Recently, the New York Times published a sobering story on the alumni of the 2009 season of The Biggest Loser. A study had shown that almost all of those who had publicly lost hundreds of pounds on the show’s punishing diet and exercise regime had gained nearly all of it back, unless they made staying slim the focus of every waking moment. Their resting metabolism, it turned out, had been broken down to a murmur by the weight loss. We’ve long known that the body doesn’t want to lose weight, to give up its “stubborn” extra pounds—but the study showed that it puts up much more of a fight than anyone thought, refusing to recognize our cultural conviction that skinniness is inarguably superior, physically and morally. As long as there have been diets, there have been dreams of cheating them with science: a pill that would to reduce the appetite or burn away weight.

In the summer of 1933, three Stanford scientists described an astonishing experiment they had performed that seemed to promise magic. In the Journal of the American Medical Association, they reported on the effects of a chemical called “2,4 Dinitrophenol” or alpha-dinitrophenol (DNP), which sped up the body’s metabolism by an astonishing 30 to 50 percent in all nine of their test subjects, causing them to drop around two pounds a week without a pang of hunger. In the overcrowded, over-promising, and over-leveraged field of diet supplements and slimming snake oils it was something new, and it would prove to be both a miracle and menace. Enterprising drug manufacturers seized on the report and followed its template to concoct their own miracle weight-loss pills. “Redusols,” a typical brand, cost $3 for a 30-day supply (about $55 today), and the company spent thousands of dollars advertising it in newspapers and magazines.

Journalists also seized on the story and spun its implications to improbable ends. TIME magazine described the drug as “a vigorous prod for sluggards and a subtle weapon for murderers.” In an article called the “The Skin Food Skin Game,” on the regulations around diet and beauty products, New Republic editors imagined the “economic revolution” that would follow if the drug were proven safe. The summer of 1933 was a nervous time—FDR had just recently put in place the apparatus of the New Deal—and another market crash might come from anywhere. “Manufacturers of rowing machines and other gymnasium apparatus will find their sales enormously curtailed,” the magazine suggested. “Other anti-fat remedies will perhaps be driven off the market. Certain health resorts will no longer be patronized, and manufacturers of clothing, furniture and other products for the excessively stout will see their patronage dwindle.” A magic bullet could have all kinds of side effects.

DNP had been familiar as an industrial chemical for a long time—it was used in fabric dyes, wood preservatives, photographic film developers, pesticides, and most usefully of all, as an explosive. Its fat-burning capacities had first been noted among French munitions workers during World War I, who absorbed the yellowish, powdery substance through their skin and lungs. It caused them sweat like crazy, and occasionally, they died—several pounds lighter. On a molecular level, DNP is a natural explosive: It blows up the pathways by which cells convert fat and carbohydrates into useful energy and instead generates excess heat, setting tiny internal fires that can raise the body’s temperature to lethal levels. Side effects include cataracts, skin lesions, liver and heart problems, and an eerie yellow tinge to the eyes. Once it hit the market, people bought it by the truckload.

The 1930s were a heyday of self-help and self-reliance, as Americans searched for ways to fortify themselves against the uncertainties of the Depression. Fad diets offered the illusion of control over one’s circumstances: The Hay diet insisted on sorting and separating foods into acid and alkaline groups; the grapefruit or “Hollywood” diet, promoted by California citrus growers, had dieters chasing every meal with a grapefruit or its juice. Greta Garbo’s personal dietician, one Gayelord Hauser, achieved celebrity-diet-guru fame with a regiment relying heavily on brewers’ yeast, wheat germ, and powdered milk. The Depression proved that any positive associations of plumpness with prosperity had vanished for good; even in these leanest of times, a lean body was the ideal.

