Testosterone is an essential part of Natural Hormone Replacement Programs. It is the primary male hormone. Testosterone is very important for strength, energy and libido. It is an important male hormone which is secreted by the testes and adrenal glands.

Testosterone improves a man’s libido and works synergistically to enhance the functions of the body's other hormones. When men notice their skin is not quite as tight as it used to be, this is a sure sign of declining Testosterone. Skin tone is affected as the muscles beneath lose their firmness, strength and size.

Testosterone is also essential in strengthening bones in preventing osteoporosis. Like other hormones, testosterone levels peak at about the age of twenty-five and then slowly decline. Symptoms appear as a gradual decrease in energy and stamina, thinning bones and muscles, increased visceral fat, depression, and impaired sexual function.

Testosterone deficiency has also been linked to hypertension, obesity and increased risk of heart disease. Stress level may also play a role in declining testosterone levels.

Dehydroepiandrosterone, a steroid hormone is a natural substance produced in the adrenal glands, gonads and brain. The mean concentration of DHEA in serum decreases progressively from a peak at age 25 to less than 20% of that peak before the age of 70. Further serum levels are typically low in those with chronic diseases, such as cancer and AIDS, and heart disease as well.

DHEA is metabolized in the adrenal glands to other substances including testosterone.  Some of the reported effects may be due to the fact that is metabolized to androgens and estrogens. The observed benefits of DHEA in men with Low-T, for example may be accounted for by this androgenic activity. DHEA is absorbed from the small intestine and transported to the liver where it is metabolized and distributed to the various tissues where metabolites are synthesized.

Thyroid hormone is a metabolic hormone secreted by the thyroid gland. There are two types of thyroid hormones, Thyroxine (T4) and Triiodothyronine (T3). T4 is inactive and kept in reserve, T3 is the active hormone. Thyroid hormones control the growth differentiation and metabolism of each cell in the body. They also control how fast our body uses the fuel that we consume, particularly carbohydrates and fat. This in turn helps to regulate our temperature and body fat percentage. The thyroid hormones T3 and T4 are produced in the thyroid gland.  About 80% of the thyroid hormones we produce is T4, the inactive thyroid hormone that is typically held in reserve by the body. T3 makes up only 20% of the thyroid hormone, but is about four times more potent than T4 and is the active hormone that the body uses to function. T4 is converted into T3 when thyroid hormone is needed.

The release of the thyroid hormones is controlled by the thyroid-stimulating hormone (TSH), which is produced in the pituitary gland. Low circulating levels of thyroid hormone are detected by the hypothalamus, which then instructs the pituitary gland to release TSH. When sufficient amounts are released the hypothalamus communicates with the pituitary to stop or slow down. Because of this complicated feedback loop, high levels of TSH in the blood often means the pituitary is trying to stimulate production of the thyroid hormone but the thyroid gland is not responding. This condition is known as hypothroidism.