The following claims have been made from what I can research:
Improves eyesight
Improves aerobic performance
Strong calming effect
Stabilises thyroid
Ie a very wide range of possible areas being addressed.
I take 1000 a day (500 had little effect) and I can claim early support for items 1 and 3 above.
I was in a restaurant last week and could actually read the menu without resorting to the mobile phone torch.
Alongside magnesium they seem the only 2 supplements that make a directly measurable effect for a hypo sufferer. Others like D, C and A I can take for insurance purposes but seem to have nothing of the same effect if I stop them from time to time.
taurine seems to get little to no mention here so thought I would add my thoughts (of course personal to me and no advice intended)