Researchers recently identified four banned and potentially harmful stimulants in six over-the-counter supplements. The investigators found the four DMAA-like stimulants in weight loss and preworkout products that are currently available online. The researchers published their findings earlier this month in Clinical Toxicology.

A team of researchers from the United States Department of Defense, Harvard Medical School, the National Institute for Public Health and the Environment in the Netherlands (RIVM) and the global public health organization NSF International researched six brands of supplements whose label listed an ingredient that might be an analog of 1,3-DMAA (1,3-dimethylamylamine). Two separate laboratories used ultra-high-performance liquid chromatography mass spectrometry and reference standards to analyze the supplements.

"Consumers need to be careful when taking supplements, especially preworkout and weight-loss products. You can't always trust what's on the label," said co-author of the study Dr. Pieter Cohen in a press release. "These hidden stimulants are drugs, not natural ingredients, and have no place in over-the-counter supplements."

The team found two FDA-banned stimulants and two stimulants not previously described in scientific literature as ingredients in supplements. The two new stimulants were octodrine and 1,4-DMAA.

The two previously-banned stimulants were 1,3-DMAA and 1,3-DMBA (1,3-dimethylbutylamine). 1,3-DMAA narrows arteries and other blood vessels to elevate blood pressure, and it may lead to cardiovascular problems such as arrhythmias, shortness of breath, tightening in the chest and heart attack. Seizures and other neurological and psychological conditions may occur as a result of 1,3-DMAA use.

The researchers also detected octodrine, a stimulant some use to boost performance or increase weight loss, and a newly identified DMAA analog. These compounds were not listed on the labels of six supplements.

Several supplements labeled 1,4-DMAA as if it were an extract or a constituent of Aconitum kusnezoffii, which is a genus of flowering plants used in Chinese medicine to treat cardiac insufficiency, but there is no scientific evidence that 1,4-DMAA has been detected in or extracted from aconitum.

Unscrupulous supplement manufacturers try to disguise ingredients. Aconitum kusnezoffii and 2-aminoisoheptane appear to be the newest cover for banned or unapproved stimulants. While no evidence supports 2-aminoisoheptane as a legitimate plant-based dietary ingredient, the ingredient is increasingly popular in preworkout and weight-loss products.

The study found the following products contained potentially harmful quantities of the listed stimulants:

  • Game Day by MAN Sports: Octodrine
  • Infrared by Gold Star: 1,3-DMAA
  • 2-aminoisoheptane by Chaos and Pain: 1,4-DMAA
  • Simply Skinny Pollen by Bee Fit with Trish: 1,3-DMAA and 1,4-DMAA
  • Cannibal Ferox AMPED by Chaos and Pain: 1,3-DMBA
  • Triple X by Gold Star: 1,4-DMAA

The stimulants found in these supplements are potentially harmful, causing hemorrhagic strokes, adverse cardiac events or sudden death. Adverse effects from dietary supplements send thousands to the emergency department each year.

The unapproved stimulants may be pharmacologically similar to ephedrine, banned by the FDA in 2004 due to serious adverse effects and deaths. In the years since, scientists at NSF International have identified several unapproved and potentially dangerous stimulants in dietary supplements.

Based on their findings, the researchers encourage consumers to avoid products whose labels list 2-aminoisoheptane or Aconitum kusnezoffii as ingredients.

"Most supplement manufacturers are committed to ensuring quality and safety, but there are a few irresponsible and unscrupulous companies out there, and their actions are putting consumers at risk," said another co-author of the study, John Travis, Senior Research Scientist at NSF International.