There isn't total agreement on the threshold of testosterone value below which a man would be considered hypogonadal. (Currently there are no standards as to when to treat women.) Testosterone can be measured as "free" (that is, bioavailable and unbound) or more commonly, "total" (including the percentage which is chemically bound and unavailable). In the United States, male total testosterone levels below 300 to 400 ng/dl from a morning sample[vague] are generally considered low.[citation needed] However these numbers are typically not age-adjusted, but based on an average of a test group which includes elderly males with low testosterone levels.[citation needed] Therefore a value of 300 ng/dl might be normal for a 65-year-old male, but not normal for a 30-year-old.[citation needed] Identification of inadequate testosterone in an aging male by symptoms alone can be difficult. The signs and symptoms are non-specific, and might be confused with normal aging characteristics, such as loss of muscle mass and bone density, decreased physical endurance, decreased memory ability[citation needed] and loss of libido.
Replacement therapy can take the form of injectable depots, transdermal patches and gels, subcutaneous pellets and oral therapy. Adverse effects of testosterone supplementation include minor side effects such as acne and oily skin, and more significant complications such as increased hematocrit which can require venipuncture in order to treat, exacerbation of sleep apnea and acceleration of pre-existing prostate cancer growth. Exogenous testosterone also causes suppression of spermatogenesis and can lead to infertility.[18] It is recommended that physicians screen for prostate cancer with a digital rectal exam and PSA (prostate specific antigen) level prior to initiating therapy, and monitor hematocrit and PSA levels closely during therapy.
[edit] Benefits
Appropriate testosterone therapy can prevent or reduce the likelihood of osteoporosis, type 2 diabetes, cardio-vascular disease (CVD), obesity, depression and anxiety and the statistical risk of early mortality. Low testosterone also brings with it an increased risk for the development of Alzheimer’s Disease (Pike et al, 2006, Rosario 2004).
A small trial in 2005 showed mixed results.[19]
Large scale trials to assess the efficiency and long-term safety of testosterone are still lacking.[20]
[edit] See also
[edit] Notes
- ^ James McBride Dabbs, 2000
- ^ Gallagher and Koch, 1929.
- ^ Hoberman and Yesalis 1995, Freeman et al. 2001.
- ^ Kenyon et al. 1940.
- ^ Schwarz et al. 1999.
- ^ deKruif, 1945.
- ^ Bhasin S, Storer TW, Berman N, et al
- ^ Solms and Turnbull 2002.
- ^ Bhasin S, Storer TW, Berman N, et al
- ^ e.g., Moffat et al, 2005; Hogervorst et al 2005.
- ^ e.g., Moffat and Hampson, 1996.
- ^ "Andriol". Food and Drug Administration.
- ^ "Striant". Food and Drug Administration.
- ^ "Androgel". Food and Drug Administration. and "Testim". Food and Drug Administration.
- ^ a b Davis SR, Moreau M, Kroll R, et al. (2008). "Testosterone for low libido in postmenopausal women not taking estrogen". N Engl J Med 359 (19): 2005–2017, http://content.nejm.org/cgi/content/short/359/19/2005?query=TOC.
- ^ "Anabolic Steroid Control Act". United States Sentencing Commission (1990).
- ^ "Medical guidelines for clinical practice for the evaluation and treatment of male sexual dysfunction". American association of clinical endocrinologists.
- ^ World Health Organisation (1990), The Lancet.
- ^ http://www.ncbi.nlm.nih.gov/pubmed/18167405 "Effect of testosterone supplementation on functional mobility, cognition, and other parameters in older men: a randomized controlled trial."
- ^ http://www.endocrinetoday.com/view.aspx?rid=29171 "Testosterone treatment in aging men"
[edit] References
- Ajayi AAL, Mathur R, Halushka PV. Testosterone increases platelet TXA2 receptor density and aggregation responses (1995). Circulation 91 : 2742-7.
- Ajayi AAL, Halushka PV. Castration reduces platelet TXA2 receptor density and aggregability (2005). QJM 98 : 349-57.
- Bhasin S, Storer TW, Berman N, et al (1996). "The effects of supraphysiologic doses of testosterone on muscle size and strength in normal men". N. Engl. J. Med. 335 (1): 1–7. doi:. PMID 8637535.
- E.R. Freeman, D.A. Bloom, and E.J. McGuire (2001). "A brief history of testosterone". Journal of Urology 165: 371–373. doi:. PMID 11176375.
- J.M. Hoberman and C.E. Yesalis (1995). "The history of synthetic testosterone". Scientific American 272: 76–81. PMID 7817189.
- P.R. Larsen et al. (2003). Williams textbook of endocrinology (10th edition ed.), Saunders. ISBN 978-0-7216-9184-8. OCLC 48942603 50841393. (Seventh edition by J.D. Wilson and R.H. Williams, 1985, ISBN 072161082X.)
- S.D. Moffat and E. Hampson (1996). "A curvilinear relationship between testosterone and spatial cognition in humans: Possible influence of hand preference". Psychoneuroendocrinology 21 (3): 323–337. doi:.
- S.D. Moffat, A.B. Zonderman, E.J. Metter et al. (2004). "Free testosterone and risk for Alzheimer's disease in older men". Neurology 62: 188–193.
- M. Parssinen, U. Kujala, E. Vartiainen, et al. (2000). "Increased premature mortality of competitive powerlifters suspected to have used anabolic agents". International Journal of Sports Medicine 21: 225–227. doi:.
- S. Schwarz, D. Onken, and A. Schubert (1999). "The steroid story of Jenapharm: From the late 1940s to the early 1970s". Steroids 64: 439–445. doi:, http://www.ingentaconnect.com/content/els/0039128x/1999/00000064/00000007/art00003.
- M. Solms and O. Turnbull (2002). The brain and the inner world, Other Press, New York. ISBN 978-1590510179. OCLC 48761737 59373319.
- World Health Organization Task Force on methods for the regulation of male fertility (1990). "Contraceptive efficacy of testosterone-induced azoospermia in normal men". Lancet 336: 955–959. doi:. PMID 1977002.
[edit] External links
- NIST entry for Testosterone
- NIST results of search for Testosterone (Shows androstenone.)
- Results of research on the efficacy of differing body locations for the absorption of topical testosterone creams
- "Calls for testosterone trials in CHD "
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