(Redirected from Low T)

Hypogonadism means diminished functional activity of the gonads—the testes or the ovaries—that may result in diminished production of sex hormones.

Other namesInterrupted stage 1 puberty

Low androgen (e.g., testosterone) levels are referred to as hypoandrogenism and low estrogen (e.g., estradiol) as hypoestrogenism. These are responsible for the observed signs and symptoms. Hypogonadism can decrease other hormones secreted by the gonads including progesterone, DHEA, anti-Müllerian hormone, activin, and inhibin. Sperm development (spermatogenesis) and release of the egg from the ovaries (ovulation) may be impaired by hypogonadism, which, depending on the degree of severity, may result in partial or complete infertility.

In January 2020, the American College of Physicians issued clinical guidelines for testosterone treatment in adult men with age-related low levels of testosterone. The guidelines are supported by the American Academy of Family Physicians. The guidelines include patient discussions regarding testosterone treatment for sexual dysfunction; annual patient evaluation regarding possible notable improvement and, if none, to discontinue testosterone treatment; physicians should consider intramuscular treatments, rather than transdermal treatments, due to costs and since the effectiveness and harm of either method is similar; and, testosterone treatment for reasons other than possible improvement of sexual dysfunction may not be recommended.[1][2]


Deficiency of sex hormones can result in defective primary or secondary sexual development, or withdrawal effects (e.g., premature menopause) in adults. Defective egg or sperm development results in infertility. The term hypogonadism usually means permanent rather than transient or reversible defects, and usually implies deficiency of reproductive hormones, with or without fertility defects. The term is less commonly used for infertility without hormone deficiency. There are many possible types of hypogonadism and several ways to categorize them. Hypogonadism is also categorized by endocrinologists by the level of the reproductive system that is defective. Physicians measure gonadotropins (LH and FSH) to distinguish primary from secondary hypogonadism. In primary hypogonadism the LH and/or FSH are usually elevated, meaning the problem is in the testicles (hyper-gonatropic hypogonadism); whereas in secondary hypogonadism, both are normal or low, suggesting the problem is in the brain (hypo-gonatropic hypogonadism).[citation needed]

Affected systemEdit

Primary or secondaryEdit

Congenital vs. acquiredEdit

Hormones vs. fertilityEdit

Hypogonadism can involve just hormone production or just fertility, but most commonly involves both.[citation needed]

  • Examples of hypogonadism that affect hormone production more than fertility are hypopituitarism and Kallmann syndrome; in both cases, fertility is reduced until hormones are replaced but can be achieved solely with hormone replacement.
  • Examples of hypogonadism that affect fertility more than hormone production are Klinefelter syndrome and Kartagener syndrome.


Hypogonadism can occur in other conditions, like Prader–Willi syndrome.[citation needed]

Signs and symptomsEdit

Women with hypogonadism do not begin menstruating and it may affect their height and breast development. Onset in women after puberty causes cessation of menstruation, lowered libido, loss of body hair, and hot flashes. In men, it causes impaired muscle and body hair development, gynecomastia, decreased height, erectile dysfunction, and sexual difficulties. If hypogonadism is caused by a disorder of the central nervous system (e.g., a brain tumor), then this is known as central hypogonadism. Signs and symptoms of central hypogonadism may involve headaches, impaired vision, double vision, milky discharge from the breast, and symptoms caused by other hormone problems.[9]

Hypogonadotrophic hypogonadismEdit

The symptoms of hypogonadotrophic hypogonadism, a subtype of hypogonadism, include late, incomplete or lack of development at puberty, and sometimes short stature or the inability to smell; in females, a lack of breasts and menstrual periods, and in males a lack of sexual development, e.g., facial hair, penis and testes enlargement, deepening voice.[citation needed]



Low testosterone can be identified through a simple blood test performed by a laboratory, ordered by a health care provider. Blood for the test must be taken in the morning hours, when levels are highest, as levels can drop by as much as 13% during the day and all normal reference ranges are based on morning levels.[10] However, low testosterone in the absence of any symptoms does not clearly need to be treated.[citation needed]

Normal total testosterone levels depend on the man's age but generally range from 240 to 950 ng/dL (nanograms per deciliter) or 8.3-32.9 nmol/L (nanomoles per liter).[11] According to American Urological Association, the diagnosis of low testosterone can be supported when the total testosterone level is below 300 ng/dl.[12] Some men with normal total testosterone have low free or bioavailable testosterone levels which could still account for their symptoms. Men with low serum testosterone levels should have other hormones checked, particularly luteinizing hormone to help determine why their testosterone levels are low and help choose the most appropriate treatment (most notably, testosterone is usually not appropriate for secondary or tertiary forms of male hypogonadism, in which the LH levels are usually reduced).[citation needed]

Treatment is often prescribed for total testosterone levels below 230 ng/dL with symptoms.[13] If the serum total testosterone level is between 230 and 350 ng/dL, free or bioavailable testosterone should be checked as they are frequently low when the total is marginal.

