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Erectile dysfunction (ED) may affect as many as 30 million men in the United States. People with ED experience an inability to get or keep an erection firm enough for sex.

You may be familiar with some of the more common treatments for ED, including lifestyle modifications, oral medications that include phosphodiesterase type 5 inhibitors (PDE5 inhibitors), and penis pumps.

A 2018 study also looked at the use of nitroglycerin gel or cream as a topical treatment for ED. Although results look promising, it’s important to note that nitroglycerin gel or cream isn’t approved by the Food and Drug Administration (FDA) to treat ED.

Here’s what you need to know about nitroglycerin as a topical treatment for erectile dysfunction.

Language matters

In this article, we talk about nitroglycerin for the treatment of ED. Throughout the article, we use “men” to reflect a term that has been historically used to gender people.

While we aim to create content that includes and reflects the diversity of our readers, specificity is key when reporting on research participants and clinical findings.

The studies and surveys referenced in this article did not include data on, or include, participants who were transgender, nonbinary, gender nonconforming, genderqueer, agender, or genderless.

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Nitroglycerin is part of a class called vasodilators, which widen the blood vessels and improve blood flow to allow oxygen-rich blood to reach the heart.

It comes in a variety of forms, including a sublingual (under the tongue), topical cream or gel, and a transdermal patch. Nitroglycerin is most often used to prevent angina or attacks of chest pains.

“The idea of treating ED with topical nitroglycerin is not new and was first described in the 1980s,” says Dr. Joseph Brito, a urologist at Yale New Haven Health, Lawrence + Memorial Hospital. Brito is also a member of Healthline’s clinical review network.

In general, Brito says nitroglycerin works by dilating the blood vessels, which is why it’s traditionally used for people with angina or chest pain due to poor cardiac vessel blood flow.

The concept is the same for ED, although Brito says it may have a dual mechanism of action:

  • It widens blood vessels, which helps blood flow.
  • It relaxes penile smooth muscle, which compresses penile veins and impedes blood flow out of the penis, causing rigidity.

“[Topical nitroglycerin] acts as a nitrogen donor to increase local levels of nitric oxide, which works through molecular signaling (cGMP pathway) to cause this response,” he says.

On the other hand, Brito says PDE5 inhibitors (like tadalafil and sildenafil) work at a later step in the chain by inhibiting the breakdown of cGMP.

That said, Brito points out that nitroglycerin gel or cream is currently not approved by the FDA to treat ED. Older studies have found that nitroglycerin gel can enhance blood flow to the penis, but this increased blood flow may not be enough to sustain an erection.

Brito points out that the American Urological Association guideline on ED published in 2018 (the most recent published guidelines) didn’t include topical nitroglycerin as a suggested treatment for men with ED.

“Though this therapy was not specifically mentioned, the authors did state that “the use of these treatments may preclude the use of other treatments known to be effective,’ and felt more research was needed,” he explains.

There isn’t much research related to nitroglycerin gel and ED treatment. However, the 2018 study mentioned above found that 23% of users with ED experienced improved erections using a 0.2% nitroglycerin gel. Those with mild ED experienced the most significant effects.

There’s another factor to consider: Nitroglycerin cream applied to the outside of the penis may transfer to your partner. Older reports of nitroglycerin use for ED have linked nitroglycerin gel use with an increased risk of headaches by both the person applying the gel and their partner.

“Nitroglycerin may have some benefits over standard oral ED medications,” Brito says.

The onset of topical nitroglycerin is between 10 and 20 minutes, which Brito says is better than the quickest acting oral agents, with sildenafil taking at least 30 minutes.

In fact, the 2018 study mentioned above found that 44% of people had an erection beginning within 5 minutes of application. About 70% of the men noticed an erection within 10 minutes.

The randomized, double-blind, placebo-controlled study included 232 men with ED who participated in two 4-week trials. One trial used a 0.2% glyceryl trinitrate topical gel before sex, and the other used a placebo gel.

“This may help with spontaneity, which can be an issue for couples using oral agents,” Brito explains.

Another benefit, Brito says, is that unlike other ED treatments like oral agents, nitroglycerin doesn’t need to pass through the gastrointestinal tract.

“Since absorption of oral agents like sildenafil is strongly affected by food intake, the medications are much more effective when taken on an empty stomach,” he says. This requires more planning and doesn’t always allow for spontaneity.

