In 2014, the Food and Drug Administration told Herbalife to take down a YouTube video that featured a former F.D.A. official implying that the agency approved weight loss shakes and other supplements.

And in a 2016 settlement with the Federal Trade Commission, Herbalife agreed to pay $200 million and was forced to restructure the business to settle charges that it deceived customers into thinking they could make substantial money selling the product.

Herbalife did not respond to numerous requests for comment.

“The company is too controversial historically,” said Arthur Caplan, director of medical ethics at the New York University School of Medicine. “It has a very non-illustrious history with regulatory bodies, association with a product of controversial and most likely dubious merit, and is not where the cancer society wants or ought to be.”

The Herbalife Facebook page shows both the cancer society and the company’s logo, with the phrase, “Working Together to Make the World Healthier and Happier and Free from Breast Cancer.” It does carry a disclaimer noting the cancer society does not endorse Herbalife products.

Dr. Caplan said the disclaimer isn’t enough. “Some people are going to think that there’s an implicit endorsement,” he said, “either because they don’t look at the website or they just see the bottle and presume a partnership.”

Historically, the cancer society’s revenue was heavily reliant on walks, including Relay for Life and Making Strides Against Breast Cancer, said Michael Reich, a spokesman for the organization. But during the past decade, he said, donations patterns have changed and walks, in particular, have become less popular.

“Because A.C.S.’s walks generated so much revenue and were such a large part of our portfolio, our declines were much more pronounced than some other organizations,” Mr. Reich said. “We have been re-engineering and diversifying our revenue portfolio, and partnerships are playing a key role. This takes time to build, but we are making tremendous progress.”