Dexatrim was an over-the-counter diet pill whose key active ingredient was phenylpropanolamine, commonly abbreviated as PPA. Sold from the 1970s through 2000, it was one of the most popular weight loss supplements in the United States before the FDA pulled PPA from the market due to stroke risk. The story of what was in Dexatrim is largely the story of this single ingredient and why it was banned.
Phenylpropanolamine: The Core Ingredient
Phenylpropanolamine is a synthetic compound closely related to adrenaline and amphetamine in its chemical structure. It belonged to a class of drugs called sympathomimetic amines, meaning it mimicked the effects of your body’s “fight or flight” stress hormones. PPA worked as an appetite suppressant by activating specific receptors in a part of the brain that regulates hunger. When PPA stimulated these receptors, the brain’s hunger signals were dampened, making users feel less inclined to eat.
PPA wasn’t unique to Dexatrim. It also appeared in dozens of cold and allergy medications as a nasal decongestant, since the same mechanism that suppressed appetite also constricted blood vessels and reduced sinus swelling. But Dexatrim was by far the best-known weight loss product built around PPA.
How Dexatrim Was Taken
The original Dexatrim formula came in two dosing formats. The standard version contained 25 mg tablets taken three times a day, half an hour before meals. An extended-release version delivered 75 mg in a single capsule taken once in the morning. Either way, PPA-based weight loss products were only intended for short-term use, with a recommended limit of 12 weeks.
Beyond PPA, Dexatrim capsules contained inactive ingredients typical of over-the-counter pills: binders, coatings, and fillers. Some versions also included caffeine to boost the stimulant effect. But PPA was always the ingredient doing the heavy lifting for appetite suppression.
Why the FDA Removed PPA From the Market
On November 6, 2000, the FDA requested that all companies stop selling products containing phenylpropanolamine. The decision was driven by a large case-control study involving 702 stroke patients and 1,376 comparison subjects, all between the ages of 18 and 49. The study found a clear association between PPA use and hemorrhagic stroke, a type of stroke caused by bleeding in the brain.
The risk was particularly pronounced in women. Women using PPA for weight control showed an increased stroke risk within three days of starting the drug. Women using PPA as a nasal decongestant faced elevated risk within the first day of use. Because PPA raised blood pressure by constricting blood vessels throughout the body, it could cause vulnerable blood vessels in the brain to rupture. The FDA concluded the risk was serious enough to pull PPA from all drug products, not just diet pills.
Lawsuits and the Aftermath
The FDA’s action triggered a wave of product liability lawsuits against Chattem, Inc., the company that manufactured Dexatrim. The litigation stretched over four years before a settlement was approved by a federal district court. Chattem took pretax charges of $15.8 million to resolve the PPA-related cases, roughly half of what the company had originally estimated the litigation would cost. The charges were covered by a combination of insurance proceeds and cash reserves.
What Replaced PPA in Dexatrim
After the PPA ban, Dexatrim didn’t disappear from store shelves. The brand was reformulated with different active ingredients. Early reformulations used ephedra, another stimulant-based appetite suppressant, but ephedra was itself banned by the FDA in 2004 due to heart attack and stroke risks. Later versions of Dexatrim shifted to herbal and caffeine-based formulas, including green tea extract and other plant-derived compounds marketed as metabolism boosters.
None of the reformulated versions carried the same pharmacological punch as the original PPA-based product. PPA was a genuine appetite suppressant that acted directly on brain chemistry. The herbal replacements that followed operate through milder, less well-established mechanisms. The Dexatrim name has continued to be used on various supplement products over the years, but the product that made the brand famous, the PPA-powered diet pill of the 1980s and 1990s, no longer exists in any form.