Although Viagra is effective for most guys with erectile dysfunction (ED), not everyone’s erections will be as firm or reliable as they could be at too low of a dosage. Meanwhile, using too high a dosage of Viagra or its active ingredient, sildenafil citrate could result in side effects. So, what’s the right dosage?
How much Viagra should I take the first time? That’s a question your healthcare provider should answer for you, though typically your first dose will be 50 mg, taken as needed up to once a day.
That said, we can answer some general questions about this FDA-approved medication like: how it works, what common dosages you’re likely to see and what health conditions and medications you need to tell a healthcare professional about before they prescribe you Viagra.
Let’s start at square one. Viagra is a medication for treating erectile dysfunction. It’s available as a brand-name drug 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. These medications work by dilating the blood vessels that flow to your penis, which can improve blood flow and make it easier to get and maintain an erection when you’re in the mood for sex.
Erections are all about healthy blood flow. When you’re aroused, your nervous system sends signals to dilate the blood vessels that supply the penis, causing the corpora cavernosa (the erectile tissues inside your penis) to expand and harden as blood flows in.
By keeping the blood vessels dilated, Viagra makes this process easier and lets you focus on enjoying sex with your partner instead of worrying about your erection.
It’s important to keep in mind that Viagra only helps to reduce the severity of erectile dysfunction when you feel sexual stimulation. If you’re not aroused (or if you have erectile dysfunction due to a mental health issue), Viagra may not be fully effective at any dosage.
Our guide to erectile dysfunction goes into more detail about this, from how ED may affect your sexual function to physical and psychological factors that might restrict blood flow and stop you from getting an erection.
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. Your healthcare provider may start you on this dose if you have ED and want to try medication.
100mg. This is the highest 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 (20-milligram) dose as either brand-name Revatio® or its generic. Revatio® is a medication that is used to treat pulmonary arterial hypertension (PAH). By taking multiple tablets of Revatio® or generic Revatio®, it’s possible to achieve doses of 40mg, 60mg, 80mg, and 100mg, which approximate the doses of Viagra and generic Viagra. But you should only do this if it’s what a healthcare provider prescribed for you.
Viagra dosing can be a trial and error process. A healthcare provider might adjust your Viagra dosage by weight, age and other factors. The Viagra dosage for 70 year old men might beis different thanfrom the Viagra dosage for 50 year old men or it might be the same — it all depends on a variety of factors considered together.
Erectile dysfunction can vary significantly in severity. If you have mild to moderate ED, you may not have any major problems getting hard, but you might find it tough to maintain your erection while having sex.
If you have severe ED, you might find it difficult to get an erection at all, no matter how hard you try.
To get the best results from Viagra, it’s important to use a dosage suitable for you based on the severity of your symptoms, the side effects you might be experiencing and your general health and well-being.
If you have mild ED, or if you experience side effects when taking Viagra at a dose of 50mg or 100mg, your healthcare provider may suggest 25mg of Viagra.
Currently, 25mg is the lowest dose of Viagra approved by the FDA. It’s less likely to cause side effects than higher doses, all while providing relief from erectile dysfunction for the majority of men.
According to clinical trials, 63 percent of men who were treated with this dose of Viagra reported improved erections. Headaches, flushing and dyspepsia side effects were reported by 16, 10 and three percent of men, respectively.
Your healthcare provider might prescribe this dose if you also use other medications, such as alpha-blockers for hypertension or antiretroviral medications used to treat HIV.
This dose may also be prescribed if you’re older than 65 and/or have a chronic health issue, like kidney impairment or liver cirrhosis.
If you’re experiencing erectile dysfunction and want to start using medication to treat it, your healthcare provider will likely prescribe Viagra at a dose of 50mg for use around 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 dose over a period of 12 to 24 weeks.
This dose 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 the men who used Viagra at this dose in clinical trials, with 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 dose.
The Viagra max dose 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 shows that taking Viagra at a prescribed dose of 100mg is more likely to treat ED than other doses.
In fact, 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.
Taking Viagra at this dose also increases the risk of certain vision-related side effects, such as blurred vision, altered color vision and increased sensitivity to light.
You should never exceed a 100mg dose of Viagra. Don’t take Viagra more than once a day, and never take two Viagra pills at a time. And make sure to alert your healthcare provider if you still find it difficult to get or maintain an erection after using 100mg of Viagra.
There’s no one-size-fits-all dose of Viagra that works the best for everyone. If you have ED, your healthcare provider will choose a dosage of Viagra that’s appropriate for you after taking several factors into account, including:
If a different dose is or is not working for you
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
Following the medical advice of your healthcare provider is the best way to find a Viagra dosage to improve your erections and prevent sexual dysfunction with minimal side effects.
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, make sure to let your healthcare provider know.
If Viagra isn’t the right choice for you, your healthcare provider might recommend changing to a different ED drug better suited to your needs.
Common alternatives to Viagra include:
Cialis®, a longer-lasting ED medication nicknamed the “weekend pill” containing the active ingredient tadalafil
Stendra®, a newer, faster-acting ED medication containing avanafil that’s less likely to cause certain side effects
Having sex more than once a day is great. But Viagra isn’t the best option if you need more than one dose of medication a day to make sure you’re fully prepared for round two.
This is because 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.
Viagra lasts approximately four hours, although it’s usually recommended to take it about 30 minutes to an hour before you plan to engage in sexual activity. We covered this topic in more detail in our guide to how long Viagra and other ED medications last.
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 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.
If the effects of Viagra don’t last long enough for you to have satisfying sex, you may want to talk to your healthcare provider about switching to a longer-lasting ED drug such as Cialis.
If you’re over 65, your healthcare provider may prescribe you 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.
While there's a close, proven link between ED and obesity, Viagra efficacy doesn’t appear to be affected by your weight.
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.
Viagra is a safe and effective medication 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 you should be aware of while using either brand-name Viagra or generic sildenafil.
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 than the amount prescribed by your healthcare provider.
If you’ve accidentally consumed more than the maximum safe dose of Viagra, seek immediate emergency medical attention.
Viagra and sildenafil both contain the same active ingredient, meaning you can use exactly the same dose regardless of which medication you choose to take.
Not only do sildenafil and brand-name Viagra work exactly 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) can be used off label for ED.
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.
Viagra doses 200 mg and up could cause serious side effects. Serious side effects of Viagra include priapism (a painful, prolonged erection), vision loss in one or both eyes, hearing loss and hypotension (low blood pressure).
If Viagra doesn’t seem to work for you, don’t take more than your prescribed dose. Instead, talk to your healthcare provider. They may suggest adjusting your dosage of Viagra, making certain changes to the way you use this medication or switching to a different ED treatment.
Your healthcare provider will only prescribe Viagra if you’re a good candidate for it. This means that you:
Need Viagra to treat ED
Have no health issues that could make Viagra unsafe
Don’t use 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.
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.
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. However, it might lead to a disappointing night — at least until you’ve had time to find your medication and take it a little later than usual.
If you often forget to use Viagra before sex, you might want to talk with your healthcare provider about switching to Cialis. This ED medication is available as a daily-use pill you can take to get all-day relief from erectile dysfunction.
Making changes to the way you use Viagra might also make it easier to remember. Try:
Setting a reminder on your phone an hour before you plan to have sex to let you know that it’s time to take your medication
Taking Viagra before you go out on a date instead of right before you plan to have sex
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.
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’ll 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, premature ejaculation and other common sexual performance issues.
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