TLDR Testosterone boosts red blood cell production and changes iron metabolism without needing dihydrotestosterone.
The study investigated whether the conversion of testosterone (T) to dihydrotestosterone (DHT) via type II 5α-reductase is necessary for testosterone's effects on red blood cell (RBC) production and iron metabolism in older hypogonadal men. Sixty men aged 60 and above with low testosterone levels were treated with testosterone-enanthate (TE) and finasteride or placebo over 12 months. TE increased RBC count by 9%, hematocrit by 4%, and hemoglobin by 8%, while reducing serum hepcidin by 57% and serum ferritin by 32%, without affecting iron, transferrin, or transferrin saturation. These changes occurred mostly within the first 3 months and were not significantly altered by finasteride. The study concluded that TE stimulates erythropoiesis and alters iron homeostasis independently of DHT, indicating that elevated DHT is not required for these androgenic effects.
124 citations
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March 2012 in “JAMA” Testosterone's muscle-building effects do not require its conversion to DHT.
35 citations
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October 2011 in “Medicine and science in sports and exercise” Muscles can make their own androgens, which may help muscle growth.
42 citations
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May 2007 in “Endocrinology and metabolism/American journal of physiology: endocrinology and metabolism” Testosterone can build muscle and bone without enlarging the prostate when a specific enzyme is blocked.
506 citations
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March 2005 in “The Journal of Clinical Endocrinology and Metabolism” Testosterone therapy improves physical function, strength, and body composition in older men with low testosterone levels.
417 citations
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February 2004 in “The Journal of Clinical Endocrinology and Metabolism” Testosterone therapy increases bone density in older men with low testosterone levels.
115 citations
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March 2001 in “Baillière's best practice and research in clinical endocrinology and metabolism/Baillière's best practice & research. Clinical endocrinology & metabolism” Key enzymes control androgen levels, affecting hormone activity and potential treatments.
June 2023 in “Clinica Chimica Acta” Finasteride and dutasteride effectively reduce DHT in hair, which may help evaluate their treatment success for hair loss.
65 citations
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October 1999 in “Journal of The American Academy of Dermatology” Finasteride effectively reduces hair loss by decreasing androgen levels.
59 citations
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September 1994 in “The Journal of Clinical Endocrinology and Metabolism” Finasteride reduces scalp DHT levels, potentially treating male pattern baldness.
