I discuss details of history, exam, labs and x-rays. Maximizing the Arthritis Cure chapter 3. Sometimes, diagnosis is obvious, but secondary causes of OA must be ruled-out. Anything that has an effect on the body probably will have some side effects, especially in high doses. Yes, once people have done the initial 2 months, PRN or as needed is fine.
Dose depends on weight.
If you just take the pills, you may be doing more harm than good. Have a thorough consultation with a physician. Take glucosamine and chondroitin sulfates to repair damaged joints. Improve your biomechanics to counteract stress to your joints. Eat a healthful, joint-preserving diet.