"When you talk to patients who've lost 30, 40, 50 pounds and you see and talk to them and they call you back and they say, gee you know their life has changed, it's a wonderful thing," he said, "and it's really not fair not to let people have this."
Hirsch provided "20/20" with a handful of happy customers, including one man who claimed he lost 120 pounds.
"You know there is a very interesting plaque I once saw at the National Institutes of Health," Peeke said. "It said in God we trust, everyone else must show data. People believe what they want to believe."
Especially when the people in the Hirsch study weighed themselves and reported their own weight losses with no outside checks.
"When you cannot monitor and supervise participants in a trial, that's a big problem because people will report what people will report," Peeke said.
When pressed, Hirsch did acknowledge some mistakes in the selling of the scientifically unproven Sensa flavor flakes. First, the promotional video falsely claims a control group used fake flakes to compare how much weight they lost versus those given actual Sensa.
"That's something the distribution company did," Hirsch said. "That's not something I did. Obviously a misunderstanding."
Peeke and Bausell also told "20/20" that Hirsch used an ingenious marketing ploy.
While most clinical studies pay the participants for their time and effort, Hirsch actually asked his participants to pay him $49 a month, a notion that made Bausell laugh out loud.
"It's a double-dipping situation," he said. "I mean, it's really genius." But Hirsch says it happens all the time, and that the U.S. Food and Drug Administration approves of the practice.
"At the end of the day, doing this study was not something we made money from," he said, adding that Sensa broke even.
"20/20" found four people who said they lost weight as part of Hirsh's studies and they had one thing in common. Afterwards, none of them kept the weight off. "My experience with the sprinkles for me, it really didn't work," according to one study participant.
Others said the weight came back once they stopped using the flakes. But once the study's over, Hirsch said, it's over.
"There are different things that could've made the study more elegant," he said. "Bottom line is people lost 30 pounds in six months."
At least-- they say they did.