The insomnia is probably due to the lack of the calming effects of progesterone. Replacing progesterone usually improves insomnia. Many women complain of poor concentration and lapses in memory during menopause. Progesterone is involved with providing insulation to nerve cells. Myelin which surround nerve cells, acts like rubber around electrical wires.
Myelin insulates nerve cells and improves conduction of nerve impulses.
Decreased progesterone may interrupt the production of myelin and interfere with brain impulses. Estrogen without the proper amount of progesterone can interfere with thyroid hormone function. Thyroid hormone is necessary to properly metabolize food and convert it into energy. If thyroid hormone is not functioning properly women experience weight gain, fatigue, food cravings and symptoms of low blood sugar. What may be most disturbing to women is the loss of scalp hair and the growth of facial hair after menopause.