The naturally occurring terpenoid lipids in animals, plants, and fungi, Steroids are often classified into animal steroids, insect steroids, ecdysteroids, vertebrate steroids, steroid hormones, plant steroids, and fungus steroids. Steroids are found in human beings in the form of steroid hormones, which are further classified as sex steroids, corticosteroids, and anabolic steroids.
Sex steroids are the sex hormones that play important role in creating sex differences and reproduction in humans. They include estrogen or oestrogen, progesterone and testosterone. Oestrogen and progesterone are produced primarily in the ovary and placenta during pregnancy and testosterone is mainly produced in the male testes. Corticosteroids including glucocorticoids and mineralocorticoids are responsible in regulating many aspects of metabolism and immune function.
Anabolic steroids are the most well known steroids. Occurring naturally in human bodies, anabolic steroids play key role in the growth genitals, body muscles, and bones. However, anabolic steroids are also produced synthetically. The synthetically produced anabolic steroids are produced as anabolic steroid drugs or medications.
Synthetically produced anabolic steroids are also known as anabolic-androgenic steroids or AAS. They are actually steroid hormones associated with the hormone testosterone, a strong androgenic hormone produced chiefly by the testes, and it is responsible for the development of male secondary sex characteristics. The main function of anabolic steroids is protein synthesis within cells, which helps in building up of cellular tissue (anabolism), especially in muscles. These steroids also play androgenic and virilizing role. They help in the development and maintenance of masculine features, such as the growth of the vocal cords and body hair.
Thus, anabolic steroids are medically used to enhance bone growth and appetite, to stimulate male puberty, and to treat many chronic wasting diseases, such as AIDS and cancer. They are often used to increase muscle mass and physical strength. However, the synthetic anabolic substances are widely used as performance enhancing drugs. They are extensively used, abused, overused in sports and bodybuilding to increase strength or physique.

However, there are several serious health risks associated with excessive and long term use of anabolic steroids. Some of the side effects linked with anabolic steroid use include adverse changes in cholesterol levels – increase in LDL (Low Density Lipoprotein) and decrease in HDL (High Density Lipoprotein), severe acne, hypertension, liver damage, and deadly changes in the structure of the left ventricle of the heart.