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

Struggling to get an erection after taking Viagra®? Erectile dysfunction (ED) is a common issue that can vary in severity, making it important to find the right dose if you use medication to help with getting and maintaining an erection.

Viagra, which contains the active ingredient sildenafil citrate, is available in three doses. If you’re prescribed Viagra and aren’t getting results from your current dose, switching to a different dose may help you to maintain an erection more easily and have more satisfying sex. 

Below, we’ve covered what Viagra is, as well as how it works as a form of treatment for erectile dysfunction.  

We’ve also listed common doses of Viagra, explained how to find the right dose for your needs and answered some common questions about using Viagra safely and effectively.

What is Viagra?

Viagra is a common medication for treating erectile dysfunction. It’s available as a brand name drug and as a generic medication -- typically at a much lower cost per tablet -- as sildenafil.

Viagra belongs to a class of drugs called PDE5 inhibitors, which work by blocking the effects of the PDE5 enzyme.

This enzyme is responsible for regulating blood flow to several types of tissue throughout your body, including the erectile tissue inside your penis. When PDE5 is active, it limits the diameter of your blood vessels and restricts blood circulation to your penis.

By preventing PDE5 from regulating blood flow, medications like Viagra increase the supply of blood to the erectile tissue inside your penis.

Erections are all about healthy blood flow. When you’re aroused, your nervous system sends a series of signals to the tissue in your penis, causing the ​​corpora cavernosa (the erectile tissues that make up your penis) to expand and harden as blood flows in.

By stimulating blood flow, Viagra makes this process easier and allows you to focus on enjoying sex with your partner instead of worrying about your erection.

Our guide to erectile dysfunction goes into this process in more detail, from how ED may affect your sexual function to physical and psychological factors that may restrict blood flow and stop you from getting an erection. 

Available Viagra Dosages

Erectile dysfunction can vary significantly in severity. Some men with mild or moderate erectile dysfunction have no problems getting an erection, but may find it challenging to stay hard while having sex with their partner.

Others may find it difficult or impossible to get an erection at any time, even with a lot of sexual stimulation.

To get the best results from Viagra, it’s important to use a dosage that’s suitable for you based on the severity of your symptoms and your general health and wellbeing. 

Viagra comes as an oral tablet and is available in three dosages, ranging from 25mg to 100mg per tablet. 

Viagra 50mg: A Typical Starting Dose of Viagra

The typical starting dose of Viagra or generic sildenafil is 50mg. If you have erectile dysfunction and want to start using medication to treat it, your healthcare provider will likely prescribe Viagra at a dose of 50mg, taken approximately one hour before sex.

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 dosage over a period of 12 to 24 weeks. 

This dosage of Viagra offers a good mix of benefits and tolerable side effects. Headaches -- the most common side effect of Viagra -- were reported by 21 percent of men who use Viagra at this dosage in clinical trials, with facial flushing reported by 19 percent.

Other side effects are usually mild and are only reported by a small percentage of men who take Viagra at this dosage.  

It’s important to keep in mind that Viagra only helps to reduce the severity of erectile dysfunction when you feel sexually aroused. If you’re not aroused, or if you have erectile dysfunction from a mental health issue, Viagra may not be fully effective at any dosage.

Viagra 100mg: The Maximum Dose of Viagra

The maximum dose of Viagra that is approved by the FDA is 100mg. Your healthcare provider may prescribe Viagra at this dosage 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. 

Research shows that taking Viagra at a prescribed dose of 100mg is more likely to prevent ED, but that it may increase your risk of experiencing certain adverse effects.

In trials of Viagra, 82 percent of men who used a 100mg dose of sildenafil (the active ingredient in Viagra) reported improvements in their erections. However, side effects such as headaches, flushing and dyspepsia (indigestion) were all reported by a larger percentage of users.

Taking Viagra at this dosage also increases the risk of several vision-related side effects, such as blurred vision, altered color vision and loss of vision due to increased sensitivity to light.

