Hypoandrogenism is caused primarily by either dysfunction, failure, or absence of the gonads (hypergonadotropic) or impairment of the hypothalamus or pituitary gland (hypogonadotropic), which in turn can be caused by a multitude of different stimuli, including genetic conditions (e.g., GnRH/gonadotropin insensitivity and enzymatic defects of steroidogenesis), tumors, trauma, surgery, autoimmunity, radiation, infections, toxins, drugs, and many others. Alternatively, it may be the result of conditions such as androgen insensitivity syndrome or hyperestrogenism. More simply, old age may also be a factor in the development of hypoandrogenism, as androgen levels decline with age.
Signs and symptoms 
Signs of hypoandrogenism in both sexes may include lowered levels of androgens such as testosterone and dihydrotestosterone, abnormally high or low levels of follicle-stimulating hormone and/or luteinizing hormone, and heightened or lowered levels of estrogens such as estradiol.
Symptoms of the condition in males consist of loss of libido, impotence, infertility, shrinkage of the testicles, penis, and prostate, diminished masculinization (e.g., decreased facial and body hair growth), low muscle mass, anxiety, depression, fatigue, hot flashes, insomnia, headaches, and osteoporosis. In addition, symptoms of hyperestrogenism, such as gynecomastia and feminization, may be concurrently present in males. In females, hypoandrogenism generally presents predominantly as psychological symptoms such as loss of libido, lowered mood, blunted motivation, flat affect, reduced energy, but may also present with other symptoms such as decreased pubic hair growth, vaginal vasocongestion (which can result in cramps), vasomotor symptoms (e.g., hot flashes and palpitations), insomnia, headaches, and reduced bone and muscle mass. Symptoms of hypoestrogenism may be present in both sexes in cases of severe androgen deficiency (as estrogens are synthesized from androgens).
Treatment may consist of hormone replacement therapy with androgens in either sex. Alternatively, gonadotropin-releasing hormone (GnRH)/GnRH agonists or gonadotropins may be given (in the case of hypogonadotropic hypoandrogenism).
See also 
- Jakiel G, Baran A (2005). "[Androgen deficiency in women]". Endokrynologia Polska (in Polish) 56 (6): 1016–20. PMID 16821229.
- Bachmann GA (April 2002). "The hypoandrogenic woman: pathophysiologic overview". Fertility and Sterility. 77 Suppl 4: S72–6. PMID 12007907.
- William J. Bremner (27 May 2003). Androgens in Health and Disease. Humana Press. pp. 365–379. ISBN 978-1-58829-029-8. Retrieved 11 June 2012.