I

Immune System

The complex network of specialized organs, glands, and cells that, when working properly, protect the body from pathogens such as viruses, bacteria, fungi, cancer cells, and atherosclerotic plaques. Specialized white blood cells (T-cells, B-cells) are the body's main defense against many pathogens. The immune system also includes the thymus gland, lymphatic system, spleen, and bone marrow.

Inositol

A vitamin that has a calming effect, helps reduce cholesterol, and facilitates hair growth.

Insulin

A protein hormone secreted by the pancreas that converts sugar (glucose) and other carbohydrates into energy.

Insulin-like Growth Factor (IGF)

Human Growth Hormone (HGH) stimulates production in the liver of IGF-1 (also called somatomedin-C) and other growth factors that profoundly influence the body. Anti-aging researchers are conducting intensive studies of IGF in conjunction with Hormone Replacement Therapies and related anti-aging programs.

International Units (IU)

An internationally accepted measure of potency (instead of weight or volume) that is used for measuring supplements such as Vitamin A, Vitamin E, etc.

Intramuscular

Administration of a medicine by injection in the muscle mass.

Intravenous (IV)

Administration of a medicine by injection in the body's circulatory system.

Iodine

Mineral that the body needs to promote the health of the thyroid gland.

Iron

Mineral that the body needs for the metabolism of B-complex vitamins and to prevent fatigue. Note: Excess iron may be a strong catalyst for free radical production and may contribute to plaque deposits in blood vessels.