Thyroid hormones activate over 100 cellular body enzymes which assure the multitude of functions. Among them are: proper energy production and metabolism, tissue oxygenation, synthesis of protein and breakdown of fat and carbohydrates, normal mineral exchange within cells, stimulation of insulin production and other functions. Since all of the body cells are dependent on these properties, most of the major organs and tissues contain within their cells, receptors for thyroid hormones. Brain, heart, lungs, adrenals, gastrointestinal organs, testes, ovaries, muscles and other tissues all owe much to thyroid hormones for their normal functioning. That is why the symptoms that are related to a malfunctioning thyroid system could be very diverse and virtually endless. They may include depression and anxiety, insomnia and fatigue, cardiovascular and weight problems, frequent infections or hypo and hyperglycemia, high cholesterol and sensitivity to cold, malabsorption resulting in dry skin, breaking nails and osteop orosis, numerous hormonal dysfunctions with low libido and infertility in both sexes or retarded growth in children and so on. In addition, the countless secondary effects of a sluggish thyroid system will arise, due to fluctuations in blood sugar or low body temperature or even body pH, which will all impair the function of multiple enzymes in the body.