The FDA’s ad police warned a Campbell, Calif.-based company to stop claiming that its prescription diet pill can help patients lose weight three times faster than diet and exercise alone.

In an untitled letter to Vivus, the FDA’s Office of Prescription Drug Promotion says that the company is making misleading claims about Qsymia (phentermine and topiramate extended-release) capsules on its website.

Vivus’ site promises, among other things, that “On average, prescription Qsymia can help you lose weight 3 times faster than diet and exercise alone,” the FDA says, adding that the site claims the drug can take up to 5 inches off patients’ weight—and 32 pounds off the scales—in a little more than a year. None of those claims will hold up to the weight of clinical evidence, the FDA says.