Biosimilars are biologic medical products that are almost identical copies of an original product that is manufactured by a different company. They are officially approved versions of original "innovator" products and can be manufactured when the original products patent expires. Biosimilars have a structure that is highly similar to, but not exactly the same as, a brand name biologic. They are made from the same types of sources (e.g., living cells or microorganisms) and are just as safe and effective as their reference products. Biosimilars undergo extensive analysis to confirm they have the same characteristics as the reference biologics. The U.S. Food and Drug Administration (FDA) has specific standards for biosimilars that must be met, and biosimilars must be shown to be as close to identical to the parent innovator biologic product based on data compiled through clinical, animal, analytical studies, and conformational status. Biosimilars are used for the treatment of many chronic and severe conditions, including chronic skin diseases, chronic bowel diseases, diabetes, macular degeneration, and arthritis. Biosimilars are as safe and effective as the original biologic, and both are rigorously and thoroughly evaluated by the FDA before approval. Biosimilars may cost less than the original biologics because manufacturers rely on the FDAs finding that the original biologics are safe and effective.