Mannatech's Science Team

Robert A. Sinnott, MNS, PhD
Mannatech's Chief Science Officer and Senior Vice President of Research and Product Development

Robert A. Sinnott, MNS, PhD, Mannatech’s Chief Science Officer has held scientific positions in both industry and government over the past 15 years. He is a three-time alumnus from Arizona State University in Tempe, Arizona where he earned a Bachelor’s Degree in biological sciences in 1987; a Master of Natural Sciences Degree in 1989; and a Ph.D. in 1995. During his graduate training, Dr. Sinott’s primary focus was plant medicinal chemistry and plant biotechnology.

In addition to business endeavors, Dr. Sinnott was instrumental in establishing the science branch of a non-profit educational institution for training economically-disadvantaged students in science-based careers. The program was quickly granted numerous awards by the Department of Education and the U.S. Department of Agriculture and continues to expand its influence.


Stephen Boyd, M.D., Ph.D.
Mannatech's Senior Medical Director

Stephen Boyd, M.D., Ph.D., serves as Sr Medical Director in Mannatech, with responsibility for the medical research program, liaison with health professionals and the product safety monitoring program. Dr. Boyd graduated with a B.S. and Ph.D. degrees in chemistry from the University of Glasgow in Scotland, followed by a Post-Doctoral Research Fellowship in thermodynamics at the State University of New York. Following industrial experience in chemical research, he returned to college and graduated with an MD degree from the University of Toronto, Canada. Dr. Boyd has spent fifteen years in practice as a Family Physician in the US and Canada and sixteen years in pharmaceutical and nutritional research. He is currently a member of the American Academy of Family Physicians, the Texas Academy of Family Physicians, the American Medical Association and is a Diplomate of the American Academy of Wound Management. In 2001 Dr. Boyd was elected a Fellow of The Royal Society of Medicine in London.


Steve D. Nugent, NMD, PhD, PDD, CNC
Mannatech's Executive Director of Complementary Health and Education

Stephen D. Nugent, N.M.D., Ph.D., P.D.D., C.N.C., is the Executive Director of Complementary Health and Education for Mannatech. He has earned six degrees, graduating with honors at both undergraduate and graduate levels. He pursued evening courses at National University’s San Diego and Vista campuses while serving as a U.S. Marine. He obtained his doctor of naturopathic medicine degree as well as a Ph.D. in psychology from Clayton University in Missouri. He enrolled in a Professional Development Degree (P.D.D.) program at the University of Michigan’s Dearborn campus and graduated with top honors. Dr. Nugent is the current President of the International Association of Complementary Medicine as well as the President Emeritus of the American Naturopathic Medical Association. He is considered an expert in the therapeutic use of dietary supplements.