The standard range given is based on widely varying ages and, given that testosterone levels naturally decrease as humans age, age-group specific averages should be taken into consideration when discussing treatment between doctor and patient.[14] In men, testosterone falls approximately 1 to 3 percent each year.[15]

Blood testing

A position statement by the Endocrine Society expressed dissatisfaction with most assays for total, free, and bioavailable testosterone.[16] In particular, research has questioned the validity of commonly administered assays of free testosterone by radioimmunoassay.[16] The free androgen index, essentially a calculation based on total testosterone and sex hormone-binding globulin levels, has been found to be the worst predictor of free testosterone levels and should not be used.[17] Measurement by equilibrium dialysis or mass spectroscopy is generally required for accurate results, particularly for free testosterone which is normally present in very small concentrations.[citation needed]


Testing serum LH and FSH levels are often used to assess hypogonadism in women, particularly when menopause is believed to be happening. These levels change during a woman's normal menstrual cycle, so the history of having ceased menstruation coupled with high levels aids the diagnosis of being menopausal. Commonly, the post-menopausal woman is not called hypogonadal if she is of typical menopausal age. Contrast with a young woman or teen, who would have hypogonadism rather than menopause. This is because hypogonadism is an abnormality, whereas menopause is a normal change in hormone levels. In any case, the LH and FSH levels will rise in cases of primary hypogonadism or menopause, while they will be low in women with secondary or tertiary hypogonadism.[18]

Hypogonadism is often discovered during evaluation of delayed puberty, but ordinary delay, which eventually results in normal pubertal development, wherein reproductive function is termed constitutional delay. It may be discovered during an infertility evaluation in either men or women.[19]


Screening males who do not have symptoms for hypogonadism is not recommended as of 2018.[20]


Male primary or hypergonadotropic hypogonadism is often treated with testosterone replacement therapy if they are not trying to conceive.[13] Adverse effects of testosterone replacement therapy include increased cardiovascular events (including strokes and heart attacks) and death.[21] The Food and Drug Administration (FDA) stated in 2015 that neither the benefits nor the safety of testosterone have been established for low testosterone levels due to aging.[22][23] The FDA has required that testosterone pharmaceutical labels include warning information about the possibility of an increased risk of heart attacks and stroke.[22][23]

While historically, men with prostate cancer risk were warned against testosterone therapy, that has shown to be a myth.[24]

Other side effects can include an elevation of the hematocrit to levels that require blood withdrawal (phlebotomy) to prevent complications from excessively thick blood. Gynecomastia (growth of breasts in men) sometimes occurs. Finally, some physicians worry that obstructive sleep apnea may worsen with testosterone therapy, and should be monitored.[25]

Another treatment for hypogonadism is human chorionic gonadotropin (hCG).[26] This stimulates the LH receptor, thereby promoting testosterone synthesis. This will not be effective in men who simply cannot make testosterone anymore (primary hypogonadism) and the failure of hCG therapy is further support for the existence of true testicular failure in a patient. It is particularly indicated in men with hypogonadism who wish to retain their fertility, as it does not suppress spermatogenesis as testosterone replacement therapy does.[citation needed]

For both men and women, an alternative to testosterone replacement is low-dose clomifene treatment, which can stimulate the body to naturally increase hormone levels while avoiding infertility and other side effects that can result from direct hormone replacement therapy.[27] Clomifene blocks estrogen from binding to some estrogen receptors in the hypothalamus, thereby causing an increased release of gonadotropin-releasing hormone and subsequently LH from the pituitary. Clomifene is a selective estrogen receptor modulator (SERM). Generally, clomifene does not have adverse effects at the doses used for this purpose. Clomifene at much higher doses is used to induce ovulation and has significant adverse effects in such a setting.[citation needed]

