TH and demyelinating disease: On the basis of these results [13,14,15], numerous independent labs have demonstrated that TH supplementation (by triiodothyronine (T3), thyroxine (T4), or TH analogs) favors myelin protection/repair, overcoming the oligodendrocyte precursor cell (OPC) differentiation block, protecting myelin and axons, and ameliorating the clinical outcome in experimental models of inflammatory/demyelinating diseases [15].