Marketers of energy drinks are preparing to defend themselves against potential restrictive regulations and negative brand perception amid investigations into the safety of their products and alleged links to nearly 20 deaths. Energy-shot leader 5-Hour Energy has boosted ad spending and has included discussions of safety in online videos, while energy-drink maker Monster has pulled back on ads. "It's been a high-growth, high-profit category, and I think the threat of potential new regulations certainly creates a question mark," said Beverage Digest's John Sicher.