Viagra^® Dosage Guide: What is the Right Viagra Dose for You?

Although Viagra^® is effective for most guys with erectile dysfunction (ED), it’s important to make sure you’re taking the right dose. Too low of a Viagra dosage and your erections may not be as firm or reliable as they could be. Meanwhile, taking too high a dosage of Viagra can increase your risk of side effects.

So, how much Viagra should you take the first time? That’s a question your healthcare provider should be able to answer since it varies from person to person. For most men, your first dose will be 50 mg, taken as needed up to once a day. However, older people or those who have kidney or liver issues might start at a lower dose

Although your healthcare provider will provide the ultimate answer, we can address some general questions about this FDA-approved medication like how it works, typical dosages, and factors that influence optimal dosage.

Viagra is a medication for treating erectile dysfunction famously called “the little blue pill.” The active ingredient in Viagra is called sildenafil citrate. It’s available as a brand-name drug under the name Viagra and as a generic medication called sildenafil, which is usually available at a much lower cost per tablet.

Viagra is part of a class of drugs called phosphodiesterase type 5 or PDE5 inhibitors. In essence, they work by relaxing the blood vessels in your penis to improve blood flow.

Erections are all about healthy blood flow. When you’re aroused, your nervous system sends signals to relax the blood vessels that supply the penis. This causes the ​​corpora cavernosa (the erectile tissues inside your penis) to expand as blood flows in. By keeping the blood vessels dilated, Viagra makes this process easier.

Viagra comes as an oral tablet and is available in three doses:

• 25mg. This is the lowest dose of Viagra. It’s usually prescribed to men with mild erectile dysfunction who only need a little bit of help getting and staying hard or to men who are experiencing bothersome side effects at higher doses.

• 50mg. This is the usual starting dose of Viagra for most men. Your healthcare provider may start you on this dose if you have ED and want to try medication.

• 100mg. This is the maximum dose of Viagra. It’s usually prescribed to men with severe ED or men who don’t notice improvements at 50mg.

Sildenafil, the active ingredient in Viagra, is available in the same doses. 

Additionally, sildenafil is available in a 20mg dose as either brand-name Revatio^® or its generic. Revatio is a medication used to treat pulmonary arterial hypertension (PAH). By taking multiple tablets of Revatio or its generic form for ED, it’s possible to approximate the doses of Viagra. But you should only do this if it’s what a healthcare provider prescribes.

Finding the perfect Viagra dose can be a matter of trial and error. Your healthcare provider might adjust your Viagra dosage by weight, age, or other factors. 

It’s necessary to consider all of these factors holistically. For example, the optimal Viagra dosage for 70-year-old men with no underlying health problems could be lower than the optimal Viagra dosage for 50-year-old men with health conditions like diabetes. Determining proper dosage depends on all these factors collectively. 

Additionally, erectile dysfunction can vary in severity, which can also influence the Viagra dosage prescribed.

Viagra 25mg Dose: Lowest Dose Viagra

Currently, 25mg is the lowest dose of Viagra approved by the FDA to treat ED. It’s less likely to cause side effects than higher doses, all while providing relief from mild erectile dysfunction. 

If you have mild ED or if you experience side effects of Viagra at a higher dose, your healthcare provider may suggest 25mg of Viagra. 

Other reasons your doctor may start you at 25mg are if you:

• Have liver or kidney dysfunction

• Are over the age of 65

• Are taking certain medications, such as alpha-blockers for hypertension,  antiretroviral medications used to treat HIV, and medications that inhibit the enzyme CYP3A4

In clinical trials that led to the approval of Viagra, 63 percent of men who were treated with this 25 mg dose of Viagra reported improved erections.

The most common side effects in phase II/III clinical trials at this dose were:

Viagra 50mg: A Typical Starting Dose of Viagra

Doctors often start by prescribing a dose of 50mg of Viagra for treating erectile dysfunction.

