Testosterone is a vital hormone that is responsible for the development of male sexual characteristics, such as muscle mass, bone density, and body hair. It is also essential for the maintenance of reproductive health and the regulation of sex drive in both men and women. However, low testosterone levels can lead to a range of negative health outcomes, including reduced muscle mass, decreased bone density, and an increased risk of chronic diseases such as diabetes and heart disease. (1)

One potential solution to low testosterone levels is through the use of vitamin D supplementation. (2) Vitamin D is a fat-soluble vitamin that is produced in the skin when exposed to sunlight. It is also found in some foods, such as fatty fish and egg yolks, and is often added to milk and other dairy products. (3) Vitamin D is essential for the absorption of calcium and the maintenance of bone health, but it also plays a critical role in the regulation of testosterone levels.

Research has shown that men with low levels of vitamin D also tend to have lower levels of testosterone. (4, 5) In fact, a study published in the journal Hormone and Metabolic Research found that men with low vitamin D levels were more likely to have low testosterone levels than men with adequate vitamin D levels. (6) The study also found that vitamin D supplementation improved testosterone levels in men with low vitamin D levels.

So, how does vitamin D mediate low testosterone? One theory is that vitamin D increases the production of luteinizing hormone (LH) in the pituitary gland. (7) LH is responsible for stimulating the production of testosterone in the testes. Thus, when vitamin D levels are low, LH production may also be low, leading to decreased testosterone production.

Another theory is that vitamin D may reduce the production of sex hormone-binding globulin (SHBG). (8) SHBG is a protein that binds to testosterone in the blood, reducing its availability for use by the body. When vitamin D levels are low, SHBG production may increase, leading to decreased free testosterone levels.

Overall, the research suggests that vitamin D may play a critical role in the regulation of testosterone levels in men. While more research is needed to fully understand the mechanisms involved, vitamin D supplementation may be a useful tool for men with low testosterone levels. If you are experiencing symptoms of low testosterone, such as decreased sex drive or muscle mass, talk to your healthcare provider about whether vitamin D supplementation may be right for you.

Resources:

1. Morales A, Bebb RA, Manjoo P, Assimakopoulos P, Axler J, Collier C, Elliott S, Goldenberg L, Gottesman I, Grober ED, Guyatt GH, Holmes DT, Lee JC; Canadian Men’s Health Foundation Multidisciplinary Guidelines Task Force on Testosterone Deficiency. Diagnosis and management of testosterone deficiency syndrome in men: clinical practice guideline. CMAJ. 2015 Dec 8;187(18):1369-1377. doi: 10.1503/cmaj.150033. Epub 2015 Oct 26. PMID: 26504097; PMCID: PMC4674408.
2. Pilz S, Frisch S, Koertke H, Kuhn J, Dreier J, Obermayer-Pietsch B, Wehr E, Zittermann A. Effect of vitamin D supplementation on testosterone levels in men. Horm Metab Res. 2011 Mar;43(3):223-5. doi: 10.1055/s-0030-1269854. Epub 2010 Dec 10. PMID: 21154195.
3. U.S. Department of Health and Human Services. (n.d.). Office of dietary supplements - vitamin D. NIH Office of Dietary Supplements. Retrieved March 17, 2023, from https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
4. Damas-Fuentes M, Boughanem H, Molina-Vega M, Tinahones FJ, Fernández-García JC, Macías-González M. 25-hydroxyvitamin D and testosterone levels association through body mass index: A cross-sectional study of young men with obesity. Front Endocrinol (Lausanne). 2022 Sep 2;13:960222. doi: 10.3389/fendo.2022.960222. PMID: 36120442; PMCID: PMC9478588.
5. Holt R, Juel Mortensen L, Harpelunde Poulsen K, Nielsen JE, Frederiksen H, Jørgensen N, Jørgensen A, Juul A, Blomberg Jensen M. Vitamin D and sex steroid production in men with normal or impaired Leydig cell function. J Steroid Biochem Mol Biol. 2020 May;199:105589. doi: 10.1016/j.jsbmb.2020.105589. Epub 2020 Jan 15. PMID: 31953167.
6. Pilz S, Frisch S, Koertke H, Kuhn J, Dreier J, Obermayer-Pietsch B, Wehr E, Zittermann A. Effect of vitamin D supplementation on testosterone levels in men. Horm Metab Res. 2011 Mar;43(3):223-5. doi: 10.1055/s-0030-1269854. Epub 2010 Dec 10. PMID: 21154195.
7. Huang Y, Jin H, Chen J, Jiang X, Li P, Ren Y, Liu W, Yao J, Folger JK, Smith GW, Lv L. Effect of Vitamin D on basal and Luteinizing Hormone (LH) induced testosterone production and mitochondrial dehydrogenase activity in cultured Leydig cells from immature and mature rams. Anim Reprod Sci. 2015 Jul;158:109-14. doi: 10.1016/j.anireprosci.2015.05.008. Epub 2015 May 18. PMID: 26024964.
8. Wang N, Zhai H, Zhu C, Li Q, Han B, Chen Y, Zhu C, Chen Y, Xia F, Lin D, Lu Y. Combined Association of Vitamin D and Sex Hormone Binding Globulin With Nonalcoholic Fatty Liver Disease in Men and Postmenopausal Women: A Cross-Sectional Study. Medicine (Baltimore). 2016 Jan;95(4):e2621. doi: 10.1097/MD.0000000000002621. PMID: 26825918; PMCID: PMC5291588.