Hollywood actresses, on screen and in gossip magazines, followed the lead of the flat-chested flappers of the previous decade by securing thinness as an index of youth and beauty. In the silent-movie era, a girl’s adorably dimpled cheeks might have been an asset, but by the 1930s the camera had zoomed out to take in her whole figure, draped in bias-cut gowns that shimmered over the body with no visible means of support beyond the musculature of the disciplined wearer. Brash, busty Mae West, who ridiculed dieting (“the only carrots that interest me are the number you get in a diamond”) was elbowed out by the arrival of the prudish Hays Code, enforced in earnest from 1934. The new screen sirens looked very different—they were angular and athletic, like Katharine Hepburn. Studios watched their young stars’ weight carefully, restricted their food, and even fed them amphetamines to keep their energy up and their appetites down. Then as now, an actress’s reducing regimen was mostly made up of ingredients as healthy as a Prohibition cocktail: coffee, cigarettes, drugs, laxatives and lies. In such a climate, the impact of a miracle weight-loss drug is easy enough to predict.

But the Stanford doctors, apparently, did not see it coming. The year after their first published study of DNP, they offered an update on the drug’s effects, in a report that hums with panic. “The total amount of the drug being used is astonishing,” they write, noting that on top of nearly 5,000 patients being treated by a doctor, “upward of 20 wholesale drug firms are marketing the compound, which suggests that a considerable population is being medicated.” In the United States alone, at least 100,000 people were taking some form of commercial DNP by 1934, under names like Corpu-Lean, Redusols, Formula 281, and the neatly reductive Slim, which were sold over the counter at drugstores. And as with any drug that promised magical results fast, there wasn’t much incentive to follow the instructions. If one pill made you smaller, how much smaller could ten make you?

In June 1936, TIME wrote that 100 women in Los Angeles alone “were known to be blind or partly so with cataracts” as a result of taking DNP-based diet drugs—listing fifteen separate brand names in a two-paragraph report—and that a local health officer had launched a drive to banish them. Seven people, by that point, had died. But it wasn’t until Congress passed the Federal Food, Drug, and Cosmetic Act in 1938 that there was any consistent legal structure in place to regulate over-the-counter pills and potions. For the first time, new drugs had to be proven safe and effective before they were made available for sale, and the vast, vague category of cosmetic treatments was brought under the umbrella of the law. The first act of the newly empowered Federal Trade Commission was to yank DNP from pharmacy shelves.

“Boiled Alive by Internet Slimming Pills” was the delicate headline the British tabloid The Daily Mail slapped on a report of the death of 23-year-old Sarah Houston in 2013. Houston was the first of three young women in the UK to die as a result of buying DNP-laced weight-loss drugs online—all of whom had struggled with some form of eating disorder before their gruesome deaths. Interpol last year issued a global alert following the UK deaths, a near-fatal case in France, and a drug seizure in Australia, and a total of some 60 deaths worldwide.

Given the intractable crisis of obesity and the stubborn worship of skinny bodies, it’s somewhat surprising that it has taken this long for the miracle drug to make a comeback. There was a previous resurgence in Texas in the 1980s, courtesy of a Russian doctor named Nicholas Bachynsky, who gleaned his knowledge from medical texts he translated for the American government—during World War Two, it seemed, some Russian troops had been fed DNP to keep them warm. Bachynsky grew rich peddling the drug secretly in a chain of clinics, and after he was imprisoned for insurance fraud, passed on his knowledge on to the bodybuilding guru Daniel Duchaine, who was doing time for crimes related to his passionate promotion of steroids. Via Duchaine and the bodybuilding community, DNP once again began to find its way to users, helped along by the internet’s well-greased channels of illicit commerce—although online bodybuilding forums are full of warnings against touching the stuff. Last month, a California man was given three years’ probation for selling DNP via eBay to a man in Rhode Island, who died of an overdose in 2013. The FDA, after its proactive start in the late 1930s, is now pretty much toothless on weight-loss supplements: if they contain ingredients that were sold legally before the early 1990s, there’s no obligation to prove that a new concoction is effective, or safe, before it’s put on the market.