• A hormone made mainly in the testes (part of the male reproductive system). It is needed to develop and maintain male sex characteristics, such as facial hair, deep voice, and muscle growth. Testosterone may also be made in the laboratory and is used to treat certain medical conditions.
  NCI Dictionary of Cancer Terms
  U.S. National Cancer Institute, 2021
• A male hormone that stimulates bone and muscle growth and sexual development in men; also produced in lesser amounts in women, promoting sex drive and muscle growth.
  Harvard Dictionary of Health Terms
  Harvard Medical Publishing, 2011
• A potent androgenic steroid and major product secreted by the LEYDIG CELLS of the TESTIS. Its production is stimulated by LUTEINIZING HORMONE from the PITUITARY GLAND. In turn, testosterone exerts feedback control of the pituitary LH and FSH secretion. Depending on the tissues, testosterone can be further converted to DIHYDROTESTOSTERONE or ESTRADIOL.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2025
• Major androgenic hormone produced by the Leydig cells of the testes.
  CRISP Thesaurus
  National Institutes of Health, 2006
• Testosterone, hormone produced by the male testis that is responsible for development of the male sex organs and masculine characteristics, including facial hair and deepening of the voice. Testosterone was isolated from testicular extracts in 1935. Its discovery followed that of an androgen (male...
  Encyclopedia Britannica
  Encyclopedia Britannica, Inc., 2025