I just started taking D-ribose today (5 grams of powder 3x a day). How long until I know if it's going to work? I also take a mutlivit., glucosamine/chon., Celedrin, flax oil, extra magnesium, and Zyflamend. I stretch (15 minutes) and walk (30 minutes) every morning, but still ache and get tired easily. I eat well and drink lots of green tea and ginger tea.