The Fountain of Youth or Medical Baloney?

Sept. 23, 2008— -- It's nearly impossible, even now, to see Suzanne Somers and not be reminded of her trademark laugh.

Her Chrissy Snow character was one-third of the "Three's Company" trio, which dominated prime time television in the 1970s and '80s. Sweet but simple, Chrissy became an enduring television icon.

But playing that role would not be the last chapter in Suzanne Somers' story.

Watch the story tonight on "Nightline" at 11:35 p.m. ET

She is now a best-selling fitness and nutrition author with more than 10 million books in print.

"The theory behind anti-aging is keeping your insides young -- keeping your body strong," Somers said.

Now 61 years old, Somers brought "Nightline" along to visit one of the doctors she champions in her latest book, "Breakthrough." She is the self-styled face of what she describes as the visionary field of anti-aging medicine.

"I'm probably more involved with doctors than the average person," Somers said. "I don't think we practice health care in this country. I think we practice disease care."

Central to her message is the use of unproven, potentially dangerous hormonal therapies, making Somers as controversial as she is successful.

"I'm probably the happiest I've ever been in my whole life," she said. "And the most content. The most fulfilled. The most satisfied. Doing what I love."

She played Chrissy Snow for six years until a contract dispute forced her out of "Three's Company." She said the show's producers literally banished her from contact with the rest of the cast.

"They forced me to finish out my contract but relegated me to one minute at the end of the show," she remembered. "I was not allowed to interact with anybody else in the cast. An armed guard would meet me at the back door of the studio and walk me in so that I wasn't able to interact with anybody, and that was traumatic."

But her life after so much success in a short amount of time was not one Somers had hoped for.

"I couldn't get a job anywhere," she said. "I couldn't get an interview anywhere. I was considered trouble in the industry. And one day,I thought, 'Why don't I focus on what I do have?' And I thought, 'What do I have?' I have enormous visibility. Everybody in this country knows my name. That's worth something."

Somers enjoyed huge success using her name to sell a long list of lifestyle and fitness products, including the iconic ThighMaster.