How Much Glucosamine/chondroitin/msm Should I Give My 14 Year Old Weimaraner?

He’s been having pretty bad hip problems for the past few months, so I picked up a bottle of “Triple Flex” pills at Walgreens. He is a pretty big dog, around 100 pounds.
They have 500 mg of Glucosamine Hydrochloride, 400 mg of Chondroitin Sulfate, and 125 mg of Methylsulfonylmethane in each pill.