What is Msm? MSM is a sulfur-based organic compound called Methyl Sulfonyl Methane. It is the organic sulfur source with the highest bioavailability. It is found in all living organisms. MSM powder, which is in crystal white form, can be easily dissolved in water. MSM is a recognized as safe (GRAS) approved substance. How to Use MSM? Although there is no clear usage dose of MSM, it is mostly used orally by adults in doses of 1-6 grams per day for up to 16 weeks. MSM powder is water-soluble and can be added to water, juice, smoothies, protein shakes and other cold drinks. There is not enough reliable information to know whether MSM is safe to use while pregnant or breastfeeding. If you are pregnant or breastfeeding, consult a healthcare professional first.