Researchers from Madrid, Spain, compared the benefit of glucosamine sulfate versus acetaminophen (Tylenol) on the symptoms of knee osteoarthritis during a 6-month treatment course. Patients were randomly assigned to receive oral glucosamine sulfate 1,500 mg once daily, acetaminophen 3 gm a day, or placebo. There were more responders to glucosamine sulfate (39%) and acetaminophen (33%) than to placebo (21%). The findings of this study indicate that, in the long run, glucosamine sulfate is more effective than placebo and as or more effective than acetaminophen in treating knee osteoarthritis symptoms.
Comments: Acetaminophen reduces joint pain 
quicker than glucosamine but it can cause harm to the liver, even at doses of one gram a day. I do not think it is a good drug to be taken long term for a chronic condition such as osteoarthritis. There is a possibility that if glucosamine is combined with chondroitin and other nutrients or herbs it may be more beneficial than by itself. I wonder how many years it will take for the American Board of Family Medicine to include natural supplements as options in their multiple choice questions and answers.