If your morning routine includes vitamin supplements, you may not be getting results. New research says glucosamine does not ease pain.

Study results just published say glucosamine supplements don’t help knee or hip pain. And, in fact, have no more effect than a dummy pill.

Overall, the effects of glucosamine and the placebo on pain and physical functioning did not differ, either in the short term or one to two years later.

The supplement was also no better than placebo among groups based on age, body mass index or gender.

Dr. C. Kent Kwoh, director of the University of Arizona Arthritis Center in Tucson, says consumers should be cautious about spending money on unproven treatments.

Americans spent nearly $13 billion in 2012 on natural product supplements, and glucosamine was one of the most popular, according to the U.S. National Center for Health Statistics.