Dr. Mehmet Oz is comfortable in front of cameras, but on June 17, he faced a very different audience: the Senate Subcommittee on Consumer Protection, Product Safety and Insurance.

The TV doctor looked deadly serious as Sen. Claire McCaskill, the Subcommittee's chairwoman, reprimanded him for touting unproven weight-loss supplements on The Dr. Oz. Show.

"I would give my audience the same advice I give my family, and I have given my family these products," he responded.

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While it was a strong comeback, Dr. Oz left Washington, D.C., feeling "not overly impressed with his performance," says an insider. "He felt like they were looking for a mea culpa, but he believes the issues are more complicated."

The problem, the senators argued, is that he gives viewers "false hope" by praising little-studied weight-loss supplements.

Following the hearing, Dr. Oz, 54, admitted to Closer, "My enthusiastic language has made the problem worse at times," but that he'd use "an abundance of caution" when talking about future diet research and products.

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Among the changes he's pledging to make, Dr. Oz "wants to be more involved in preparing his shows," says a source close to the show. "He'll talk to producers more in-depth and spend a good amount of time pouring over materials so that he really knows his stuff — and the products he may be giving a seal of approval too."

While the scolding he received on Capitol Hill might have bruised his ego, few believe that Dr. Oz's brand has been seriously damaged.

"Most people have already made up their mind about Dr. Oz, and they like him and trust him," says PR professional Howard Bragman, who calls this event a "speed bump, not a sinkhole" in Dr. Oz's career.