For Women and Men

The very essence of an organism is that individual cells and groups of distinct types of cells interact with others for the benefit of the whole.

It's rather like civilization.
And hormones are how the rules of behavior are passed around.

A hormone is a substance which is produced by one organ, gland or type of tissue in an organism (plant or animal) and is then carried by the circulatory system to other parts of the organism, where the hormone causes a change in the way the organism functions...makes it sleepy, excited, inflames an area, makes the organism want to mate...virtually the whole range of physiological changes any organism goes through is modulated by hormones.

You have your thyroid-stimulating hormone, your follicle-stimulating hormone, your growth hormone, your insulin, your melatonin, dopamine, somatostatin, oxytocin, prolactin, the androgens - most notably testosterone, and the estrogens. And there are many more.

If one's body stops producing a hormone, or produces a hormone in below-optimum quantity, there will be symptoms.

Hormone replacement therapy can moderate or eliminate the symptoms, but is not without risk.

Hormone Replacement Therapy for Women

Hormone Replacement Therapy for Men