Three Democratic lawmakers on Thursday sent letters to 14 marketers of high-caffeinated energy drinks requesting data about the products’ ingredients and any company studies showing their risks and benefits to children and young people.

In recent months, the Food and Drug Administration has begun examining the safety of energy drinks following reports of several deaths and numerous injuries potentially associated with the products. The number of annual hospital emergency visits involving the drinks doubled from 2007 to 2011, according to a federal report released last week.

In addition, claims by drink producers that their proprietary “energy” formulations provide consumers with a physical and mental edge are coming under scrutiny. There is little scientific evidence, researchers say, that the drinks provide anything more than a high dose of caffeine similar to that found in a cup of strong coffee.