Viagra Before a Workout? Yup, It’s a Thing.

In theory, it makes sense. But in practice? Not so much.

• Viagra is an erectile dysfunction drug that increases blood flow to the penis
• Since Viagra was approved by the Food and Drug Administration (FDA) in 1998, athletes and bodybuilders have been using it for another purpose: as a pre-workout supplement

Last year, Sam*, 27, started taking anabolic steroids. “I always wanted to be big and strong,” he told MensHealth.com, “At some point I realized my goals were unattainable naturally, so I hopped on the juice.” He had heard that steroid use could potentially lead to erectile dysfunction, so he started taking 10mg a day of the erectile dysfunction drug Cialis.

Then Sam started spending a lot of time on Reddit. He quickly discovered another potential benefit for Cialis. “I saw that people were taking it before their workouts,” he said. “So I changed the timing of my doses to about an hour prior to training.”

To hear Sam tell it, he noticed the difference right away. “I noticed increased vascularity and good pumps,” he said. “Plus, it seems to help reduce cramping/debilitating pumps from oral steroids. I have better erection quality as well, which is obviously pretty great.” Though he eventually dropped to 5mg per day to improve nasal congestion (a common side effect of erectile dysfunction drugs), he continues to take it before his workouts.

Every few months, it seems like there’s a new “get ripped quick” scheme promising mad gains to muscle-hungry guys aching for tight bods. One popular theory that has circulated bodybuilding forums is the Viagra workout, or the idea that taking erectile dysfunction drugs can boost your gains at the gym. The theory pops up every so often in bodybuilding threads on Reddit, but it’s also gained some traction in the professional sports world: Seattle Seahawks wide receiver Brandon Marshall has said that he’s heard of NFL players taking Viagra to boost their performance on the field.

In theory, at least, the idea makes some sense. Viagra, a.k.a. sildenafil, was initially developed as a treatment for hypertension and angina pectoris, a type of chest pain caused by reduced blood flow to the heart. It works by opening up the blood vessels, which allows blood to flow more freely to, um, all organs. (We reached out to Pfizer, the company that manufactures Viagra, for comment and will update if we hear back.)

“Sildenafil increases blood flow to the penis and surrounding muscles, which translates into a nice strong erection,” says urologist and assistant professor at the UCF College of Medicine, Jamin Brahmbhatt, MD. “This increased blood flow is what some athletes hope to have to get them to build up their bodies faster.” Viagra also contains nitric oxide, a key ingredient in many legal bodybuilding supplements (though it’s worth noting that the benefits of nitric oxide for building muscle are pretty unclear).

“Side effects include low blood pressure and priapism, or an erection lasting more than 4 hours.”

There’s a small amount of research to support these claims. A few studies have suggested that taking sildenafil can benefit athletes competing at high altitudes, such as cyclists or long-distance runners, by delivering more oxygen to their muscles. Additionally, a 2013 study in the journal of Clinical and Translational Science suggested that sildenafil could increase muscle protein synthesis and reduce muscle fatigue, concluding that it may “represent a potential pharmacologic strategy to improve skeletal muscle function.”

But Brahmbhatt says there were serious limitations to this study. “The study found some potential benefit in gaining muscle mass if you took low doses of Viagra,” continues Dr. Brahmbhatt, “but that study was flawed by its small size. This is a great example of how you should not get caught up in the hype of one study.”

Overall, Brahmbhatt says that Viagra and a workout aren’t a good mix. “There are several side effects to Viagra,” he says. “The two biggest ones I tell patients are that it can decrease your blood pressure and priapism (an erection lasting more than 4 hours).” Other side effects include “headaches, abnormal heart rates, and even heart attack from decreased blood flow/pressure.”

That doesn’t mean, however, that guys are going to stop taking Viagra without a prescription anytime soon. Prices for the drug have never been lower, and millennial men are increasingly taking Viagra without a prescription, even if they don’t necessarily struggle with erectile dysfunction. Websites like BlueChew have popped up to meet the increasing demand, offering sildenafil and tadanefil at a quarter of the price of name-brand Viagra.

In a statement to MensHealth.com, a spokesperson for Blue Chew was reluctant to suggest that Viagra should be used for any reason other than to enhance sexual performance. “While Sildenafil likely does have positive affects outside of ED, like for working out, BlueChew does not want to imply that they can prescribe for those reasons,” a spokesperson for the company said.

Regardless of the effectiveness of Viagra as a pre-workout supplement (or lack thereof), for his part, Sam isn’t sure it was a good idea to take it in the first place. In fact, he says it probably made his struggles with his own body worse. “I’m probably where I wanted to be originally. But. the lengths I’m willing to go to in order to get bigger are ever-expanding,” he says.

*Last names have been withheld to allow subjects to speak freely on private matters.