Viagara can take about a half hour to start working and may work for a couple of hours, or longer, depending on certain factors, including your metabolism.

Sildenafil is a common medication used to stimulate erections in people with erectile dysfunction (ED). It can also treat pulmonary arterial hypertension (high blood pressure affecting the lungs and heart).

For treating ED specifically, Viagra is the well-known brand-name version of this drug.

Many factors can influence how long Viagra takes to start working. In general, Viagra takes about 30 minutes to produce noticeable effects.

But your diet, your overall health, the medications you’re taking, underlying conditions, and much more can all affect the amount of time Viagra takes to work in your body and how long it lasts.

An erection happens when nerves in your penis are stimulated.

As a result, muscles around two cylinder-shaped chambers of spongy material along your penis, known as the corpora cavernosa, relax and allow blood to flow in, causing an erection.

With ED, your nerves don’t communicate properly with your brain and blood doesn’t flow properly into the corpora cavernosa. Taking Viagra relaxes the walls of your blood vessels and lets blood flow more easily into the parts of your penis that cause an erection.

Viagra normally starts working 30 to 60 minutes after you take it in oral tablet form. It may take up to 2 hours to work.

Viagra doesn’t work on its own. You’ll still need to feel sexually aroused to get an erection. Feeling relaxed and comfortable can also help Viagra take effect sooner.

On average, Viagra lasts between 2 and 3 hours before its effects start to diminish. Viagra can last up to 5 hours or longer depending on your dosage, your body’s metabolism, and other external factors.

Depending on how your body metabolizes it, you may be able to get an erection several times with Viagra in your system. Viagra probably won’t make you last longer in bed, though. No research has proven definitively that Viagra can increase how long you can have sex.

Viagra may not work again immediately after you’ve had sex. Normally, you can’t get another erection right after ejaculating because your body isn’t physically prepared for it.

This is known as the refractory period. It may only last a few minutes, but it can last as long as a few hours or days. However, a 2000 study found that Viagra may decrease this recovery time.

Several important factors can influence how long Viagra lasts for you:

  • Dosage. The amount of Viagra you take affects how long it stays in your system. The smallest available dose, 25 milligrams (mg), won’t last as long as the largest available dose, 100 mg. But taking a higher dose isn’t always recommended, as it may not be safe for you.
  • Age. As you get older, your metabolism slows down. So Viagra may last longer as you age. In general, you may notice Viagra works for a longer period when you’re 65 or older.
  • Diet and lifestyle. Eating a large meal or a lot of high-fat foods right before you take Viagra can keep it from being metabolized quickly or effectively. But this can also make it last longer as it’s metabolized along with your meal. Drinking alcohol or smoking can also decrease blood flow to your penis, making Viagra less effective or shorter-lasting.
  • Medications. Some medications, especially antibiotics such as erythromycin (Ery-Tab), clarithromycin (Biaxin), and ciprofloxacin (Cipro), can interact with Viagra and affect how long it lasts.
  • Overall health. Certain existing conditions can affect how long Viagra lasts and how well it works for you. Diabetes, nervous system conditions like multiple sclerosis (MS), and heart conditions like atherosclerosis (fat buildup in your blood vessels) can all make Viagra less effective and not last as long. Some kidney conditions may make Viagra last longer because of the condition’s effect on your metabolism.
  • Psychological state. Feeling anxious, nervous, depressed, or stressed can all influence how your body responds to sexual stimulation. If you’re not relaxed or comfortable during sex, or if you have performance anxiety because of past sexual experiences, Viagra may not last long or be fully effective.

Viagra usually leaves your system after 2 to 3 hours. Depending on your metabolism, Viagra can take 5 to 6 hours to fully leave your system.

A higher dosage will take longer to leave your body. A 25-mg dose may wear off after a couple of hours, but a 100-mg dose may take nearly four times as long to leave your system.

Viagra often lasts for a few hours. You won’t normally have an erection the entire time, as Viagra is only used to help increase blood flow. If you don’t think Viagra is working fast enough, try masturbation or foreplay to help stimulate arousal.

If Viagra doesn’t work after 30 minutes, don’t take any more than the daily dose that your doctor prescribed. Never take more than 100 mg of Viagra in a 24-hour period.

Too much Viagra can cause severe headache, low blood pressure, and orthostasis (drop in blood pressure when standing) that can lead to fainting.

Higher doses can also cause priapism, a painful erection that lasts longer than 4 hours. This can damage penis tissue because blood stored in the penis isn’t receiving any oxygen. Get emergency treatment right away if this happens.

Talk with your doctor before you take Viagra or any related medication for ED. It’s important to take a safe dose and work out a clear understanding of how much you should take in a 24-hour period.

Some medications for heart conditions, such as nitroglycerin and other nitrates, can interact dangerously with Viagra and cause your blood pressure to drop too low.

If Viagra isn’t working or isn’t safe for you, talk with your doctor about other possible treatments for ED, such as:

  • penis pumps
  • penile implants
  • intracavernosal injection (ICI)
  • intraurethral gels or pellets
  • exercises
  • therapy for anxiety, depression, or other similar conditions

Viagra typically starts working within 30 to 60 minutes and lasts for about 2 to 3 hours after that.

Seek medical attention if you experience an erection lasting longer than 4 hours.