GC-1 is structurally very similar to thyroid hormone T3:

                      CH3
    |                 |
    |     .     .     |
   / \   / \   / \   / \
  /   \ / _ \ /   \ / _ \             This is GC-1
       | / \ |     | / \ |
       | \_/ |     | \_/ |     .      OH
      / \   /     / \   / \   / \    /
     /   \ /     /   \ /   \ /   \  /
   HO     '   H3C     '     O     ||
                                  ||
                      I           O 
                      |
    I     .     O     |
     \   / \   / \   / \
      \ / _ \ /   \ / _ \    H2N      This is T3
       | / \ |     | / \ |     |
       | \_/ |     | \_/ |     |      OH
      / \   /     / \   / \   / \    /
     /   \ /     /   \ /   \ /   \  /
   HO     '     I     '     '     ||
                                  ||
                                  O

This kind of stuff (thermogenics, metabolic accelerators, fat burners, etc) has been used for ages in the gyms in one form or another. Many of the so called "supplements" always regulate the thyroid... So I wouldn't consider this a big "breakthrough" for weight loss.

The short path to weight loss has hidden dangers. Experts don't recommend losing more than 2 lbs/week. Surely you can lose more than that, but not as safely. The winning formula will always be: "Eat better, exercise more".

Evidently we've know about this for at least 10 years: http://www.ncbi.nlm.nih.gov/pubmed/15109613