Hormone Basics

Hormones are chemical messengers produced by glands in the endocrine system. They travel through the bloodstream to tissues and organs, regulating key processes such as growth, metabolism, reproduction, mood, and the maintenance of homeostasis.

Key facts about hormones:

• Many functions: Different hormones — such as estrogen, progesterone, testosterone, thyroid hormones, cortisol, growth factors — serve very different roles: from reproductive regulation to bone maintenance, metabolism, cardiovascular health, cognition, mood, and beyond.

• Regulatory complexity: Hormone levels and their effects are regulated by feedback loops (e.g., hypothalamic-pituitary axes), receptor sensitivity, rate of hormone production, conversion between different hormones, and tissue-specific responses.

• Life-stage changes: Hormone production and balance change over a lifetime. Major transitions — such as puberty, pregnancy, menopause (in people assigned female at birth), or age-related hormone decline (in people assigned male at birth) — often lead to noticeable shifts in health, mood, metabolism, and quality of life.

Because of these broad effects, hormone imbalances — whether from natural aging, illness, surgical removal of hormone-producing organs, or other causes — can significantly impact health. In many cases, medically supervised hormone therapy can restore balance, alleviate symptoms, and improve quality of life.

But important caveats apply: different hormones and different formulations have different benefits and risks; what works for one person may not be appropriate for another. That’s why hormone therapy should always be individualized, and discussed with a qualified healthcare provider.