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Muscles in a Vial: Can a Single Shot Turn You Into Captain America?

Thor is a god, the Green Lantern linked up with some aliens, and the X-Men got their powers from genetic mutations. But Captain America, the latest superhero to attempt box-office domination this summer, owes his abilities to science. Through an experiment, the skinny weakling Steve Rogers becomes a super-soldier who pushes the limits of human performance.

In the movie, the so-called "rebirth" takes place inside a heavily wired and illuminated pod. The pod pumps him with drugs, lights flash, electronics spark, and, in a matter of minutes, the previously 90-pound Rogers emerges looking like a cross between a linebacker and an Abercrombie and Fitch model.

Impossible, right?

The general concept, if not the incredibly fast transformation, is actually conceivable, according to biologist Brian Kaspar of the Research Institute at Nationwide Children's Hospital in Columbus, Ohio. Kaspar and his group have been developing a treatment that increases muscle mass and strength with a single shot. Yet they are not building super-soldiers. They're hoping to help people with degenerative muscle diseases — an injection of the drug could make it easier for those people to walk.

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The drug works by targeting myostatin, a gene that halts muscle growth. "If you eliminate the myostatin, you release the brakes, so to say, and muscles become bigger," he says. Kaspar's technique relies on a protein called follistatin to do this job. His group takes bits of DNA that have the manufacturing instructions for the protein, slips them inside viruses gutted of everything but their outer coatings, then injects these stripped shells into muscle. [Why Do Carbs Imrove a Marathoner's Performance?]

Once the viruses slip through the cell walls, the DNA fragments use the cells' machinery to start cranking out follistatin proteins. The follistatin shuts off myostatin activity, and muscles grow. It takes only one shot, Kaspar explains, and in animal testing, the results aren't Captain America fast, but they're quick from a clinical perspective. "Within six weeks you can see that the muscles are bigger," he says.

The compound has proven to be safe and effective in animal testing, and it won't produce accidental Schwarzeneggers. "There is a maximal muscle size," he says. "There is a degree of regulation."

Kaspar and his group are now applying to the FDA to test the drug in humans. Since their goal is to help people suffering from debilitating muscle diseases, aspiring Captain Americas and "Jersey Shore" castoffs won't be getting shots of their own. "The idea of it getting into the hands of the general population is very hard to imagine," he says.

As for the military, the Army's super-soldier program doesn't appear to have this kind of performance-enhancing drug at its disposal, but maybe, just maybe, somewhere deep in a secret government lab.

Gregory Mone is the author of the novel FISH.

This story was provided by Life's Little Mysteries, a sister site to LiveScience. Follow Life's Little Mysteries on Twitter @llmysteries, then join us on Facebook.