No magic...
          just real science!

There are thousands of studies regarding all types of 'glucosamine' over the decades. The following link are abstracts of a few of the key studies proving somethings, and disproving other things you might have heard.

Spanning nearly 40 years, hundreds done by unbiased independent third parties from around the world, involving thousands of test subjects, by hundreds of scientists, often double blind placebo studies.  The science is real, and there were reasons the NIH, and those involved with the GAIT study completely avoided the Glucosamine Sulphate's... particularly the 2KCl form, which has decades of major positives, proven results, and real controlled study results backing up the efficasy. 

 Glucosamine Sulphate Study Results