How Does ED Medication Work?

Katelyn Hagerty

Reviewed by Katelyn Hagerty, FNP

Written by Our Editorial Team

Published 09/14/2017

Updated 09/28/2023

Raise your hand if you’ve heard of Viagra®! We’d bet several of you raised your hands just now (figuratively, of course). Now, raise your hand if you deal with erectile dysfunction (ED). We imagine a lot fewer hands in the air.

While ED can be embarrassing, you may be relieved to know you’re not alone — approximately 30 million men in the U.S. have this condition.

So, whether you have ED or not, you’ve probably heard of Viagra, along with other erectile dysfunction medications (perhaps the names Levitra® or Avanafil® ring a bell). And while these medications are well-known, you might be wondering, How does ED medication work?

It’s good to ask questions, especially about any medications you may start using to help with ED — and even more so with unfamiliar ingredients. (For example: Is sildenafil a drug or another way to say “Bless you” when someone sneezes?)

Below, we’ll answer questions like, “How do ED pills work?” We’ll also go over what side effects these medications might cause, how fast they work and more.

How Do ED Pills Work?

If you think getting an erection is as simple as an erotic Internet search, think again. A complex process goes on behind the scenes involving multiple parts and systems to achieve and maintain an erection.

Oh, and don’t think uncomplicated erectile function is only for the young and healthy. Several medical conditions like heart disease and diabetes can cause ED, not to mention mental health issues, such as performance anxiety, and various lifestyle factors.

Luckily for you (and the millions of other men who find this health condition interfering with their sex life), ED treatment options are available.

A number of medications have been approved for the treatment of erectile dysfunction by the U.S. Food and Drug Administration (FDA), including:

While these are often offered as oral medications, chewable ED meds like our hard mints provide a fresh and convenient way to treat ED — and they contain the same active ingredients in Viagra and Cialis.

Currently, all these FDA-approved ED pills are prescription medications that can’t be bought over the counter, unlike the sketchy sex pills you see at the gas station.

But how do ED pills work? To understand how erectile dysfunction medication works, let’s first take a quick look at how erections work.

Erections typically begin with sexual stimulation, whether physical or mental. This triggers an internal process involving your nervous and cardiovascular systems.

The nerves inside your penis “tell” the muscles in your penis through neurotransmitters (naturally occurring chemicals) to relax and let the blood vessels widen to allow more blood flow.

All the ED drugs we mentioned belong to a class of medications called PDE5 inhibitors, short for phosphodiesterase type 5 inhibitors. They increase blood flow to the tissue inside your penis, making it easier to get an erection after sexual stimulation.

There’s a reason sildenafil, tadalafil and other PDE5 inhibitors are some of the most common ED treatments — they work.

Tadalafil, for example, significantly enhanced erectile function as well as sexual activity in men of different ages throughout clinical trials.

From the newer generation of ED drugs, avanafil has shown to be just as effective at improving erectile function as older medications like sildenafil, tadalafil and vardenafil.

And there’s a reason Viagra is a popular ED medication — 82 percent of those taking a 100-milligram (mg) dosage saw improvement in their erections.

All these medications work effectively, and they’re some of the safest ED drugs, thanks to ongoing testing and approval by the FDA. That said, there’s still a chance of experiencing side effects and some risks (that come with taking any medication, really).

We’ll get into the side effects and risks below.

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How Quickly Do ED Medications Work?

Though the amount of time it takes erectile dysfunction pills to work varies among individual medications, most sexual dysfunction drugs take 30 to 60 minutes to start working with sexual stimulation.

It’s recommended to take Viagra, for example, one hour before sexual activity, as it can take between 30 and 60 minutes for the medication to reach its highest concentration.

Cialis, on the other hand, reaches peak concentration anywhere between 30 minutes and six hours after taking it. It should be taken two hours before sexual activity.

However, the newer medication avanafil (and brand-name Stendra) works the fastest — between 15 and 30 minutes. Avanafil is the only fast-working FDA-tested and approved ED drug, despite what fast-acting male enhancements are being pushed these days. 

And those herbal or dietary supplements you see marketed for sexual dysfunction, often on display at gas stations or bought from sketchy websites? We’d pass on them.

While we often associate the words “herbal” and “natural” as being harmless or even better for us, these over-the-counter (OTC) products contain counterfeit ingredients that aren’t safe or effective.

Learn more about why OTC ED drugs are risky in our article.

