Several executives, though, say they cannot imagine turning their back on Mr. Hatch.

“Some folks get elected, go to Washington, forget where they came from,” John F. Gay, chief executive of an industry trade association, said last year in introducing Mr. Hatch at an industry convention in Las Vegas. “Others get elected, go to Washington, and use the knowledge they have gained, the relationships they’ve built, the power they have developed over the years of incumbency to help the folks who got them there. That is the type of person that Senator Hatch is.”

Hatch to the Rescue

Just to the left of the entrance at Xango’s corporate headquarters here in central Utah is the “Million Dollar Club,” where independent sales agents learn the pitch for the company’s $40-a-bottle juice, made from a Southeast Asian fruit called the mangosteen.

One night in March, Dr. Vaughn T. Johnson, a Xango distributor, delivered part pep talk, part medical seminar, in describing extraordinary powers attributed to mangosteen. Studies showed, Dr. Johnson said, it was “anti-tumor,” “anti-obesity,” “anti-aging,” “anti-fatigue,” “antiviral,” “antibiotic” and “antidepressant.”

“How do I know this isn’t just snake oil?” Dr. Johnson, an osteopathic physician, asked. “It’s a really simple answer. A company that is selling snake oil is not going to stay in business for almost 11 years and grow as fast as this company is growing.”

When Utah became a leading center of supplements a half century ago, an industry pioneer named John R. Christopher boasted that his more than 50 herbal formulas offered “almost miraculous healings.”

But by the early 1990s, the Food and Drug Administration had become uneasy about the growing number of exotic product and health claims, particularly after more than 20 deaths were attributed to a “natural” sleep remedy. After the agency conducted raids across the country to confiscate supplements deemed unsafe or sold for unapproved uses. Mr. Hatch came to the rescue.

Under legislation he pushed through Congress, nutritional supplement companies could introduce products without F.D.A. approval, and make general health claims without proving their effectiveness or safety. The legislation covered a wide range of products — not just vitamins and minerals, but also herbs, essential oils and other substances — and was written to give companies a lot of leeway in their marketing claims.