This study examines the effect of hormone and amino acid levels on mood changes in women at mid-life. The research involved both a clinical trial of the application of hormones and amino acids to effect mood changes is women at mid-life, and a laboratory analysis of synthetic and natural progesterones. The clinical trial involved a detailed biochemical study of two women and a less intensive study of two other groups of women identified as Estrogen Dominant or Estrogen Deficient. Depending on whether the women were Estrogen Dominant or Estrogen Deficient, they responded well to natural progesterone or estrogen, respectively. Even when natural estrogen was given, it was never without natural progesterone.

http://orthomolecular.org/library/jom/2001/articles/2001-v16n03-p141.shtml