Well I've just started taking MSM...the capsules I have are 1000mg and the label reads "take one or two a day". I take one a day, don't know if thats any help
Start with 3g a day and boot up to 6g a day depending on what your hair growth rate is. MSM is only used to excelerate hairgrowth it will not make more hair grow or thicker hair grow. After 4 months on the stuff taking 5g of powder a day I found that this is not essential in my regimen.