Kirkland Signature Vitamin D3

Kirkland Signature is the private-label brand of Costco Wholesale Corporation, an American multinational retail corporation. Launched in 1995, the brand was named after the location of Costco's corporate headquarters at the time, which was Kirkland, Washington. The brand's philosophy is to provide high-quality items at prices lower than national name brands by working directly with suppliers and maintaining strict quality control.

Kirkland Signature supplements, such as this Vitamin D3, are manufactured through partnerships with various high-quality pharmaceutical and dietary supplement manufacturers. While the specific supplier for this exact bottle is often proprietary, Costco maintains rigorous third-party auditing to ensure the supplements meet Pharmacopeia (USP) standards. Ownership of the brand remains entirely with Costco Wholesale, headquartered in the United States, which manages global distribution through its warehouse club network.