Doctor's Best Synergistic Glucosamine MSM formula with OptiMSM provides nutritional support to help you maintain your healthy joints. Each six-capsule serving in this 180 count bottle contains 1,500 mg. of glucosamine sulfate plus 3 g. of msm. We also add vitamin c, potassium and chloride to this formula to help in the production of collagen, a structural protein. These capsules are gluten-free for use by those with dietary restrictions.