Steroids are types of hormones; but not all hormones are steroids. Because steroids are hormones, they act as chemical messengers directing the [Page 1303]activities of the body. Steroid hormones are target specific, meaning that they can start or stop the processes of the organs they target. There are two basic classes of steroids: (1) fatty acid based, which are the building block of lipids, and (2) amino acid based, which are the building block of proteins. Both types of steroid hormones are made of the elements carbon, hydrogen, and oxygen chemically combined; therefore, they are organic macromolecules (large molecules). Lipid-based steroid hormones are essential for the health and well-being of humankind as lipids contain the greatest amount of stored energy. When energy levels are low, ...