Why does Joint Xtra only contain 150 mg of MSM? I know that the daily effective dose for MSM is 500 mg.

The key ingredient in Joint Xtra is Glucosamine, and with 1,500 mg of Glucosamine, it is hard to add more MSM there. Also, MSM along with other nutrients, herbs, and botanicals like Chondroitin, Boswellia, Turmeric, Ginger, Horsetail, and Cat's Claw work together for joint extra strength.