Androgen replacement therapy formulations and dosages used in men
Route Medication Major brand names Form Dosage
Oral Testosteronea Tablet 400–800 mg/day (in divided doses)
Testosterone undecanoate Andriol, Jatenzo Capsule 40–80 mg/2–4x day (with meals)
Methyltestosteroneb Android, Metandren, Testred Tablet 10–50 mg/day
Fluoxymesteroneb Halotestin, Ora-Testryl, Ultandren Tablet 5–20 mg/day
Metandienoneb Dianabol Tablet 5–15 mg/day
Mesteroloneb Proviron Tablet 25–150 mg/day
Buccal Testosterone Striant Tablet 30 mg 2x/day
Methyltestosteroneb Metandren, Oreton Methyl Tablet 5–25 mg/day
Sublingual Testosteroneb Testoral Tablet 5–10 mg 1–4x/day
Methyltestosteroneb Metandren, Oreton Methyl Tablet 10–30 mg/day
Intranasal Testosterone Natesto Nasal spray 11 mg 3x/day
Transdermal Testosterone AndroGel, Testim, TestoGel Gel 25–125 mg/day
Androderm, AndroPatch, TestoPatch Non-scrotal patch 2.5–15 mg/day
Testoderm Scrotal patch 4–6 mg/day
Axiron Axillary solution 30–120 mg/day
Androstanolone (DHT) Andractim Gel 100–250 mg/day
Rectal Testosterone Rektandron, Testosteronb Suppository 40 mg 2–3x/day
Injection (IM or SC) Testosterone Andronaq, Sterotate, Virosterone Aqueous suspension 10–50 mg 2–3x/week
Testosterone propionateb Testoviron Oil solution 10–50 mg 2–3x/week
Testosterone enanthate Delatestryl Oil solution 50–250 mg 1x/1–4 weeks
Xyosted Auto-injector 50–100 mg 1x/week
Testosterone cypionate Depo-Testosterone Oil solution 50–250 mg 1x/1–4 weeks
Testosterone isobutyrate Agovirin Depot Aqueous suspension 50–100 mg 1x/1–2 weeks
Testosterone phenylacetateb Perandren, Androject Oil solution 50–200 mg 1x/3–5 weeks
Mixed testosterone esters Sustanon 100, Sustanon 250 Oil solution 50–250 mg 1x/2–4 weeks
Testosterone undecanoate Aveed, Nebido Oil solution 750–1,000 mg 1x/10–14 weeks
Testosterone buciclatea Aqueous suspension 600–1,000 mg 1x/12–20 weeks
Implant Testosterone Testopel Pellet 150–1,200 mg/3–6 months
Notes: Men produce about 3 to 11 mg testosterone per day (mean 7 mg/day in young men). Footnotes: a = Never marketed. b = No longer used and/or no longer marketed. Sources: See template.

