Manoj Bhargava, the one-time monk turned energy shot entrepreneur, made his debut on the 2012 Forbes World's Billionaires list thanks to 5-Hour Energy, his two-ounce cocktail of caffeine and B vitamins that flies off she shelves at Wal-Marts and bodegas nationwide. In November, the FDA announced it was investigating Bhargava's product in relation to 13 deaths, calling the safety of energy supplements into question. The billionaire took to YouTube in December to defend 5-Hour Energy -- a rare foray into the public eye for the quiet entrepreneur.
(Eric Eggley) More from Forbes
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