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Sildenafil Dosage Guide: What is the Right Dose?

Mike Bohl, MD, MPH, ALM

Reviewed by Mike Bohl, MD, MPH, ALM

Written by Geoffrey Whittaker

Published 01/20/2021

Updated 01/10/2024

Here’s everything you need to know about sildenafil dosages.

Sildenafil, the active ingredient in Viagra®, is an FDA-approved medication for treating erectile dysfunction (ED). If you’re Googling dosages, you may have some misunderstandings about what it’ll do for you — and that’s okay. 

Sildenafil has a reputation — a well-earned one — for helping people with ED. But it doesn’t do this by making you pitch tents like entry day at a music festival.

Sildenafil doesn’t cure erectile dysfunction at all, actually. There’s no “cure” for erectile dysfunction. What it does is help make it easier for you to get and maintain an erection when you’re already sexually aroused.

And importantly, your dosage will impact how effective it is at doing this. 

Sildenafil is available in several dosages. Finding and using the right one for your needs will help you get the best results while limiting your risk of side effects.

Below, we’ll explain and share the most common dosages for this medication. 

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Sildenafil Dosage: The Basics

Like many other medications for ED, sildenafil helps primarily by increasing blood flow to the tissue inside your penis. Dosage isn’t based on penis size, SAT scores or your tax bracket — all that is false.

Here are the most important facts about sildenafil:

  • Sildenafil (the active ingredient in 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 part of a class of medications referred to as phosphodiesterase type 5 (PDE5) inhibitors, or PDE5 inhibitors

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

  • PDE5 is responsible for regulating blood flow to your penis. By blocking the effects of PDE5, sildenafil improves the supply of blood to the blood vessels and 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 around 30 minutes for sildenafil to start working. Most men who use sildenafil to treat ED take the medication 30 minutes to one hour before sexual activity.

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

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

  • While a higher dosage of sildenafil may be most effective, taking too much sildenafil can also increase your risk of experiencing side effects.

Common Sildenafil Dosages 

Sildenafil is available in several dosages. The standard dosage for ED is 50mg, usually taken about one hour before sexual activity. 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 tablets — these tablets are the generic version of a medication called Retatio. This medication was originally developed to treat pulmonary arterial 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

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

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 grade 3 or 4 erections lasted for 19.5 minutes (median) after using sildenafil, compared to zero minutes (median) for men who received a non-therapeutic placebo. We’ll gladly take 20 points over… Zero.

100mg Sildenafil

100mg is the maximum recommended dosage of sildenafil for ED. Your healthcare provider may prescribe sildenafil at this dosage 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

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

Some forms of sildenafil come as a 20mg tablet. These are often generic forms of Revatio® — a version of sildenafil primarily used to treat PAH.

Factors that Affect Sildenafil Dosage

Let’s get something straight, fellas: the dose of sildenafil you use is not a measure of manhood. 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 sildenafil at this dosage, 71 percent of the men developed an erection in 30 minutes or less. After 45 minutes, 82 percent achieved an erection.

But dosages are dependent on your unique needs — not averages.

You may not want to take 50mg if you experience significant side effects. If you notice side effects from sildenafil at a dosage of 50mg or 100mg, your healthcare provider may suggest reducing your dosage 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 your erection.

On the other hand, if you have severe or persistent ED, your healthcare provider may prescribe sildenafil at a higher dosage.

It’s that simple, and it’s important to view the situation from that viewpoint. Find the right dosage for you, and take what you need — nothing more, nothing less. We all need a little help sometimes, right?

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Sildenafil Dosage and Side Effects

For most people, sildenafil is a safe and effective medication, but that doesn’t mean it’s perfect. And like Superman around kryptonite, many of the 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, although some may be bothersome.

Common side effects of sildenafil include:

  • Flushing

  • Headache

  • Nasal congestion

  • Dyspepsia (indigestion)

  • Myalgia (muscle pain)

  • Abnormal vision

  • Back pain

  • Nausea

  • Dizziness

  • Skin rash

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

For example, 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 also causes some 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 make sure you seek emergency medical help immediately 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. 

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Sildenafil Dosage and Medication Interactions

Like other medications, sildenafil can cause interactions when used with drugs, alcohol or other substances.

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

  • Nitrates, alpha-blockers, calcium channel blockers. When sildenafil is used with these or other medications used to treat hypertension and/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 — containing ingredients such as nitrites, which can also cause potentially dangerous effects when used with PDE5 inhibitors such as sildenafil.

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

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

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

Also, tell them if you have or have had sickle cell anemia, leukemia, sexually transmitted infection or — just saying this to be safe — are breastfeeding.

