FYI, I bought
this item from Amazon. Two 4-oz. bottles, with droppers, for $30. If used only as eyedrops, it's enough to last a lifetime! MSM is a sulfur compound and is also widely used for joint pain. So if you have aches and pains these drops can also be added to your favorite liquid -- a couple of drops to 8 oz. -- and taken internally. Can't hurt, and there are many anecdotal testimonies to its efficacy. PS: I am not a doctor. In the end, you're on your on. We all are.