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NEW YORK (Reuters Health) – At least a dozen dietary supplements available in the U.S. contain a potentially-dangerous synthetic stimulant that has never been tested on humans, says a new study.
The inclusion of the stimulant known as DMBA in dietary supplements has researchers and an industry group calling on the U.S. Food and Drug Administration (FDA) to take action.
“All the FDA would need to do is look at the labels of the products that we studied and they could immediately see . . . that this is not an ingredient that was previously in supplements,” the study's lead author Pieter Cohen told Reuters Health.
Cohen, from Harvard Medical School and the Cambridge Health Alliance in Massachusetts, said he and his colleagues discovered the synthetic stimulant listed on dietary supplement ingredient labels under a variety of names.
They searched the Internet for dietary supplements that advertised ingredients with names similar to DMBA's full chemical name, 2-amino-4-methylpentane or 2-amino-4-methylpentanamine.
The searched terms included AMP Citrate, 4-amino-2-methylpentane citrate, 4-amino-2-pentanamine, Pentergy and 4-AMP. They bought each of the 14 products that met their criteria and sent one bottle of each to two separate labs for analysis.
The researchers found that 12 of the supplement products contained DMBA, which stands for 1,3-dimethylbutylamine. The synthetic stimulant is similar to a compound known as DMAA, which the FDA said can lead to heart attacks. The agency told manufacturers in 2012 to stop selling DMAA-containing supplements.
“This is probably just a fraction of the supplements in the U.S. that contain this new designer stimulant,” said Cohen, because the manufacturers advertised it on the label.
He said manufacturers might include DMBA because it may act like the banned DMAA at higher doses. DMAA was marketed as a body building, athletic and weight-loss enhancer. The FDA received dozens of illness and death reports tied to DMAA-containing supplements.
The 14 products tested for DMBA in the new study were mostly marketed as sports or weight loss supplements or brain enhancers, Cohen's team reported October 8 online in Drug Testing and Analysis.
In September, the Council for Responsible Nutrition (CRN), which is the trade association representing the dietary supplement industry, sent a letter to the FDA flagging the marketing of “AMP Citrate” as the "next DMAA" or as a "DMAA alternative."
“CRN is concerned about the potential dangers to consumers who may be using possible unsafe supplements containing Amp Citrate," the letter continued. It also noted that FDA does not appear to have received the proper paperwork, known as an NDI, for the substance.
“We have not heard anything back from the agency,” said Steve Mister, president and CEO of CRN.
In a statement to Reuters Health, the FDA said it is aware of the concerns regarding DMBA and AMP Citrate. The agency will consider taking regulatory action to protect consumers, the statement continued.
“Manufacturers of dietary supplements are responsible for ensuring that their supplements are safe and, where required, must submit a new dietary ingredient notification before marketing,” the FDA said in its statement. “Our pre-market authority for dietary supplements is limited to the requirement for NDI notification. We take this matter seriously and are considering the next steps.”
GNC, a global supplier of health and wellness products, reportedly removed some products containing DMBA from its website, according to a report from USA TODAY.
“GNC does not comment on industry studies nor do we typically comment on product selection or availability,” GNC told Reuters Health in a statement.
Mister said retailers have a responsibility for what they put on their shelves. He added that the FDA already has the authority and regulatory power to immediately act on these supplements.
People with supplements that use or include the name AMP on their labels should return the products to where they were originally purchased, Cohen said.
“Right now we have to avoid these pre-workout supplements and avoid these weight-loss supplements altogether until the FDA can better regulate it,” he added.
Mister also said consumers should always be wary of supplements that claim to contain “barely legal” compounds or elements that will soon be banned.
“The vast majority of the supplements on the market are not going to contain something like this,” he said. “This is a small category in the body building and weight-loss area.”
Drug Testing Analysis 2014.
(This story has been refiled to add dropped letter to Pieter in paragraph 3)