Losing weight is hard. Many people have tried it; many do not succeed. In 2016, 49% of all Americans tried a diet but, by some estimates, fewer than half of people who tried succeeded.

According to the NIH, about 15% of Americans have tried weight loss supplements. Supplements aren’t held to the same standards as medications in terms of regulatory oversight, which means consumers aren’t always getting what’s promised on the label. Pieter Cohen, MD, an associate professor of Medicine at Cambridge Health Alliance in Somerville, Mass. has been interested for a long time in the contents of the supplements we take. Dr. Cohen has been a vocal critic of how dietary supplements are regulated.

Checking the label -- and the contents

In a paper published March 23 in Clinical Toxicology , Dr. Cohen and his research team looked for deterenol, a beta-agonist that has not been approved for use in humans. A beta-agonist is a class of medications that relaxes airway muscles, thereby helping with breathing.

Using Google to locate supplements that advertised deterenol, Dr. Cohen found 17 supplements that advertised deterenol in them. Dr. Cohen found deterenol in 13 of the 17 brands he tested. He considers this odd because all 17 listed deterenol as an ingredient. "It's surprising that a prohibited stimulant is listed on the label but not found in the product," said Dr. Cohen, "It's hard to divine what level of manufacturing dysfunction could lead to that outcome."

Deterenol wasn’t the only compound found in these pills. And that is part of why they might be so dangerous. “ … We found deterenol mixed with other experimental stimulants. We have no study to predict at what dose a combination of these prohibited stimulants would cause serious health effects,” said Dr. Cohen. The researchers also found 9 other experimental stimulants and 8 combinations of prohibited stimulants.

Deterenol came to Dr. Cohen’s attention when his colleague, Bastiaan Venhuis, followed up on 26 cases of deterenol toxicity reported to Dutch authorities. “When our colleagues in Europe investigated the cause of several cases of serious adverse events linked to supplements - they discovered deterenol in the supplements combined with other ingredients,” Dr. Cohen explained, “We wanted to know if deterenol might also be available in supplements sold in the US.”

In the Netherlands, the 26 instances of complications came from Dexaprine and Dexaprine XR, supplements aimed at athletes and others looking to lose weight. People who took these supplements containing deterenol experienced a fast heart rate, sweating, chest pain and heart palpitations. There was one reported case of cardiac arrest. Upon investigation, the researchers found deterenol, along with several other compounds, in the supplements. They were only able to test 4 of the pills, as the other 22 complainants had discarded their pills.

According to Dr. Cohen, there are no studies that show deterenol leads to weight loss.

Seized for your safety

Blue Ice, made by EPG, was one weight loss supplement that Dr. Cohen analyzed. He found that it contained about 15mg of deterenol per serving.

One consumer reviewing the pills wrote, “This stuff scared the heck out of me. I started breathing fast and got very warm and felt a sudden mood change! I didn’t know if I should drive to the hospital or not.” Even so, this person persevered and claimed to have lost 6 pounds.

Consumers should not confuse these supplements, which range from "fat burners" to pre-workout drinks and weight loss pills, with prescription weight-loss pills. "To be approved as a prescription weight-loss drug in the US you need to convince the FDA through large randomized controlled trials that it's effective and safe for weight loss," said Dr. Cohen.

While all drugs have side effects, he explained, an FDA-approved medication must list all side effects on the packaging. Supplements aren’t required to undergo clinical trials so the agency does not have data on side effects before the drugs go to market.

The FDA regulates the ingredients in the supplement and requires that the manufacturers ensure their products’ safety. It also requires that the labeling be accurate.

But, it only reviews supplements after they’ve made it to market. The FDA is “... responsible for taking action against any adulterated or misbranded dietary supplement product after it reaches the market.” So consumers face a window of time between when an adulterated or misbranded product is available for purchase and any recall action.

  • The FDA, which records show for the last two years or so spent much of its investigative time on supplements containing non-labeled erectile dysfunction medicines, have listed most, if not all, of the Cohen study chemicals on its Dietary Supplement Ingredient Advisory List.
  • In 2013 the FDA released a statement about dimethylamylamine, DMAA, announcing that it was “ using all available tools at its disposal” to stop dietary supplements containing DMAA. Two of the supplements Dr. Cohen tested in the current study contained DMAA. Without testing, the FDA considers products containing DMBA “adulterated.”
  • Although not banned or considered an adulterant, BMPEA is not considered a “dietary ingredient” by the agency. Two of the Cohen supplements contain BMPEA.
  • Higenamine, chemically akin to amphetamine, is known by at least 15 other names.
  • Oxilofrine, found in four supplements, and octodrine, found in three, are also not considered supplements. Oxilofrine, a stimulant, “does not meet the statutory definition of a dietary ingredient” and octodrine is considered an adulterant.
  • Another chemical found was phenpromethamine. In highly sensitive testing of its molecular weight it resembles methamphetamine and amphetamine. Once marketed as a nasal inhaler called Vonedrine , the manufacturer took Vonedrine off the market in 1960 and it lost FDA approval in 1971.

If some of these chemicals are known to be dangerous, let alone not tested or approved for use in humans, why are they in weight loss supplements? Part of it comes down to the FDA’s regulatory structure, which Dr. Cohen termed as flawed.

Medicine vs supplements

FDA-approved prescription medicines and over-the-counter treatments can only contain claims if the claims are backed with research. To get in front of a consumer, the manufacturer needs to have data to prove that the product can do what it is purporting to do. With supplements, the FDA will review a supplement if it has a new ingredient that hasn’t been sold in a supplement before October 1994. This is why several of the compounds were considered adulterants; their manufacturers had not submitted the compounds as new ingredients to the FDA.

Other institutions have banned these stimulants. For example, t he World Anti-Doping Agency has outlawed most of them. The Department of Defense has too; it f orbids its personnel from taking any dietary supplements containing certain ingredients meant to stimulate weight loss and enhance moods.

Medical Daily reached out to several companies whose products were included in Dr. Cohen’s study; none responded with comment.

The take home

Consumers can always look up ingredients on the FDA’s website. But bear in mind that supplement manufacturers sometimes lie. According to the NIH, “ What’s on the label may not be what’s in the product.” Again, consumers can also check for recalled or tainted supplements before buying.

The NIH warned that a manufacturer’s use of the words standardized, certified or verified does not guarantee the product’s quality or consistency.

Dr. Cohen believes that under current regulations, consumers are in the dark regarding a supplement’s ingredients. “At present, there's no way to know if sports or weight loss supplements contain prohibited ingredients,” he said, “Until the laws can be reformed, my advice is to avoid all supplements sold as pre-workout or weight loss supplements.”

Sabrina Emms is a science journalist. She got her start as an intern at a health and science podcast out of Philadelphia public radio. Before that she worked as a researcher, looking at the way bones are formed.