You should never exceed a 100mg dosage of Viagra. Do not take Viagra more than one time a day, and never take two Viagra pills at a time. Make sure to alert your healthcare provider if you still find it difficult to get or maintain an erection after using 100mg of Viagra.

Viagra 25mg: The Lowest Dose of Viagra

If you have mild erectile dysfunction, or if you experience side effects when you take Viagra at a dosage of 50 or 100mg, your healthcare provider may suggest taking 25mg of Viagra.

Currently, 25mg is the lowest FDA-approved dose of Viagra. Used as-needed before sex, 25mg of Viagra is generally effective at treating ED and has a lower risk of producing side effects than higher dosages. 

According to clinical trials, 63 percent of men who were treated with this dose of Viagra reported improved erections. Side effects, such as headaches, flushing and dyspepsia, were reported by 16, 10 and three percent of men, respectively. 

Your healthcare provider may also suggest this dosage if you’re also currently prescribed other medications that can affect your body’s ability to metabolize Viagra, such as alpha-blockers for hypertension or antiretroviral medications used to treat HIV. 

This dosage may also be prescribed if you’re older than 65 years of age and/or have a chronic health issue such as kidney impairment or liver cirrhosis. 

How to Find the Right Viagra Dose for You

Because erectile dysfunction can vary so much in severity, there’s no one-size-fits-all “perfect” dose of Viagra for everyone. 

If you have erectile dysfunction, your healthcare provider will choose a dosage of Viagra that’s suitable for you based on your general health, the severity of your symptoms, any medications you currently use and other factors. 

If you have mild to moderate ED and don’t have any relevant health conditions, your healthcare provider will likely prescribe Viagra at a dosage of 50mg. 

You may need to take Viagra several times to assess if it works well for you. If you develop any side effects while using Viagra at this dosage, or don’t seem to notice any results, it’s important to let your healthcare provider know.

It may take several months to “dial in” your dosage of Viagra. Alternatively, if Viagra just isn’t the right choice for you, your healthcare provider might recommend changing to a different ED drug that’s better suited to your needs.

Common alternatives to Viagra include Cialis®, a longer-lasting ED medication that contains the active ingredient tadalafil, and Stendra®, a new ED medication that’s less likely to cause certain side effects. 

Following the medical advice of your healthcare provider is the best way to find a Viagra dosage that prevents sexual dysfunction with minimal side effects. 

Frequently Asked Questions About Viagra Dosages

Is Viagra Safe to Use More Than Once a Day?

The maximum dosing frequency for Viagra and generic sildenafil is one time per day. Viagra is not designed for use more than one time a day. Taking more than one dose of Viagra per day may increase your risk of side effects, drug interactions and other safety issues.

How Long Does Viagra Last?

Viagra lasts for around four hours, although it’s usually recommended to take it about an hour before anticipated sexual activity. We’ve covered 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 terminal half-life of four hours, meaning it takes four hours for your body to metabolize half of the medication. This half-life does not change at a lower dose, meaning even a single dose of Viagra at 25mg should last for about four hours.

However, due to age-related changes in your body, you might notice the effects of the 25mg and 50mg doses of Viagra fading away earlier than the higher 100mg dose. 

If the effects of Viagra don’t last for a long enough amount of time for you to have satisfying sex, you may want to consider talking to your healthcare provider about switching to a longer-lasting ED drug such as Cialis. 

Does Age Affect Viagra?

Age does not generally affect Viagra’s effectiveness. However, if you’re above 65 years of age, your healthcare provider may prescribe you a lower dose of Viagra, since there’s evidence that after taking Viagra, older men will have higher amounts of it in their blood.

In a nutshell, the Viagra dosage for a 70 year old likely won’t be the same as the Viagra dosage for 20 year olds. Because of this, it’s important to listen carefully to your healthcare provider and closely follow their instructions. 

Is Viagra Affected by Weight?

While obesity and erectile dysfunction do appear to have a positive correlation, Viagra efficacy does not appear to be affected by weight, meaning you shouldn’t need to take a higher dose if you’re tall or have a heavy build.

