I did a search Den, and found this:
Here's the link
http://www.naturalchoices.co.nz/main/faq-msm.htm#How soon can I expect results from taking MSM
Will I experience any side effects from taking or using MSM?No. The only side effects are stronger fingernails and toenails, and your hair grows faster, because these all contain more Sulfonyl Sulfur.
MSM is no more toxic than pure water. Any excess MSM in your system will stay in the blood stream for 12 hours, removing toxins and cleaning the interior walls of your arteries. You cannot overdose on MSM. Your body will use only what it needs.
One in five people taking MSM may experience detoxification symptoms in the first 1-10 days, during which toxins are flushed from the system.
Symptoms may include diarrhoea, skin rash, and/or possibly headache, along with several days of fatigue. In general, the more intense the symptoms, the more toxins there are in your body, and the more MSM is needed to help detoxification. To ease detoxification symptoms, reduce your dose rate to about 750mg, and gradually build back up to the recommended dose of one 1200mg tablet per 27kg of body weight twice per day.
Otherwise, for maximum benefit from MSM, it's recommended that you use it indefinitely for maximum results. After initial detoxification, physical energy levels should increase noticeably.
There are no negative side effects from applying Rich's MSM Lotion to the skin