Rhodiola as been used for centuries to help cope with the cold winters in Norway, Sweden, and Iceland and may have been used by the Vikings to improve stamina, reduce symptoms of stress, improve fatigue, and help fight off infections.

European researchers reviewed a number of studies testing the effects of ALCAR (N-Acetyl-L-Carnitine) on depression. The reason, according to the researchers, is that a deficiency in brain ALCAR activity appears to play a role in the risk of developing depression.