See alsoEdit


  1. ^ Qaseem, Amir; et al. (6 January 2020). "Testosterone Treatment in Adult Men With Age-Related Low Testosterone: A Clinical Guideline From the American College of Physicians". Annals of Internal Medicine. 172 (2): 126–133. doi:10.7326/M19-0882. PMID 31905405. Retrieved 7 January 2020.
  2. ^ Parry, Nicola M. (7 January 2020). "New Guideline for Testosterone Treatment in Men With 'Low T'". Medscape.com. Retrieved 7 January 2020.
  3. ^ "Hypogonadism". The Lecturio Medical Concept Library. Retrieved 26 July 2021.
  4. ^ "Hypogonadism". The Lecturio Medical Concept Library. Retrieved 26 July 2021.
  5. ^ "Hypogonadism". The Lecturio Medical Concept Library. Retrieved 26 July 2021.
  6. ^ MedlinePlus Encyclopedia: Hypogonadotropic hypogonadism
  7. ^ "Hypogonadism". The Lecturio Medical Concept Library. Retrieved 26 July 2021.
  8. ^ "Symptoms". irondisorders.org. Retrieved 21 March 2018.
  9. ^ MedlinePlus Encyclopedia: Hypogonadism
  10. ^ Crawford ED, Barqawi AB, O'Donnell C, Morgentaler A (September 2007). "The association of time of day and serum testosterone concentration in a large screening population". BJU International. 100 (3): 509–13. doi:10.1111/j.1464-410X.2007.07022.x. PMID 17555474. S2CID 23740125. Lay summaryUroToday (12 July 2007).
  11. ^ "Testosterone, Total, Bioavailable, and Free, Serum". Mayo Medical Laboratories. Mayo Clinic. 2016. Retrieved 19 Dec 2016.
  12. ^ Mulhall, John P.; Trost, Landon W.; Brannigan, Robert E.; Kurtz, Emily G.; Redmon, J. Bruce; Chiles, Kelly A.; Lightner, Deborah J.; Miner, Martin M.; Murad, M. Hassan (August 2018). "Evaluation and Management of Testosterone Deficiency: AUA Guideline". Journal of Urology. 200 (2): 423–432. doi:10.1016/j.juro.2018.03.115. ISSN 0022-5347. PMID 29601923.
  13. ^ a b Nieschlag E, Swerdloff R, Behre HM, Gooren LJ, Kaufman JM, Legros JJ, Lunenfeld B, Morley JE, Schulman C, Wang C, Weidner W, Wu FC (2006). "Investigation, treatment, and monitoring of late-onset hypogonadism in males: ISA, ISSAM, and EAU recommendations". Journal of Andrology. 27 (2): 135–7. doi:10.2164/jandrol.05047. PMID 16474020.
  14. ^ Hildebrandt, Brian. "Normal Testosterone Levels In Men - Average Ranges By Age". mens-hormonal-health.com. Retrieved 21 March 2018.
  15. ^ School, Florence Comite, MD; Foreword by Abraham Morgentaler, MD associate clinical professor of urology, Harvard Medical (2013). Keep it up : the power of precision medicine to conquer low T and revitalize your life. Rodale Books. p. 14. ISBN 978-1609611019.
  16. ^ a b Rosner W, Auchus RJ, Azziz R, Sluss PM, Raff H (February 2007). "Position statement: Utility, limitations, and pitfalls in measuring testosterone: an Endocrine Society position statement". The Journal of Clinical Endocrinology and Metabolism. 92 (2): 405–13. doi:10.1210/jc.2006-1864. PMID 17090633.
  17. ^ Morris PD, Malkin CJ, Channer KS, Jones TH (August 2004). "A mathematical comparison of techniques to predict biologically available testosterone in a cohort of 1072 men". European Journal of Endocrinology. 151 (2): 241–9. doi:10.1530/eje.0.1510241. PMID 15296480.
  18. ^ Carnegie C (2004). "Diagnosis of Hypogonadism: Clinical Assessments and Laboratory Tests". Reviews in Urology. 6 (Suppl 6): S3–S8. PMC 1472884. PMID 16985909.
  19. ^ Carnegie C (2004). "Diagnosis of Hypogonadism: Clinical Assessments and Laboratory Tests". Reviews in Urology. 6 (Suppl 6): S3–S8. PMC 1472884. PMID 16985909.
  20. ^ Bhasin S, Brito JP, Cunningham GR, Hayes FJ, Hodis HN, Matsumoto AM, Snyder PJ, Swerdloff RS, Wu FC, Yialamas MA (May 2018). "Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline". The Journal of Clinical Endocrinology and Metabolism. 103 (5): 1715–1744. doi:10.1210/jc.2018-00229. PMID 29562364.
  21. ^ Finkle WD, Greenland S, Ridgeway GK, Adams JL, Frasco MA, Cook MB, Fraumeni JF, Hoover RN (January 2014). "Increased risk of non-fatal myocardial infarction following testosterone therapy prescription in men". PLOS ONE. 9 (1): e85805. Bibcode:2014PLoSO...985805F. doi:10.1371/journal.pone.0085805. PMC 3905977. PMID 24489673.
  22. ^ a b Staff (3 March 2015). "Testosterone Products: Drug Safety Communication - FDA Cautions About Using Testosterone Products for Low Testosterone Due to Aging; Requires Labeling Change to Inform of Possible Increased Risk of Heart Attack And Stroke". FDA. Retrieved 5 March 2015.
  23. ^ a b Tavernise, Sabrina (March 3, 2015). "Drugs Using Testosterone Will Label Heart Risks". New York Times. Retrieved March 19, 2015.
  24. ^ Morgentaler A (November 2006). "Testosterone and prostate cancer: an historical perspective on a modern myth". European Urology. 50 (5): 935–9. doi:10.1016/j.eururo.2006.06.034. PMID 16875775.
  25. ^ Matsumoto AM, Sandblom RE, Schoene RB, Lee KA, Giblin EC, Pierson DJ, Bremner WJ (June 1985). "Testosterone replacement in hypogonadal men: effects on obstructive sleep apnoea, respiratory drives, and sleep". Clinical Endocrinology. 22 (6): 713–21. doi:10.1111/j.1365-2265.1985.tb00161.x. hdl:1773/4497. PMID 4017261. S2CID 1790630.
  26. ^ Chudnovsky A, Niederberger CS (2007). "Gonadotropin therapy for infertile men with hypogonadotropic hypogonadism". Journal of Andrology. 28 (5): 644–6. doi:10.2164/jandrol.107.003400. PMID 17522414.
  27. ^ Whitten SJ, Nangia AK, Kolettis PN (December 2006). "Select patients with hypogonadotropic hypogonadism may respond to treatment with clomiphene citrate". Fertility and Sterility. 86 (6): 1664–8. doi:10.1016/j.fertnstert.2006.05.042. PMID 17007848.

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