Most men who use Viagra for erectile dysfunction report feeling improvements with this dose. In clinical trials of Viagra, 74 percent of men with ED reported improvements in their erections after using this dose, compared to only 24% who took a placebo.

The most common side effects in phase II/III clinical trials were:

Less common side effects included:

Viagra 100mg: The Maximum Viagra Dose

The max dose of Viagra approved by the FDA (U.S. Food and Drug Administration) is 100mg. Your healthcare provider might prescribe Viagra at this dose if you have severe erectile dysfunction or if you don’t feel fully able to get and/or maintain an erection after taking 50mg of Viagra.

Does a higher dose of Viagra work better?

Research does suggest that taking Viagra at a prescribed dose of 100mg is more likely to treat ED than other doses. In clinical trials, 82 percent of men who used a 100mg dose reported improvements in their erections.

However, people who take Viagra at a dose of 100mg are also more likely to experience side effects than those who take lower doses.

In particular, taking Viagra at this dose increases the risk of certain vision-related side effects, such as blurred vision, altered color vision, and increased sensitivity to light. It also seems to raise the prevalence of common side effects with clinical trials reporting the following in at least 4% of people:

You should never exceed a 100mg dose of Viagra. It’s also important not to take Viagra more than once a day, and unless your healthcare provider specifically instructs you to, you should not take more than one dose of Viagra within a 24-hour period.

Make sure to alert your healthcare provider if you still find it difficult to get or maintain an erection after using 100mg of Viagra.

Following the medical advice of a healthcare professional is the best way to find a Viagra dosage to improve your erections and prevent sexual dysfunction with minimal side effects.

If you have ED, your healthcare provider will determine a recommended dosage of Viagra after taking several factors into account, including:

• Whether you failed to respond to previous dosages

• The side effects you’re experiencing

• The severity of your erectile dysfunction

• Your age, medical history, and overall health

• Any medications you’re currently prescribed

It may take a few months to “dial in” your dosage of Viagra. If you’re prescribed Viagra and don’t think it’s working as effectively as it should, be sure to let your healthcare provider know. This may result in dosage adjustments.

If Viagra isn’t the right choice for you, your healthcare provider might recommend changing to a different ED treatment. Common alternatives to Viagra include:

• Cialis^®, a longer-lasting ED medication that contains the active ingredient tadalafil

• Levitra^® and Staxyn^®, which contain vardenafil

• Stendra^®, a newer, faster-acting ED medication containing avanafil

Is Viagra safe to use more than once a day?

Viagra is only designed to be taken once daily. Taking more than one dose of Viagra per day could increase your risk of experiencing side effects, drug interactions, and other safety issues.

How long does Viagra last?

Viagra lasts approximately four hours. It’s usually recommended to take it about 30 minutes to an hour before you plan to engage in sexual activity. We cover this topic in more detail in our guide to how long Viagra and other ED medications last.

Do lower doses of Viagra stop working faster?

Sildenafil, the active ingredient in Viagra, has a half-life of four hours, meaning it takes four hours for your body to metabolize half the medication. This half-life doesn’t change at a lower dose, meaning even a single dose of Viagra at 25mg should last about four hours, although the total concentration in your blood will be lower than if you took a higher dose.

Does age affect Viagra?

If you’re over 65, your healthcare provider may prescribe a lower dose of Viagra. Why? There’s evidence that after taking Viagra, older men will have higher amounts of it in their blood. Because of this, it’s important to listen carefully to your healthcare provider and closely follow their instructions.

Is Viagra prescribed by weight?

While there's a well-established link between ED and obesity, Viagra efficacy doesn’t appear to be affected by your weight.

Is It alright to take Viagra with food?

Viagra can be taken with or without food. However, taking Viagra with a large, high-fat meal may slow down the absorption of this medication, meaning it could take a little longer before you start feeling its effects.

Can Viagra cause side effects?

Viagra is safe and effective for most men with ED. But like all medications, it can cause side effects.

