IdeaSphere made headlines in November 2005 when it acquired the non-ephedra assets of beleaguered supplement maker Metabolife, which was at the center of much of the product liability storm over the banned herbal.
Other brands of the Michigan-based company include Twinlab, Ultra Harvest and Nature's Herbs.
The terms of the latest agreement were not disclosed, but IdeaSphere is to be responsible for all retail and direct marketing of the brand, including customized supplement and vitamin regimes through DrWeil.com.
"The addition of the prestigious Weil brand enhances our already strong stable of product lines and aligns perfectly with our company's mission and vision for the future," said president Mark Fox.
Dr Andrew Weil said: "Our companies share similar philosophies and a commitment to nutrition and evidence-based science research, and we both create products with premium ingredients that can be applied to an individual's lifestyle and stage of life.
"We are pleased to be associated with an industry leader like IdeaSphere, and we are confident this new arrangement will expand our access to consumers interested in incorporating the products and healing modalities of integrative medicine into a healthy lifestyle."