The study, which was published in the journal Drug Testing and Analysis and was conducted by Cohen and two colleagues, found the stimulant present in variety of pre workout supplements tested. Cohen and his colleagues chose 14 supplements for the study that listed the ingredient on the label as AMP citrate, 4-amino-2-methylpentant citrate or 4-methyl–2-pentamine citrate.
The supplements were tested in parallel by NSF International and by the Netherland’s National Institute for Public Health and the Environment. Two of the supplements contained no detectable amounts of the stimulant, whereas the other 12 contained it in dosages ranging from 13 mg up to 120 mg per serving.
The supplements come from a variety of manufacturers and are sold online and in brick-and-mortar outlets such as GNC.
In a story reminiscent of the issues surrounding dendrobium, two of the labels imply that DMBA is a derivative of tea. Even if that might be true, it raises the same isses as were raised with dendrobium, namely that the ingedient is present in teh botanical source in such tiny concentrations as to be commercially unviable and that it could never be said to have been present in the past in the food supply as an article of food and therefore at the very least should have a New Dietary Ingredient Notification on file.
Murky botanical origins
“One study in Chinese by Chen and Ou purports to have found DMBA at levels of 0.012 ppm in Pouchung tea as a degradant upon storage; however, an authentic chemical reference standard was not used to confirm the identity or quantity of DMBA in this study.
"Even if DMBA were found at these very low levels, manufacturers would require at least 1000 kg of Pouchung tea to extract 12 mg of DMBA, and humans would not have previously been ex- posed to the high levels of DMBA that we found in dietary supplements,” the authors wrote.
“We are unaware of any scientific evidence that DMBA has ever been extracted from any plant, while synthetic DMBA is easy to synthesize and widely available,” the paper said.
Designer ingredients on shelf
“There are a bunch of concerns with this,” said Cohen, who is a an assistant professor at the Harvard Medical School. “This is representative of a whole genre of supplement chemicals that concocted in a lab and then end up in mainstream supplements. These are designer stimulants that before you would have had to have gotten from some sort of dealer or bought off the Internet as a research chemical.
“The second pattern that worries me is that FDA is doing absolutely nothing to get this off the market. If they think that DMAA is hazardous, even if you are a risk-based organization it makes sense to go after the next DMAA before it causes the bad outcomes that have been linked to DMAA. These are low-hanging fruit. These are companies that clearly should have filed NDIs on these ingredients, and most of the supplements we tested list the ingredient right on the label,” he said.
Byproduct of DSHEA?
Cohen has been a strident critic of the way in which dietary supplements are regulated under DSHEA. In his view it has created a market in which these types of events—new, untested ingredients showing up on the shelf—are almost inevitable. Still, he emphasized he was not trying to tar all supplements with a preworkout brush.
“I’m not lumping all dietary supplements in this. But this does happen in weight loss supplements and in sports supplements,” Cohen said.
Commenting on the paper, Steve Mister, president & CEO of the Council for Responsible Nutrition said: “We agree with the authors of this analysis that DMBA is an illegal dietary ingredient and therefore should not be used in dietary supplements.
“In fact, last month, CRN formally requested that the Food and Drug Administration (FDA) investigate the regulatory status of this ingredient, marketed as Amp or Amp Citrate. If, in fact, this product is an illegal dietary ingredient, FDA has ample authority under the law to take it off the market, and we would support that.”