The hormones TSH (Thyroid Stimulating Hormone), Testosterone, and Cortisol are all key players for a healthy metabolism. If the thyroid gland is not producing adequate hormones, it is near impossible for adequate energy production to be present in the cells. Testosterone is also essential due to its effects on increasing lean body mass and increasing basal metabolic rate.
Cortisol is also an important hormone that must not be too high since it has been shown to slow down metabolism by decreasing lean muscle mass and increasing blood sugar levels. By evaluating these three hormones at once, clinicians can get a good picture of how well the body's metabolism as a whole is functioning. This is ideal for individuals struggling with weight loss plateau's and fatigue.
Metabolism is the process by which the body converts the foods we eat and fluids we drink into energy. This happens on a cellular level via the release of hormones and other biochemical catalysts, and is essential for life-sustaining functions. Thyroid hormones function like a thermostat in the body, regulating when to increase energy production or decrease energy production based on basal body "temperatures," or efficiency of ATP production (the currency of the cell). This process is controlled by complex signaling of TSH (Thyroid Stimulating Hormone) from the hypothalamus and pituitary glands in the brain. In addition to supporting healthy libido, Testosterone hormone affects fat metabolism and regulates basal metabolism. Research shows that optimal levels of testosterone are correlated with a higher percentage of lean body mass (muscle) and lower body fat percentages both in storage forms (belly fat) and circulating fats (cholesterol).
This fine-tuned orchestra of metabolism is disrupted when the hormone Cortisol (a glucocorticoid) is released by the adrenal glands, usually in response to stress. Elevated cortisol levels function to slow down metabolism to conserve energy for vital "fight or flight" functions such as blood pressure or heart rate. Elevated cortisol also slows down immune function and works against insulin to keep circulating levels of glucose in the blood stream longer for perceived "fight or flight" actions.