Are there side effects when taking 1200mg of chondroitin sulfate, 1500mg of glucosamine and 1000mg of fish oil? (prescribed to help lubricate knee)

May raise blod sugar. There is some limited data to show elevated blood glucose levels in people with diabetes who take glucosamine and chondroitin suflate. However this does not seem to happen in people without diabetes. In general, glucosamine and chondroitin sulfate are very safe, but they should be stopped at least one week prior to any surgery as they may have a blood thinning effect.
No. Generally no side effects but no real hard science that clearly supports benefits.