(CNN) -- Craze, a sports supplement marketed to bodybuilders, contains a chemical compound similar to the illegal drug methamphetamine, according to a study published in the peer-reviewed Drug Testing and Analysis journal. The substance, called N,alpha-diethylphenylethylamine or N,a-DEPEA, has never been studied in humans, according to Dr. Pieter Cohen, an assistant professor of medicine at Harvard Medical School and lead author of the study.
Scientists tested three Craze samples from three different suppliers, according to the study. They found N,a-DEPEA in all three - about 20 to 35 milligrams of the drug in a serving size of the supplement. These dosages suggest it was "not a minor contaminant resulting from the manufacturing process," the study authors wrote.
N,a-DEPEA is a methamphetamine analog, Cohen said, or a "cousin" to meth. Scientists first discovered the new drug approximately three years ago in South Korea.
"Criminal-chemists start with a known drug - in this case methamphetamine, then in their factor they start making little changes to it," Cohen explained in an e-mail. "Here, they pop a few extra carbon and hydrogen molecules onto it. But the main structure/backbone/skeleton of the drug remains the same."
Craze labels list a different chemical, N,N-DEPEA, as an ingredient, Cohen said, but researchers did not find that substance in the supplement. He said it was unlikely that Craze's manufacturer, Driven Sports, was directly responsible for altering the chemical structure of the drug. The company may have purchased the substance in bulk from a distributor that claimed it was all natural, Cohen said.
Craze was given BodyBuilding.com's New Supplement of the Year award in 2012.
"Craze is a legal supplement that provides people with a tool to enhance their workouts, by combining natural extracts to increase their energy," Driven Sports said in a statement. "Craze conforms to all U.S. federal regulatory requirements and is proven safe when used as directed... Driven Sports has commissioned extensive testing of Craze from a reputable, independent laboratory, which conclusively establishes that the product does not contain any illegal stimulants."
One of the samples used in the study was sent to the Food and Drug Administration last year; the study authors' conclusions were sent to the FDA in May. While the FDA is in charge of regulating dietary supplements, manufacturers and distributors are not required to get FDA approval before selling their products.
NSF International, a public health organization involved in the study, also found N,a-DEPEA in a different manufacturer's supplement, Cohen said. Gaspari Nutrition's Detonate seems to have been removed from the company's website and is no longer available on Amazon or other sellers' sites.
This isn't the first time Driven Sports' products have come under scrutiny. In July, USA Today published an investigative piece on supplement designer Matt Cahill, "a convicted felon who has a history of selling risky dietary supplements, including products with ingredients linked to severe liver injury and at least one death," the newspaper says.