Hot flashes erratic behaviour sleepless nights abrupt weight gain etc are inevitable part of a woman's life. As women age they move close to menopause a phase that marks the end of their menstrual cycle. And the main reason behind these physical and mental changes is the altering levels of female reproductive hormones: estrogen and progesterone. Although menopause is a normal stage of life it affects every woman in a different manner. On an average menopause sets in at the age of 51 but a few women can also experience premature menopause at the age of 40 which may worsen