Nitroglycerin gel or cream is currently not approved by the FDA to treat ED.

If you have questions about this topical treatment, talk with a doctor who knows your medical history. A prescription is needed for nitroglycerin.

Nitroglycerin use is managed by your doctor. Don’t use or apply this topical treatment without guidance.

According to the 2018 study, the concentration studied was 0.2%, which Brito says likely explains why the effect was best for men with mild ED.

He also points out that other studies used concentrations of 0.2% to 0.8% for people with more severe ED, who likely need higher concentrations.

In general, Brito says people prescribed nitroglycerin by their doctor should apply a pea-sized amount to the head of the penis.

We have mentioned this before, but it’s worth repeating: The FDA hasn’t approved nitroglycerin gel applications for ED. As a result, there isn’t a safe dosage recommendation for topical treatments. It’s also hard to control an exact dose of a topical medication because it’s not as easily measurable as a pill or liquid.

Nitroglycerin gels applied to the penis can range in strength from 0.2% to 0.8%. These doses are smaller than the nitroglycerin paste or gel applied to the chest for chest pain, which is a 2% paste. It’s important not to mix up the two when applying to the penis.

If you apply a pea-sized amount, this is about 0.15 to 0.25 grams.

Nitroglycerin is certainly not for everyone. According to a 2018 research review, taking nitroglycerin-based medications with certain PDE5 inhibitors like Viagra is contraindicated. Using them together can result in a sudden and serious decrease in blood pressure and potentially death.

According to Brito, some drawbacks of topical nitroglycerin include possible transmission to your partner, which can cause them to experience side effects, including low blood pressure. This can lead to headaches and nasal congestion.

There are several treatments available for ED, including:

If you experience difficulty achieving or maintaining an erection, talk with your doctor. Your doctor can help identify underlying causes and help address them to reduce symptoms.

Exploring ED treatments

If you have ED and would like to try nitroglycerin gel, talk with your doctor first. There are many medications that cause negative side effects if you use them with nitroglycerin gel too. While there are quite a few, some of the main ones are sildenafil (Viagra), aspirin, or ergotamine, which treats migraine.

Avoid using nitroglycerin gel if you have health conditions like anemia or hypotension. Using nitroglycerin can make these conditions worse.

Nitroglycerin gel side effects

Nitroglycerin gel can cause unwanted side effects. Examples of these effects include:

  • blurry vision
  • dry mouth
  • feeling faint
  • headache
  • low blood pressure
  • nausea
  • rapid heart rate

You could also experience an allergic reaction where you apply the nitroglycerin. An allergic reaction could include redness, swelling, or itching.

If you experience these symptoms, stop using nitroglycerin gel immediately. Remove any excess and avoid touching the nitroglycerin with your hands to ensure your symptoms don’t get worse.

Seek immediate medical attention if your symptoms don’t improve after a few minutes or you’re having trouble breathing.

Does nitroglycerin work the same as Viagra?

No, nitroglycerin doesn’t work the same as Viagra. Your body breaks nitroglycerin down into nitric oxide. This compound expands the blood vessels to promote more blood flow.

Viagra is a phosphodiesterase inhibitor that works to prevent PDE5, which limits blood flow to the penis. The result of using Viagra can be a stronger erection.

How do you apply nitroglycerin safely?

Topical nitroglycerin can work anywhere that you apply it. That’s why you should wear gloves or another protective covering (like a finger covered in plastic wrap) before putting it on your penis. Squeeze a pea-sized dot on your finger and apply to the head of your penis.

Typically, your body will rapidly absorb the nitroglycerin. If enough time passes after application, the gel shouldn’t affect your partner.

Can I use too much nitroglycerin?

One of the benefits to nitroglycerin gel is that it works faster than ED treatments such as Viagra. However, it also doesn’t last very long in the body — usually only a few minutes. If you keep applying it, it’s possible you could use excessive amounts.

The problem is: Since there isn’t much research on how you can safely use it, it’s difficult to say how much is too much and what the side effects are from overuse. That’s why it’s important to talk with your doctor before applying topical nitroglycerin.

Although some research points to the effectiveness of nitroglycerin gel or cream for improving the symptoms of ED, it’s currently not approved by the FDA as a treatment for ED.

If you have ED or think you may have ED, it’s important to talk with a doctor about any treatment options. They can talk with you about the range of options, including lifestyle modifications, counseling, oral agents, penis pumps, surgery, and implants.