Unfortunately, some well known national brand companies have been selling highly diluted MSM to their customers. One brand contained less than 3% pure MSM, while stating on their label, "The pure MSM in this product is the highest quality available." Which was probably true but what the company failed to say was that in addition to the pure MSM, the capsules contained 97% fillers. If you have used MSM in the past without getting the health results you were hoping for, there's a good chance the product you tried was not full strength and pure. Please do not deny yourself the benefits of MSM without trying truly pure MSM. The following is the simple way you can test your MSM for purity: Empty the contents of one capsule or one half teaspoon of MSM powder into a clear glass of water. The MSM will immediately sink to the bottom, and dissolve within a few minutes. All the contents of capsules or powder containing fillers will not sink to the bottom, and not all of the material will dissolve. You can stir it or not stir it, either way the results will be the same: the MSM will immediately sink to the bottom and dissolve and the other "stuff" will float to the top. Granted, this test doesn't tell you exactly what is there but it will surely tell you what isn't there-pure MSM in any form will not float. I thought this was an interesting since we're taking MSM.