Nearly a dozen supplements marketed to help consumers lose weight, improve athletic performance and enhance cognitive function are new cause for alarm. Researchers found an amphetamine-like substance known as BMPEA in products containing Acacia rigidula.

This comes two years after health officials warned against BMPEA, the "designer stimulant" that's often labeled as a plant extract.

Assistant professor at Harvard Medical School and dietary supplement expert Dr. Pieter Cohen said the FDA "completely dropped the ball" in their responsibility to prevent the inclusion of dangerous ingredients in supplements.

"There is not a single weight loss supplement on the market that is legal and that has been shown to lead to weight loss in humans," Cohen said Tuesday on "CBS This Morning."

BMPEA has not been tested in humans, but led to increased blood pressure in cats and dogs.

"These are things that are signals that in humans will later turn into heart attacks, strokes and maybe even sudden death," Cohen said.

In response to Cohen's study, the FDA said the following in a statement:

"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."

"I was shocked when I saw this," Cohen said.

The Council for Responsible Nutrition (CRN), a trade association that oversees over 150 companies involved with the supplement industry said they "share the concerns of Dr. Pieter Cohen."

In a statement, CRN president and CEO Steve Mister said "we urge [the] FDA to take immediate enforcement action against these adulterated products containing BMPEA and the companies illegally spiking these products with this synthetic drug."

The FDA discovered BMPEA in supplements in a 2013 study, but according to Cohen, took no appropriate action to remove BMPEA from dietary supplements.

In fact, Cohen noted in his study published in Drug Testing and Analysis: "Since the FDA discovered BMPEA in supplements, the percentage of brands of Acacia rigidula supplements that contain BMPEA has appeared to increase from 42.9 percent in 2012 to 52.4 percent in 2014."

The synthetic component also sparked international concern. Cohen said Health Canada removed supplements with BMPEA from their market and the European Union has also been clear on its stance: "Acacia rigidula is not permitted to be sold until there is additional evidence of safety."

Meanwhile, Cohen said, "The FDA is telling us there's not even a safety concern."

BMPEA is not the only supplement ingredient that raised red flags in the past year.

In February, an investigation led by New York Attorney General Eric Schneiderman found a number of store-brand herbal supplements did not contain any DNA of the plant advertised on the labels.

In October, a study also published in Drug Testing and Analysis revealed 12 supplements for weight loss, workouts and brain enhancement contain DMBA, a chemical cousin of a substance banned by the FDA, DMAA.

Cohen worries that as they have in the past, supplement makers will produce other difficult-to-detect, harmful ingredients.

"The FDA not only has to move against BMPEA, but they need to move against this product to set an example of what are they going to do when other companies are introducing new stimulants," Cohen said.

Until there is more regulation, Cohen advised against taking any supplements with amphetamine-like ingredients.

"One, is that the supplement's not going to work and you're just wasting your money, and the other option is that it's actually working, leading to short-term weight loss, but exposing you to serious long-term risks," Cohen said.

But not everyone in the supplement industry agrees.

Hi-Tech Pharmaceuticals, which makes Black Widow, Fastin-XR, Lipodrene Hardcore, Lipodrene Xtreme, Stimerex-ES and Yellow Scorpion, all of which contain Acacia rigidula, said the following in a statement:

"Hi-Tech has sold over 1 billion doses since 2003 of Acacia rigidula and its alkaloids--including BMPEA-- and have conducted numerous studies of these alkaloids and believe them to be safe and effective when used as directed."

Vitacost, a company that sold its ARO-Vitacost Black Series BURN, a supplement containing BMPEA, said it is suspending online sales of its product until it has more safety information.

"They will not be available for purchase until we can investigate further, and again have full confidence that these products are safe and effective for our customers."

Cohen wasn't impressed by their actions.

"This is way too little too late. We need all these products off store shelves. More importantly, we need the FDA to be enforcing the law," he said.