How long does Viagra take to work?

More than 30 million men worldwide take Viagra (sildenafil) to manage their erectile dysfunction (ED). Viagra (sildenafil) was the first drug of its kind to treat ED, and it continues to stay popular for its reliability to help keep strong erections. 

If you’re considering taking Viagra, you may already know a little bit of planning is required before you have sex. But, how much planning, exactly? Generally, Viagra kicks in within 30–60 minutes, but there are a few factors that can either speed up or slow down that timeframe. Read on to find out.

In general, the makers of Viagra recommend taking it about 1 hour before you plan on having sex. However, studies suggest that it may start working even sooner than that. For a majority of men, Viagra starts working within 30 minutes, although your mileage may vary. For some men, Viagra kicks in after just 12 minutes, while for others it can take a bit more than an hour. 

It’s worth noting that most men studied take Viagra in a fasting state. Viagra can be taken with or without food, but it may take longer to work if you take it after eating a high-fat meal, such as a cheeseburger and french fries. In clinical studies, taking Viagra with a high-fat meal delayed its effects by about 1 hour, on average.

As a reminder, you need to be sexually aroused in order for Viagra to work. It does not make you horny. It enables you to get and maintain an erection once you’re already feeling aroused.

How long does Viagra last?

While it usually starts working within 30–60 minutes, Viagra can last for up to 4 hours, on average. As long as you take Viagra within 4 hours of when you plan on having sex, you should most likely be good to go.

One way to prevent Viagra from working slower is to avoid taking it after eating a high-fat meal, which can delay its effects by up to 1 hour. Consuming grapefruit or grapefruit juice may also slow down how fast Viagra works. Taking other medications that are known to affect the way your body metabolizes drugs could have an impact, too. 

Besides a few exceptions, whether or not you choose to eat before your Viagra dose should not make too much of an impact, as long as you avoid high-fat meals. 

It’s also possible that different forms of sildenafil, the active ingredient in Viagra, may help Viagra work faster. For example, sublingual sildenafil is a form of Viagra that you take under your tongue, such as a tincture, lozenge, melt, or spray. Ro Sparks is one such form of sublingual ED medication. It combines sildenafil with tadalafil, the active ingredient in Cialis and typically starts working within 15 minutes. 

Drugs that are taken sublingually offer some advantages over traditional oral ED medication — namely, that they don’t have to go through the digestive process, so they get absorbed into the bloodstream much more quickly. In one study, men who took sublingual sildenafil got hard within 15.5 minutes, on average, which is nearly twice as fast as the typical onset for Viagra. 

Because Viagra works so discreetly, there aren’t necessarily any telltale signs that it’s working — until you start getting hot and heavy, that is. Once you start fooling around, you should be able to tell that the Viagra is working. Your penis may feel harder than normal. Or, maybe you’ve had trouble staying hard in the past, and now you don’t after taking Viagra. Your erections stay hard longer. For example, in small studies of men with ED, those who took Viagra sustained erections for 19.5–26 minutes on average, compared with an average of 0–7 minutes for those who took a placebo. 

While this isn’t an FDA-approved reason to use Viagra, you may also enjoy a shorter refractory period than you normally do — even past the advertised 4-hour time limit, though studies differ. One study found that 40% of male participants with an average age of 32 years old reported that taking sildenafil reduced the refractory period. It was shortened from a median time of 14.9 minutes to 5.5 minutes—a reduction of 9.4 minutes. However, another study found that taking sildenafil made no difference in the length of the refractory period.

While Viagra typically works its magic in a lowkey, incognito way, you may get a heads-up that it’s kicked in if you experience some of its side effects. In clinical trials, up to 28% of men taking Viagra got a headache, up to 18% experienced facial flushing, and up to 17% had an upset stomach or indigestion. Side effects are more common on the higher 100 milligrams (mg) dosage of Viagra than on the lower 50 mg dosage. Common side effects of Viagra can include:

• Headache

• Flushing

• Upset stomach or indigestion

• Abnormal vision, such as a color tinge, blurred vision, or increased sensitivity to light

• Nasal congestion

• Back pain

• Muscle aches or pain

• Nausea

• Dizziness

• Rash 

Viagra’s side effects are typically transient and range from mild to moderate. The medication is safe and well-tolerated by most men, but it is possible to experience a serious side effect that requires medical treatment. If you notice any of the following, stop taking Viagra and seek medical care immediately:

• A prolonged, potentially painful erection lasting 4 or more hours

• A sudden loss of vision in one or both eyes

• A sudden decrease or loss of hearing

The decision is yours, as Viagra can be taken with or without food, according to the instructions on the FDA label. However, if you want to have sex sooner vs. later, you may want to avoid eating certain types of food with Viagra. High-fat meals, such as burgers and fries, can delay the effects of Viagra by up to 1 hour, give or take. If you avoid high fat meals, taking Viagra with food does not significantly delay its effects from kicking in.

Grapefruit (and grapefruit juice) may be another food to avoid while taking Viagra. Grapefruit has the ability to affect the absorption of many prescription drugs, including Viagra. While it probably won’t create a dangerous drug interaction, mixing Viagra with grapefruit or grapefruit juice may delay the absorption of the medication and cause it to take longer to start working.

What about alcohol? In low amounts, alcohol may not affect how long it takes for Viagra to start working.

If you’ve tried Viagra a few times and you’re not getting the results you wanted, talk to your healthcare provider. They may recommend adjusting your dosage of Viagra. If Viagra still doesn’t work, you have several other options you can try. In general, PDE-5 inhibitors are considered to be an effective class of drugs, and if the first one doesn’t work, the next one you try very well might — which happens to many men. Other options besides Viagra include:

• Other oral PDE5 inhibitors: The class of drugs Viagra belongs to also includes Cialis (tadalafil), Stendra (avanafil), and Levitra (vardenafil). Side effects are similar amongst PDE5 inhibitors, with headache, flushing, and indigestion being most common. They’re usually taken the same way as Viagra, by mouth, usually 15–60 minutes before sex. One standout amongst these is Cialis, which can be taken as needed like the others, but can also be taken daily for those who want more spontaneity. This medication lasts up to 36 hours. 

• Compounded ED medication: Compounded ED medications are prepared by a specialized compounding pharmacy to create variations of a medication that better suits the needs of a particular patient. Compounded ED medications may come in different forms other than the typical oral tablet, such as a sublingual form. They may also combine more than one active ingredient One example of this is Ro Sparks, which combines sildenafil and tadalafil, the active ingredients in Viagra and Cialis, respectively.

• Other strategies for ED: Natural strategies for ED include a range of possibilities, from lifestyle changes, like quitting smoking and diet and exercise. Other options for ED may include numbing gels and penis pumps.

The best ED treatment for you can depend on several factors, from side effects to price point and convenience. Ask your healthcare provider about your options, and be sure to provide your personal medical history and any medications or supplements you are currently taking.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

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Current version

April 16, 2024

Written by

Amelia Willson

Fact checked by

Raagini Yedidi, MD

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About the medical reviewer

Raagini Yedidi, MD

Raagini Yedidi, MD, is an internal medicine resident and medical reviewer for Ro.