Our guide to Viagra side effects goes into more detail about various adverse effects and drug interactions that you should be aware of when using either brand-name Viagra or generic sildenafil. 

Can you overdose on viagra?

Taking an excessive dose of Viagra may result in a sudden drop in blood pressure, which could cause fainting. It’s important to make sure you don’t take more than the amount prescribed by your healthcare provider. 

If you’ve accidentally consumed more than the maximum safe dose of Viagra, it’s important to seek immediate emergency medical attention.

Does sildenafil (generic Viagra) dosage differ from Viagra?

Viagra and sildenafil both contain sildenafil, meaning you can use the same dose regardless of which medication you choose to take. Not only do sildenafil and brand-name Viagra work the same way, but they also cause the same potential side effects, interactions, and allergic reactions. 

The exception to this is if your sildenafil is actually the generic version of Revatio, which comes in 20mg tablets. Revatio is FDA-approved to treat PAH, but it (and its generic) are sometimes used off-label for ED.

What happens if you take a larger dose of Viagra than prescribed?

Taking a larger dose of Viagra than prescribed can be dangerous and isn’t recommended. Any Viagra dose higher than what you’re prescribed could increase your risk of potentially harmful side effects and drug interactions.

For instance, 200mg Viagra doses and higher could cause serious side effects, such as priapism (a painful, prolonged erection), vision loss in one or both eyes, hearing loss, and hypotension (low blood pressure).

Why won’t my healthcare provider prescribe Viagra?

Your healthcare provider will only prescribe Viagra if you’re a good candidate for it. This means that you:

• May benefit from Viagra to treat ED

• Have no health issues that could make Viagra unsafe

• Aren’t using any medications that could interact with Viagra

Viagra may cause drug interactions if you take other medications, such as riociguat or nitrates for chest pain, heart disease, or other cardiovascular issues. When used at the same time, these medications can cause a sudden decrease in blood pressure levels that may, in some cases, be life-threatening. A similar reaction can occur with nitrites, found in recreational drugs known as “poppers.”

Some medications, such as ritonavir, ketoconazole, itraconazole, and erythromycin, can affect your body’s ability to properly absorb and metabolize Viagra.

Viagra can also cause health problems for people with certain medical conditions, like high blood pressure, cardiovascular disease, heart failure, previous heart attacks, leukemia, multiple myeloma, and sickle cell anemia.

What happens if you miss a dose of Viagra?

Viagra is prescribed for use as needed before sex, meaning there’s no such thing as “missing” a dose. If you ever forget to take Viagra, you'll probably notice it — regretfully — immediately. That said, missing a dose of Viagra won’t have any long-term negative effects on your erections or sexual function nor will it affect your health in any way.

Viagra, as well as its generic equivalent, sildenafil, is an easy-to-use medication that makes getting and maintaining an erection a much simpler process.

As with other prescription drugs, there’s no single dose of Viagra that works best for every guy with ED. Your healthcare provider will work with you to figure out the best Viagra dosage for your needs, whether it’s 25mg, 50mg, or 100mg.

Here’s what to keep in mind:

• You’ll usually be prescribed a 50mg dose of Viagra to start. This is the typical starting dose of Viagra that produces improvements for most men with ED.

• Depending on your needs, your dosage may be adjusted to 25mg or 100mg. If you’re prone to side effects from Viagra, your healthcare provider may lower your dosage. If you have severe ED, it might be increased to 100mg.

• Make sure not to exceed your prescribed dosage. Taking too much Viagra or taking Viagra more than once a day isn’t recommended, as this can increase your risk of side effects and drug interactions.

Interested in using Viagra? We offer several evidence-based ED medications online, following a consultation with a healthcare provider, who will determine if a prescription is appropriate.

With Hims, you can meet with a licensed healthcare provider online and, if suitable for you, get access to proven medication to assist with erectile dysfunction as well as other common sexual performance issues.