All new beverages introduced to the US market MUST comply with FDA labeling and food safety standards.
The United States doesn't have any set, federal laws on what ingredients can be used in a drink. At present, all that consumers can rely on is individual states and manufacturers' best faith efforts, which results in either tragedy (the case tragedy of those who drank Coca-Cola during WWII) or kooky decisions like those of Procter & Gamble - makers of Crystal Light for over 30 years - who reformulated their product to remove aspartame after aspartame was deemed safe.