Sulfur?

I was diagnosed 5 years ago with Hep C
when my routine blood donation was rejected by our local blood bank.  My
Dr has been watching my enzynme level and I haven't had any serious symtoms (symptoms).
I have hypertension and it is controlled with medication...I also take Max Milk Thistle.  
I have recently developed joint pain in both knees and my hands...Have been taking a 'natural' supplement that contains 'methyl-sulfonyl-methane' (50 mg) with my Dr's knowledge.  I now see a more powerful version of the supplement offered by the same company
...I understand that MSM is a dietary
sulfur...my question is...would it possibly be harmful (or helpful) to my liver in a higher daily dose?   My next appointment is a month away..and any insight you could offer will be appreciated!    Thank you!