For more than 45 years our doctors have combined in-depth nutritional lab testing, a comprehensive medical evaluation, and the utilization of a variety of holistic, non-toxic treatments and services to provide a customized, holistic treatment plan. The Riordan Clinic is a not-for-profit 501(c)(3), nutrition-based health facility with three locations in Kansas: Wichita, Hays, and Overland Park (which is in the Kansas City metro area). The Riordan Clinic was established as a 501 (c)(3) non-profit organization with missions in research, provider education, and patient education.