Fans of Monster Energy, the popular high-caffeine energy drink, may not notice the change: Its ingredients will be the same and its familiar label bearing a green, clawlike monogram will change only slightly.
But the drink's maker has decided after a decade of selling it as a dietary supplement to market it as a beverage, a switch that will bring significant changes in how it is regulated.
Among them: Monster Beverage, the nation's biggest seller of energy drinks, will no longer be required to tell federal regulators about reports potentially linking its products to deaths and injuries.
The company's move, which follows a similar regulatory makeover by another brand, Rockstar Energy, comes amid intensifying scrutiny of energy drink safety.
On Tuesday, a group of 18 doctors and researchers sent a letter to the Food and Drug Administration urging it to take action to protect adolescents and children from the possible risks of high caffeine consumption.
In their letter to FDA Commissioner Dr. Margaret A. Hamburg, the group argued that energy drink makers had failed to meet the regulatory burden placed on them to show that the ingredients in their beverages were safe, specifically where children, adolescents and young adults are concerned. The group urged the agency to restrict caffeine content in the products.
Monster Beverage's new cans will also disclose caffeine content for the first time. A 16-ounce can of Monster's most popular energy drinks will contain 140 to 160 milligrams of caffeine, compared with about 330 milligrams in a 16-ounce cup of Starbucks coffee.
The company is fighting back against critics on several fronts. This month, it held a news conference to dispute accusations in a lawsuit that the death of a 14-year-old Maryland girl who had consumed two 24-ounce cans of Monster Energy was linked to high caffeine levels in Monster Energy.
Separately, it threatened to sue a nutritionist who publishes a newsletter for elementary schools for statements that it said were defamatory.
The changes by Monster and Rockstar demonstrate the degree to which energy drink manufacturers can decide which rules to follow.
"We don't have energy drinks defined by any regulation," Daniel Fabricant, director of the FDA's dietary supplement division, acknowledged in an interview in October.
For a decade, Monster sold its products as dietary supplements, apparently as part of a strategy to convince consumers that they were different from beverages. But the company, like its competitors, has run into a slew of bad news, including the disclosure in October that the FDA had received reports in recent years that linked its drinks to deaths and injuries.
Since then, the FDA has received three more death reports and 14 injury reports that cite Monster energy drinks, FDA spokeswoman Tamara Ward said in an email. In recent months, the agency has also received reports about other energy products; since October, for example, it has received 38 reports that cite the popular energy "shot" 5-Hour Energy, including five involving a death.
The mention of a product in an incident report filed with the FDA does not mean the product played a role in a death or injury. Monster Beverage and the maker of 5-Hour Energy have insisted that their products are safe.
A spokesman for Monster, Michael Sitrick, said the company had decided to market its products as beverages for several reasons. One was to stop what he described as "misguided criticism" that the company was selling its energy drinks as dietary supplements because of the belief that such products were more lightly regulated than beverages.
Another consideration, he said, was that consumers can use government-subsidized food stamps to buy beverages.
An executive vice president at Rockstar, Joseph Cannata, said the firm made the change because consumers found food labels easier to read. In January, all production of Rockstar energy drinks switched to those labels.
A lawyer who represents supplement makers, Justin J. Prochnow, said firms such as Monster and Rockstar might have had another incentive. Over the past two years, the FDA has intensified its scrutiny of the supplement industry's manufacturing practices, driving up production costs.
As beverage producers, Monster and Rockstar will face some reporting mandates, including some that are stiffer than the mandates for supplement makers.
Such companies are required to notify the government when they think a product could cause injury, a rule intended mainly to limit the distribution of tainted food. In addition, they must maintain scientific data supporting the safety of any ingredients they use that are not already cleared by the government.