Are you one of millions of Americans who experience Seasonal Affective Disorder (SAD)? It can happen during the winter months when you get less exposure to radiation from the sun. It may be related to changes in hormones such as melatonin, but it can also be related to low vitamin D levels in the body. The PatchAid Vitamin D3 and Calcium Patch is high in vitamin D3 and you might want to ask your doctor about whether it can help keep your mood normal this winter.