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

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Finding the Right Dose of Sildenafil You

Erectile dysfunction is a common problem affecting an estimated 30 million adult men in the United States alone. If you’re one of these men, using medication like sildenafil can help you more easily maintain an erection and enjoy a fulfilling, satisfying sex life

  • 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.

  • Since erectile dysfunction can vary in severity, no single dose of sildenafil works for everyone. Instead, your healthcare provider will choose your initial sildenafil dose based on the severity of your ED, your general health and other factors. 

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

  • If the initial dosage you’re prescribed isn’t effective or if you experience side effects, make sure to talk to your healthcare provider. It’s common and normal to adjust your sildenafil dosage over time to provide the best results with as few side effects as possible. 

  • Don’t use supplements or other non-prescription pills for the treatment of erectile dysfunction. Prescription drugs 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 you’re 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! 

8 Sources

  1. Sildenafil. (2018, January 15). Retrieved from https://medlineplus.gov/druginfo/meds/a699015.html
  2. Smith, B.P. & Babos, M. (2022, May 3). Sildenafil. StatPearls. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK558978/
  3. Dhaliwal, A. & Gupta, M. (2022, April 19). PDE5 Inhibitors. StatPearls. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK549843/
  4. Erection Ejaculation: How It Occurs. (2020, November 27). Retrieved from https://my.clevelandclinic.org/health/articles/10036-erection-ejaculation-how-it-occurs
  5. REVATIO (sildenafil) tablets, for oral use. (2014, March). Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/label/2014/021845s011,022473s004,0203109s002lbl.pdf
  6. Eardley, I., Ellis, P., Boolell, M. & Wulff, M. (2002, February). Onset and duration of action of sildenafil for the treatment of erectile dysfunction. British Journal of Clinical Pharmacology. 53 (Suppl 1), 61S-65S. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1874251/
  7. VIAGRA- sildenafil citrate tablet, film coated. (2017, December). Retrieved from https://www.accessdata.fda.gov/spl/data/40578e70-350a-4940-9630-55d90989c146/40578e70-350a-4940-9630-55d90989c146.xml
  8. Definition & Facts for Erectile Dysfunction. (2017, July). Retrieved from https://www.niddk.nih.gov/health-information/urologic-diseases/erectile-dysfunction/definition-facts
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.

Mike Bohl, MD, MPH, ALM

Dr. Mike Bohl is a licensed physician and the Director of Scientific & Medical Content at a stealth biotech startup. Prior to joining Hims & Hers, Dr. Bohl spent several years in digital health focusing on patient education. He has also worked in medical journalism for The Dr. Oz Show and Sharecare and has served on the Medical Expert Board of Eat This, Not That!.

Dr. Bohl obtained his Bachelor of Arts and Doctor of Medicine from Brown University, his Master of Public Health from Columbia University, and his Master of Liberal Arts in Extension Studies—Journalism from Harvard University. He is currently pursuing a Master of Business Administration and Master of Science in Healthcare Leadership at Cornell University. Dr. Bohl trained in internal medicine with a focus on community health at NYU Langone Health.

Dr. Bohl is Certified in Public Health by the National Board of Public Health Examiners, Medical Writer Certified by the American Medical Writers Association, a certified Editor in the Life Sciences by the Board of Editors in the Life Sciences, a Certified Personal Trainer and Certified Nutrition Coach by the National Academy of Sports Medicine, and a Board Certified Medical Affairs Specialist by the Accreditation Council for Medical Affairs.

In addition to his written work, Dr. Bohl has experience creating medical segments for radio and producing patient education videos. You can find Dr. Bohl on LinkedIn for more information

Dr. Bohl lives in Manhattan and enjoys biking, resistance training, sailing, scuba diving, skiing, tennis, and traveling. You can find Dr. Bohl on LinkedIn for more information.

Education

  • Bachelor of Arts, Egyptian and Ancient Western Asian Archaeology. Brown University |

  • Doctor of Medicine. |

  • Master of Public Health, General Public Health. |

  • Master of Liberal Arts, Journalism. |

  • Master of Business Administration. | (anticipated 2024)

  • Master of Science, Healthcare Leadership. | (anticipated 2024)

Training

  • NYU Internal Medicine Residency—Brooklyn Community Health Track. |

Certifications

  • Certified in Public Health.

  • Medical Writer Certified.

  • Editor in the Life Sciences.

  • Certified Personal Trainer.

  • Certified Nutrition Coach.

  • Board Certified Medical Affairs Specialist. Accreditation Council for Medical Affairs

  • Digital Storytelling Graduate Certificate.

  • Marketing Management and Digital Strategy Graduate Certificate.

Publications

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