[Marcy]

I was wondering if you guys have any recommended brands, many amazon.com reviewers have claimed on many brands that they failed the purity test.

I've been using Doctors Best but am switching to Swanson's listed by iaboy after having some stomach issues with the tablet form. See here for a good read on how to use MSM:

http://a1msm.co.uk/supplements/msm-methylsulfonylmethane/how-to-take-msm-supplement.html