His family and friends could hardly believe Alladin, a fitness enthusiast, would actually have taken the pill, which is popular among bodybuilders, but can be deadly. And he wasn’t the only victim in England in 2013. Two other students died after taking similarly hazardous weight loss pills.

Despite widespread warnings, it has been impossible to ban sales of controversial diet pills so far. In Germany, as elsewhere, ordering these products online is no problem. Maria Kristina Parr, a professor of pharmaceutical chemistry at the Institute of Pharmacy at Freie Universität Berlin, has done so with her team for research purposes in recent years. “In cooperation with the German Customs Criminological Office (ZKA), in Cologne, and with the German Sport University Cologne, we tried to trace two things. How do you get these kinds of diet products in Germany? And what exactly do they contain?” she explains.

Stimulants, appetite suppressants, diet pills, nutritional supplements, designer drugs, doping – Parr and her colleagues often deal with substances from this area of pharmacy. The working group focuses especially on analyzing medications and biological samples.

The researchers use various techniques to trace how the body breaks down certain medications, for example. Or specific active ingredients that can be used for doping. For example, her research group, with financial support from the World Anti-Doping Agency, is working on a test that aims to show whether an athlete has taken the drug clenbuterol to build muscle and enhance performance.

But many of the substances on the anti-doping agency’s index are relevant to more than just top athletes. Stimulants, for example, are of interest to bodybuilders as well – and to people who want to lose weight.

Stimulants such as amphetamines and ephedrine, which is commonly found in cough syrups, place the body on high alert. They act much like the body’s natural hormones adrenaline and norepinephrine, Parr explains – the hormones that trigger the human body’s “fight or flight” response, which has been with us throughout or evolution, allowing us to shift from a relaxed state to high alert in record time at moments of heightened danger. Breathing accelerates and fatigue vanishes as if by magic; the heart beats faster, and the body activates a huge amount of energy. “In particular, quickly providing energy by mobilizing fat reserves is the reason that we see traditional stimulants being used over and over for weight loss as well,” the scientist says.

Some of the products the researchers ordered online were found to contain methylhexanamine. This substance, which until a while back was also found in decongestant nasal sprays, is also on the anti-doping agency’s list of banned substances due to its stimulant effect.

Pharmaceutical preparations containing methylhexanamine raise the user’s blood pressure and cause shortness of breath. They are also suspected of causing cerebral hemorrhage and liver damage. After a series of deaths linked to taking these products, approval for medications containing methylhexanamine was revoked in Germany.

Even more dangerous than methylhexanamine is the second active ingredient the researchers found in their analysis – 2,4-Dinitrophenol, or DNP. “DNP works based on a completely different principle,” Parr says. It affects a certain part of the catabolism, the type of metabolism concerned with energy: the electron transport chain. This is where adenosine triphosphate (ATP), the “fuel” for muscle cells, is generated. To do this, the body relies on various sources, including its fat reserves. DNP disrupts this process, halting production of ATP. The only thing produced in this case is heat.

Shortness of Breath and Cerebral Hemorrhage as Side Effects

“The result is that the body burns its energy reserves like a poorly functioning furnace: Instead of heating the room, the heat is lost through the chimney,” Parr explains. This rapid burning of fat has at least two dangerous side effects. First, the body no longer receives any energy. And second, the body temperature rises to risky levels. “The temperature increase is comparable to an extreme fever, and it is potentially deadly,” the scientist says, explaining that DNP can cause shortness of breath, multiple organ failure, and even death.

DNP is not a new active ingredient, and its risks and side effects have been well known for around a hundred years now. Back then, the substance was used primarily in the armaments industry, where it was used together with trinitrotoluene, or TNT, to produce artillery grenades. Workers who came into contact with DNP in factories not only complained of vertigo, but also reported extreme weight loss. In the United States, this led to DNP being used in a weight loss product in the 1930s. But not long afterward, in 1938, the American authorities banned DNP again. “Even back then, they saw that it is hardly possible to use this active ingredient in a controlled fashion, and that the side effects are simply too serious,” Parr says.

Nowadays, products containing DNP are sold on the Internet, often under various names: “Yellow Fat Burner” and “DNP Burn” are just two current names. Listings of the substances and warning notices, however, were missing from all of the products the scientists ordered for their spot check.

“It was scary to see how easy it is to buy these products on the Internet,” Parr says. And the analysis also clearly showed one more thing: “The composition and quality of products bought online fluctuates widely, so the situation with these kinds of diet and weight loss preparations is comparable to the black market for drugs.”