Excess stress can rob the body of essential nutrients, particularly the B vitamins, and it lowers the effectiveness of the immune system. As B vitamins are depleted, they are no longer fully available for energy production and proper mental function, resulting in tiredness, stomach upset, a variety of nervous ailments, and lowered immunity to colds, viral infections, and other diseases. Jamieson offers a variety of B complex supplements and stress relief formulas containing melatonin to help reduce feelings of stress and provide a restful sleep.