I found it worked for me, but the effect was small. I read up about it, and it seems that the picolinate form is best to use, then the GF type used by body builders.
i think it helps to reduce insulin resistance in the muscle cells, but there sre not many formal studies into it. I also note that it only seems to work if your diet is already low in chromium, so you should not need to supplement if you are on the average Western diet, which includes green leafed veg.