Yes, it’s true: Millions of people pay large amounts of money for something that does absolutely nothing. Glucosamine, alleged to relieve pain and slow damage in arthritic joints, does neither, at least in knee joints, according to a study published in the journal Arthritis & Rheumatology. HealthDay reports that researchers, working with 200 people with mild to moderate pain in one or both knees, randomly selected some to drink 1,500 milligrams a day of glucosamine and some to get a placebo added to a 16-ounce bottle of diet lemonade for 24 weeks. At the end of that period MRI scans showed no reduction of damage to cartilage, and participants reported no difference in pain relief. Read more in HealthDay.