New York's attorney general has issued subpoenas to PepsiCo, Monster Beverage and Living Essentials requesting information on the marketing of their energy drink brands, the Wall Street Journal has reported.

The subpoenas, issued in July, have been issued to see if the companies oversold the effects of certain ingredients while understating the role of caffeine, which is believed to be the main active ingredient, the Journal said, citing a person familiar with the matter. PepsiCo sells energy drink AMP, while Living Essentials owns the 5-Hour Energy brand.

Monster Beverage's namesake brand is the top-selling energy drink in the US.

In a July bond-offering memorandum, Living Essentials said a state attorney had requested documents about its products and marketing.

Today, a spokesperson for 5-Hour Energy told just-drinks it had nothing to add to the memorandum.

“We will appropriately disclose any new, material, information,” the spokesperson said.

PepsiCo declined to comment, while Monster could not be reached.

Earlier this month, Monster confirmed it had received a subpoena from a US state attorney general concerning the "advertising, marketing, promotion, ingredients, usage and sale of its Monster Energy brand of energy drinks".

New York City mayor Michael Bloomberg has recently set drinks companies in his sights with a proposed ban on large-size full-sugar drinks sold in the city's restaurants, stadiums and cinemas.

Last week, one of the leading opponents of the ban said it expected the proposal to pass New York's health board next month.