Most of the time, even if you have an above-average body weight, your healthcare provider will recommend starting with a 50mg dosage of Viagra.

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 can slow down the absorption of this medication, meaning you may need more than one hour to feel its effects.

Can Viagra Cause Side Effects?

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

Common side effects of sildenafil and brand-name Viagra include headaches, back pain, nasal congestion, dizziness, facial flushing, indigestion, nausea, visual disturbances and changes in your blood pressure levels.

In rare cases, Viagra and generic sildenafil may also cause priapism, decreased vision, sudden changes in your hearing and other issues. You may have an elevated risk of side effects if your Viagra dosage causes you to have high levels of sildenafil in your body.

Our full guide to Viagra side effects goes into more detail about side effects and interactions to be aware of while using either brand-name Viagra or generic sildenafil. 

Can You Overdose on Viagra?

How much Viagra (sildenafil) is too much? Taking an excessive dose of Viagra may result in a sudden drop in blood pressure, which could cause fainting. Make sure not to take more Viagra than the amount you’re prescribed by your healthcare provider.

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

Do Doses of Sildenafil and Viagra Differ?

Viagra and generic sildenafil both contain the same active ingredient, meaning you can use the exact same dose for the treatment of erectile dysfunction with generic sildenafil as you would if you were using brand-name Viagra.

Not only do generic sildenafil and brand-name Viagra work in exactly the same way -- they also have an identical range of potential side effects and allergic reactions. 

Viagra Doesn’t Work For Me. Should I Increase the Dosage?

A variety of factors can cause Viagra to not work, from the severity of your erectile dysfunction to your general health. If you don’t experience any improvements from your starting dosage of Viagra (or initial sildenafil dose, if you’re prescribed a generic), tell your healthcare provider.

They may increase your dosage (for example, from 50mg to 100mg or 25mg to 50mg) and ask you to monitor your results. Do not increase your dosage of Viagra without first consulting your healthcare provider. 

Why Won’t My Healthcare Provider Prescribe Viagra?

If your healthcare provider won’t prescribe Viagra or generic sildenafil for erectile dysfunction, it may be because they have a good reason. 

Viagra may cause problematic drug interactions if you take other medications, such as riociguat or nitrates for chest pain, heart disease or other cardiovascular issues. 

When used together, these medications can trigger a sudden decrease in blood pressure levels that may, in some cases, be life-threatening.

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

If you also have benign prostatic hyperplasia (BPH), your healthcare provider may prescribe a different PDE5 inhibitor, such as Cialis, which is approved for the treatment of benign prostatic hyperplasia and pulmonary arterial hypertension. 

What Happens if You Miss a Dose of Viagra?

Viagra is prescribed for use as needed, meaning you only need to use it if you plan to have sex within the next few hours. 

If you miss a dose of Viagra, you may notice that you’re less able to get or maintain an erection during sex. If you have moderate to severe ED, you might find it difficult to get an erection at all, even with significant sexual stimulation. 

However, 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 meaningful way. 

If you often forget to use Viagra before sex, making some changes to the way that you use your medication might make it easier to remember. 

This could mean taking Viagra before a date instead of just before sex, or scheduling a reminder to let you know that it’s time to take Viagra about an hour before you typically have sex with your partner. 

Alternatively, it could mean switching to a different ED treatment that’s longer lasting or easier to take with meals. 

The Bottom Line on Finding the Right Viagra Dose

If you’re affected by erectile dysfunction, using medication like Viagra can make it easier to get and maintain an erection. 

Finding the correct dose of Viagra is important for ensuring you have safe, consistent levels of sildenafil in your body during sexual activity, as well as reducing your risk of experiencing side effects. 

Make sure to follow your healthcare provider’s instructions and take Viagra at the dose you’re prescribed. Inform your healthcare provider if you think your Viagra dose is too high and likely to cause side effects or too low to provide proper relief from ED.

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.

Using 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, premature ejaculation and other common sexual performance issues.