DNP (2,4-Dinitrophenol) as a weight-loss drug

The website that sold an industrial chemical as a diet pill

In the early hours of 12 April 2015, a 21-year-old student named Eloise Parry swallowed eight diet pills. Later that morning she drove herself to hospital, arriving around 10am, because she already knew she was in trouble. She was dead by mid-afternoon. The pills contained 2,4-dinitrophenol, an industrial chemical the United States government had declared “extremely dangerous and not fit for human consumption” seventy-seven years earlier, in 1938. Parry had bought them from a website run by a man in his early thirties operating out of premises in Harrow, northwest London.

Bernard Rebelo ran his business under the domain DrMusclePharmaceuticals.com and the trading handle DrMusclePharma, which the sentencing judge found he used to encourage customers with reckless sales talk when he took part in discussions online. What he sold was, on paper, an industrial chemical; in practice, to the people buying it, a fat-burning supplement — sold with no clinic, no consultation, and no licensed medicine involved. Starting in 2013, he imported 2,4-dinitrophenol in bulk drums from China and packaged it himself, by hand, into gelatin capsules at two strengths, 125mg and 250mg, before shipping them out to customers around the world.

“optimum gold”: mail order, mislabeled, worldwide

There was no clinic, no consultation, no gatekeeper of any kind. Rebelo’s entire distribution channel was his own website and his own packing table. Customers ordered online and received small packages in the post, sometimes labeled with invented product descriptions such as “optimum gold,” the description the sentencing judge found he had given to the batch of DNP he sold Eloise Parry. The sentencing judge made two separate findings about how he presented the business: he pretended to be part of The Supplement Store, a legitimate business that in truth had nothing to do with him, and he lied to CCNow, his financial intermediary, to get that company to accept him on their platform. When his original website looked like it was attracting scrutiny from the authorities in December 2013, he simply moved it to a different host and kept trading. The entire appeal of the arrangement, for a customer, was that it required nothing: no doctor’s note, no age check, no pharmacist asking questions. That absence of friction was also the entire danger of it.

A metabolism-booster that cooks its user from the inside

DNP’s mechanism is not vague in the way most quack remedies are vague; it is real, well understood, and precisely what makes the substance so dangerous. It uncouples oxidative phosphorylation inside mitochondria: protons that would normally drive the enzyme that manufactures ATP instead leak back across the mitochondrial membrane, so the energy that would have been captured as usable cellular fuel is released as heat. Stanford pharmacologist Maurice Tainter and colleagues demonstrated in 1933 that this genuinely raises basal metabolic rate and genuinely produces weight loss; modern toxicological review puts the increase at roughly 11 percent for every 100mg taken. That demonstration is supported by the later toxicological literature. What is also not in dispute is that the same uncoupling reaction has no off switch calibrated to human safety: past a small and unpredictable threshold, body temperature climbs uncontrollably, there is no antidote, and death can follow within hours. The sentencing judge in Rebelo’s case put it plainly, citing the toxicological literature: taking DNP amounts to a game of Russian Roulette, with no way to know in advance whether a given dose will be tolerated or fatal.

Ignore the side effects and adjust the dose

Rebelo sourced the chemical, packaged it, marketed it, and sold it for profit; the sentencing judge found his business methods dishonest and his motive financial gain. When customers reported side effects, the sentencing judge found, Rebelo told them to disregard the symptoms and simply adjust the dose — advice that, given DNP’s pharmacology, pushed distressed customers further toward the substance rather than away from it. He knew the product was dangerous; he said as much himself in some of his own online posts. The Food Standards Agency had issued public warnings about DNP fat-burner capsules in 2003 and again in 2012; he ignored both. He kept trading after Eloise Parry’s death, after Interpol issued an Orange Warning in April 2015 concerning a different customer who had been hospitalized after buying DNP from him, and even after downloads about Parry’s inquest turned up on his own phone — trading continued until his premises were finally searched by environmental health officers in February 2016. Sentencing him, Mrs Justice Whipple placed his conduct in category B for culpability (of the guideline’s four tiers, A being highest), finding that he had shown a blatant disregard for a very high risk of death and had been motivated by financial gain; she found the resulting harm was of the highest order because Eloise Parry had died.

Banned once in 1938; resurged illicitly decades later

DNP had already failed this exact test, in public, eight decades earlier. An epidemic of bilateral cataracts among 1930s dieters, documented in the ophthalmological literature by 1942, and a run of hyperthermic deaths led the newly empowered U.S. Food and Drug Administration to declare the drug “extremely dangerous and not fit for human consumption” in 1938, ending its brief run as a marketed weight-loss drug. It did not go away. Modern toxicological review documents that DNP poisoning and deaths surged again from the early 2000s onward, driven by unregulated internet sales to bodybuilders and dieters. The sentencing judge in Rebelo’s case put the mortality plainly: of those who presented at hospital between 2007 and 2019 with a history of having taken DNP, 18 percent died — a rate she compared to cyanide. Eloise Parry’s death and Bernard Rebelo’s prosecution (a first conviction quashed, a retrial, and a conviction upheld when the Court of Appeal dismissed his appeal on 8 March 2021) is among the best-documented cases in that modern wave, but it was neither the first nor the last. A peer-reviewed case report from 2024 describes another fatal DNP intoxication, in a young bodybuilder who bought the chemical from a contact at his gym, and notes that fatal DNP cases have continued appearing across the English-speaking world, Northern and Eastern Europe, and Italy since 2010. No study has ever established a dose of DNP that reliably separates the promised fat loss from the risk of death. The chemical the FDA moved to stop in 1938 resurged decades later, under different packaging and through a different sales channel: a 2019 federal toxicology profile recorded it was still marketed by unregulated internet sources, a fatal case was reported in the medical literature in 2024, and a 2025 health-policy review reports UK regulators found DNP in diet pills and prohibited DNP-containing products.