 -- Dietary supplements labeled to contain a shrub called Acacia rigidula actually contained a speed-like compound called BMPEA instead, according to a new study, prompting Vitamin Shoppe has announced that it will no longer sell products that contain Acacia rigidula, the national vitamin store chain announced Wednesday.

"If these findings are confirmed by the FDA, these products should not be sold as dietary supplements," Vitamin Shoppe said in a press release Wednesday.

The compound, called BMPEA, is a stimulant that was originally synthesized in the 1930s as a replacement for amphetamines. Amphetamines affect the central nervous system and are prescribed to patients with ADHD and are part of the same drug family as speed and crystal meth. But BMPEA is not a regulated drug, has never been studied in humans, and is not derived from the Acacia rigidula plant, Harvard Medical School professor Dr. Pieter Cohen told ABC News, who reached the same conclusion as the FDA in its 2013 report. Cohen and his co-authors published their study this week in the medical journal Drug Testing and Analysis.

They wrote that they tested 21 supplement brands bearing Acacia rigidula on the label and claiming to help with weight loss, athletic performance and cognitive function. They found that 11 of them contained BMPEA.

"There's an unbelievably potent stimulant, a close relative, a brother of amphetamines -- that’s found in multiple different brands of supplements," Cohen, an internist at Cambridge Health Alliance, told ABC News. "But much more alarming than this is that even though the FDA has known about this for the last 2 years, they have done absolutely nothing to remove these supplements from the market."

In animal studies, the BMPEA increased heart rate, elevated blood pressure and crossed the blood-brain barrier, Cohen and his co-authors wrote. Cohen and his team did not test to see whether the supplements contained true Acacia rigidula, which has not been studied in humans either, Cohen said.

According to the study, the Food and Drug Administration has known about BMPEA mislabeling since 2012, finding that 42 percent of 21 supplements claiming to contain Acacia rigidula contained BMPEA, but they did not disclose which brands they studied.

"While the European Food Standards Agency has cautioned against the consumption of Acacia rigidula products, the FDA has been silent," the researchers wrote. The FDA released the following statement in response to the study.

"The FDA's first priority with regard to dietary supplements is ensuring safety. As part of our overall work on detecting and removing adulterated supplements from the market, and ensuring that products are labelled in a manner that is truthful and not misleading, the FDA published research on the occurrence of BMPEA in Acacia rigidula supplements in 2013. While our review of the available information on products containing BMPEA does not identify a specific safety concern at this time, the FDA will consider taking regulatory action, as appropriate, to protect consumers."

Dietary supplements have come under fire in recent months.

In February, New York State Attorney General Eric Schneiderman sent cease and desist letters to GNC, Target, Walgreens and Walmart in February, barring them from selling store-brand supplements in the state. The attorney general's office said it had tested these supplements for plant DNA listed on the bottles, such as echinacea, ginseng and St. John's Wort, as part of an ongoing investigation. The attorney general's office said it found that 79 percent of the products either had none of the plant DNA listed or were contaminated with unlisted ingredients.

"When consumers take an herbal supplement, they should be able to do so with full knowledge of what is in that product and confidence that every precaution was taken to ensure its authenticity and purity," Schneiderman said last week when GNC announced its more stringent testing guidelines.

On April 2, Schneiderman and 14 other attorneys general called on Congress to work with the FDA to inquire into the supplement industry.

Dietary supplements are not subject to the same safety and efficacy testing as drugs. A 1994 law called the Dietary Supplement Health and Education Act made supplement manufacturers responsible for safety and proper labeling -- not the FDA. The FDA does not approve these supplements before they hit shelves, according to the agency's website. Cohen said supplement manufacturers should at least need to prove BMPEA’s basic safety before putting it on store shelves.

"The bar is incredibly low," Cohen said. "It's practically right on the floor."

The Consumer Healthcare Products Association, a trade group that represents dietary supplement manufacturers issued the following statement from its vice president of regulatory and scientific affairs, Barbara Kochanowski:

“Today, millions of Americans use dietary supplements to support their overall health and wellness. CHPA wants to ensure consumers understand the difference between responsible manufacturers of these products and criminals who sell illegal products marketed as supplements. Supplement manufacturers are required to comply with good manufacturing practices, and CHPA members have a solid track record of doing this.

"Consumers must be able to trust that the information they read on the Supplement Facts label and ingredient list is accurate and that the dietary ingredients are safe. This study underscores the need for FDA to use its authority to crack down on rogue manufacturers that 'spike' their products with illegal or undeclared substances.

"CHPA encourages consumers to investigate the source before purchasing supplements and to only buy from legitimate companies with a strong reputation. We also encourage consumers to avoid products with 'too-good-to-be-true' claims."