Last week, Chad Johnson, a former American football wide receiver, shared a secret to his success. He revealed that he used to take Viagra before every game.

The 42-year-old tweeted, “I took viagra before every game & people thought they’d stop me, if my stat line was bad i wasn’t covered, the pass was just incomplete.”

Did the little blue pill really give Johnson an edge on the field? Did he actually take the blockbuster erectile dysfunction (ED) drug to boost his performance?

Well, before knowing that, it is important to understand what Viagra does to the human body. Actively composed of sildenafil citrate, Viagra works as a vasodilator, meaning it dilates the blood vessels in the body to increase blood flow.

Studies have found that Viagra does help men who have ED because it increases blood supply to the penile organ to cause an erection. However, there is little evidence of Viagra benefiting athletes. Many believe that the drug sildenafil could assist athletes on the field.

In 2008, Roger Clemens, former professional baseball pitcher, routinely took Viagra before games while playing for Yankees.

In the infamous BALCO scandal, Victor Conte said, “All my athletes take it,” calling it one of the most important performance-enhancing drugs available. He said sildenafil was not banned by any major sporting league at the time.

There is evidence that Conte was right about using Viagra to boots athletic performance.

A 2006 study found that sildenafil vastly improved the aerobic output of athletes when their body was starved of oxygen. The study researchers found that performance was significantly increased among cyclists who took sildenafil at altitude than those who did not take the drug.

However, the study showed that Viagra had little to no effect when used in environments where athletes had access to normal oxygen levels.

The findings make it difficult to understand whether the drug really has an effect in an NFL environment. However, it is clear that many football players are subjected to oxygen deprivation during games so there is supplemental oxygen available on the field. Keeping those findings in mind, Johnson might have had an edge – thanks to Viagra.