at a dosage of 50mg, and 28 percent at a dosage of 100mg in clinical trials.

Other side effects, such as flushing, indigestion, and nasal congestion, also occurred at a higher rate as the dosage of sildenafil increased.

Sildenafil can also cause more serious side effects like: 

  • Priapism (persistent, painful erections)

  • Hearing loss

  • Sudden loss of vision

  • Death

Seriously, death — so make sure you use this medication as directed, and seek emergency medical help if you experience any of the side effects above.

Priapism — an erection lasting four hours or longer — sounds great until you realize you can permanently damage the tissue in your penis if you don’t do something about it ASAP.

Choose your chew

Like most medications, sildenafil can cause interactions when used with other prescription drugs, alcohol, and certain other substances.

Sildenafil can potentially cause dangerous drug interactions when combined with medications for heart disease or high blood pressure.

  • Nitrates, alpha-blockers, and calcium channel blockers. When sildenafil is used with these or other medications for hypertension or cardiovascular disease, it can contribute to a sudden decrease in blood pressure that may, in some cases, be life-threatening.

  • Recreational drugs. Some party drugs — such as poppers — contain ingredients like nitrites, which can cause potentially dangerous effects when used with PDE5 inhibitors.

  • Things that affect the CYP3A4 enzyme. Sildenafil citrate and other PDE5 inhibitors like Cialis® (tadalafil) and Levitra® (vardenafil) all have negative interactions with medications like itraconazole, ketoconazole, and, oddly enough, grapefruit juice. These things affect the CYP3A4 enzyme and may contribute to higher levels of sildenafil in the bloodstream, potentially increasing the risk of side effects. 

Make sure to tell your healthcare provider if you’re on any of these — a bad mixture could lead to low blood pressure that may actually be fatal. If you take them together by accident, seek medical attention right away.

It’s also important to inform your provider about any underlying health issues or if you’ve previously had heart problems, such as a heart attack, irregular heartbeat, angina (chest pain), or narrowing of your aortic valve.

Also, tell your provider if you have sickle cell anemia, leukemia, a sexually transmitted infection (STI), or — just saying this to be safe — are breastfeeding.

Our guide to sildenafil interactions goes into greater detail about the risks of using this drug with other medications, as well as steps you can take to lower your interaction risk.

Personalized Rx

Enjoy sex like you used to

Erectile dysfunction is a common problem affecting an estimated 30 million adult men in the United States alone.

If you’re one of them, using medication like sildenafil can help you more easily maintain an erection and enjoy a fulfilling, satisfying sex life.

Here’s the bottom line on sildenafil dosages:

  • Sildenafil doesn’t cause sexual stimulation. It’s not just going to give you a four-hour tent pole. If it does, get to a hospital because it might be priapism.

  • No single dose of sildenafil works for everyone. Since erectile dysfunction can vary in severity, your healthcare provider will choose your initial sildenafil dose based on your unique health needs.

  • The most common starting dose is 50mg. Most of the time, your healthcare provider will prescribe sildenafil at a starting dose of 50 mg for use as needed. 

  • You can always adjust your dose. If the initial dosage you’re prescribed isn’t effective or you experience side effects, let your provider know. It’s common and normal to adjust a sildenafil dosage over time to figure out what’ll give you the best results with as few side effects as possible.

  • There’s no over-the-counter sildenafil. Don’t use supplements or other non-prescription pills for the treatment of erectile dysfunction. Prescription drugs for ED are safe and FDA-approved.

Interested in treating ED? Sildenafil is one of several medications for improving blood flow and making it easier to get and maintain an erection when sexually aroused. 

Our guide to erectile dysfunction goes into more detail about what causes ED, as well as what you can do to improve your sexual function. You can also learn more about sildenafil and other ED medications in our guide to the most common erectile dysfunction treatments and drugs.

Let a professional worry about your dosage — you just focus on having the best sex of your life. And don’t forget to stretch! 

7 Sources

  1. Dhaliwal A, et al. A. (2022). PDE5 Inhibitors. https://www.ncbi.nlm.nih.gov/books/NBK549843/
  2. Eardley I, et al. (2002). Onset and duration of action of sildenafil for the treatment of erectile dysfunction. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1874251/
  3. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). (2017). Definition & Facts for Erectile Dysfunction. https://www.niddk.nih.gov/health-information/urologic-diseases/erectile-dysfunction/definition-facts
  4. National Library of Medicine. (2018). Sildenafil. https://medlineplus.gov/druginfo/meds/a699015.html
  5. REVATIO (sildenafil) tablets, for oral use. (2014). https://www.accessdata.fda.gov/drugsatfda_docs/label/2014/021845s011,022473s004,0203109s002lbl.pdf
  6. Smith BP, et al. (2022). Sildenafil. https://www.ncbi.nlm.nih.gov/books/NBK558978/
  7. 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
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.

Kelly Brown MD, MBA
Kelly Brown MD, MBA

Dr. Kelly Brown is a board certified Urologist and fellowship trained in Andrology. She is an accomplished men’s health expert with a robust background in healthcare innovation, clinical medicine, and academic research. Dr. Brown was previously Medical Director of a male fertility startup where she lead strategy and design of their digital health platform, an innovative education and telehealth model for delivering expert male fertility care.

She completed her undergraduate studies at University of North Carolina at Chapel Hill (go Heels!) with a Bachelor of Science in Radiologic Science and a Minor in Chemistry. She took a position at University of California Los Angeles as a radiologic technologist in the department of Interventional Cardiology, further solidifying her passion for medicine. She also pursued the unique opportunity to lead departmental design and operational development at the Ronald Reagan UCLA Medical Center, sparking her passion for the business of healthcare.

Dr. Brown then went on to obtain her doctorate in medicine from the prestigious Northwestern University - Feinberg School of Medicine and Masters in Business Administration from Northwestern University - Kellogg School of Management, with a concentration in Healthcare Management. During her surgical residency in Urology at University of California San Francisco, she utilized her research year to focus on innovations in telemedicine and then served as chief resident with significant contributions to clinical quality improvement. Dr. Brown then completed her Andrology Fellowship at Medical College of Wisconsin, furthering her expertise in male fertility, microsurgery, and sexual function.

Her dedication to caring for patients with compassion, understanding, as well as a unique ability to make guys instantly comfortable discussing anything from sex to sperm makes her a renowned clinician. In addition, her passion for innovation in healthcare combined with her business acumen makes her a formidable leader in the field of men’s health.

Dr. Brown is an avid adventurer; summiting Mount Kilimanjaro in Tanzania (twice!) and hiking the incredible Torres del Paine Trek in Patagonia, Chile. She deeply appreciates new challenges and diverse cultures on her travels. She lives in Denver with her husband, two children, and beloved Bernese Mountain Dog. You can find Dr. Brown on LinkedIn for more information.

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