Regardless of the specific medication you use, it’s best to take your ED medication about an hour before you plan to have sex. Prepare ahead of time, and you’ll experience the medication’s full effects when you and your partner become intimate.

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How Long Do ED Meds Last?

So you’re interested in using Viagra, avanafil or another ED med. But how long will it last?

To understand how long an ED medication will last, you need to know its half-life. A drug’s half-life is how long it takes for the concentration of the medication in your body to fall to half of its peak. The half-life of a medication determines how long it’ll remain active in the body.

For example, a normal 50-milligram dose of sildenafil (Viagra) will be reduced to a potency of approximately 25 milligrams after one half-life has passed.

Here’s a list of both the half-lives and duration of action for four of the most common ED drugs (PDE5 inhibitors):

  • Viagra (or sildenafil) lasts three to five hours after it’s consumed.

  • Cialis (tadalafil) has a half-life of 17.5 hours, meaning this drug lasts up to 36 hours after it’s consumed.

  • Levitra (or vardenafil) has a half-life of four to five hours and remains active in the body for up to six hours after it’s consumed.

  • Stendra (or avanafil) has a half-life of three to five hours and remains active in the body for up to six hours after it’s consumed. This gives it an effective period similar to vardenafil and a slightly longer half-life than sildenafil.

As you can see, tadalafil is by far the longest-lasting of the four ED medications currently on the market. However, all men react differently to each medication.

The information packets and FDA guidelines for these medications, including Viagra, recommend seeking medical advice from a healthcare provider if your erection lasts longer than four hours — or if your erection doesn’t go away on its own (a condition called priapism).

Ask your healthcare provider for more information about the half-lives of these pills. We compared Cialis versus Viagra and Stendra versus Viagra for a more detailed look at some of the more popular ED meds.

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Common Side Effects of ED Meds

Now you know the answer to “How does ED medication work?” as well as how quickly and how long these pills typically last. It’s also crucial to know about the possible side effects of ED meds and the risks.

Side effects may vary slightly among medications. But since they work similarly, there are some common side effects, including:

  • Mild headaches

  • Dizziness

  • Muscle aches or back pain 

  • Nasal congestion

  • Facial flush

  • Vision issues, including temporary blurry vision 

  • Digestive issues or upset stomach

  • Rhinitis

As a newer, second-generation ED med, Stendra may be less likely to cause side effects or other serious issues compared to older medications like Levitra.

But just as every guy can experience different effectiveness with different medications, some may experience more or fewer side effects of ED meds than others. We covered all side effects of Viagra and common side effects of tadalafil in these guides.

There are also some potentially serious side effects of ED meds to know about, including drug interactions.

All ED medications currently available can cause slightly lower blood pressure levels, thanks to their effects on smooth muscle tissue and blood flow to penile blood vessels. This low blood pressure is mild and isn’t the underlying cause of any dangerous side effects on men’s health.

That said, if you use nitrates for angina (chest pain) or alpha-blockers and certain other medications to treat hypertension (high blood pressure), the reduction in blood pressure caused by ED medications can be dangerous. 

If you use any nitrates, it’s highly recommended that you don’t use sildenafil, tadalafil, vardenafil, avanafil or other similar medications.

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Understanding How ED Pills Work

While erectile dysfunction is a common health condition, several erectile dysfunction treatments are available. But how do ED pills work?

  • The most common erectile dysfunction medications are a type of drug called PDE-5 inhibitors. They work to help the blood vessels in your penis widen, allowing more blood flow for stronger and longer-lasting erections. Research shows that, when used properly, ED pills can help improve erectile function.

  • Many of these pills work fairly quickly. Sildenafil (Viagra), tadalafil (Cialis) and vardenafil (Levitra) typically start working within 30 to 60 minutes, while avanafil (Stendra) works within 15 to 30 minutes.

  • ED medications aren’t without the possibility of side effects. Some of the most common side effects of ED meds include headaches, dizziness, upset stomach, back pain and nasal congestion.

A healthcare provider can help you determine which ED medication and dose is right for you. You can also learn about more erectile dysfunction treatments in our guide.

12 Sources

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references.

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This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.

Katelyn Hagerty, FNP
Katelyn Hagerty, FNP

Kate Hagerty is a board-certified Family Nurse Practitioner with over a decade of healthcare experience. She has worked in critical care, community health, and as a retail health provider.

She received her undergraduate degree in nursing from the University of Delaware and her master's degree from Thomas Jefferson University. You can find Katelyn on Doximity for more information.

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