Methylsulfonylmethane (MSM) is a sulfur compound. Sulfur is a mineral that is present in body proteins, especially in connective tissue. Keratin contains lots of sulfur. Keratin is present in the skin, nails and hair. The typical rubbery smell of burning hair comes from sulfur. MSM is a good source of organic sulfur.
If you are deficient in Sulfur, you will benefit from MSM supplementation.
But deficiency is very unlikely in individuals who eat meat, milk products or vegetables.
MSM is a small molecule and it penetrates the skin (and even the blood brain barrier) easily. MSM itself is used as a skin penetration enhancer – to facilitate the penetration of other substances. That is why it is not necessary to use dermarolling prior to its application.
MSM is used for skin lightening and hyperpigmentation spots as a safer alternative to Hydroquinone.
It is also used (usually orally) in osteoarthritis in combination with Glucosamin and Chondroitin for its anti-inflammatory and analgesic effects.
Yes you can take MSM orally. Many studies have found MSM intake safe.
Toxicity of Methylsulfonylmethane in rats:
https://http://www.ncbi.nlm.nih.gov/pubmed/12387309 Oral developmental toxicity study of methylsulfonylmethane in rats:
https://http://www.ncbi.nlm.nih.gov/pubmed/17258373 Nonetheless, I think that a healthy diet is the best source of Sulfur.
It is not true that food processing destroys Sulfur, for Sulfur is an element, and elements can only be transmutated by high-energy nuclear reactions. And even elemental Sulfur is well-absorbed.