I am delighted with the Opti MSM sulfur by Dr. Best. Open now 3 capsules daily (slow creep with 1 capsule / day helps the initial incidental / detoxification symptoms of headache or tension feelings to small pimples to minimize on the scalp) and have therefore my Knee pain (due to a Baker's cyst, which I did not want to be removed surgically) reduced to almost 0. My nails are super tight, hair and skin become more beautiful.
Since MSM slightly affects blood thinning and increases cell permeability, it supporting the effectiveness of other medications or dietary supplements and you need if necessary. Less. If someone takes as aspirin or warfarin, they need possibly less of it. Is everything in the book by Dr. Liebke (MSM Super a substance from nature) which I also highly recommend.