Can Vitamin D Restore Low Testosterone Levels?

Explore more about the intricate connection between Vitamin D and testosterone levels in women and men. Understand how optimizing these biomarkers influences overall health, immune function, and athletic performance.

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By Staff Writer
Lucia Gcingca
Edited by Lucia Gcingca

Published March 6, 2024.

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Testosterone has long been linked with notions of masculinity, while vitamin D has often been connected to robust bone health. However, recent research unveils a more intricate relationship between vitamin D and testosterone in women and men, indicating that these biomarkers play multifaceted roles in the body, with potential interconnections.

This article navigates beyond conventional wisdom, examining the interplay between vitamin D and testosterone. Explore the nuanced functions of these biomarkers, and discover why optimizing vitamin D and testosterone is beneficial to your overall well-being. Whether you're curious about testosterone in women, signs of low testosterone, or the impact of Vitamin D on testosterone levels, we've got you covered.

Some background on Vitamin D

The liver first converts vitamin D to 25-hydroxyvitamin D [25(OH)D], also known as calcidiol, before it is used in the body. Blood levels of this compound are the best indicator of one’s vitamin D status. [1] 

The kidneys then convert this substance to 1,25-dihydroxyVitamin D [1,25(OH)2D], also known as calcitriol, the active form of vitamin D. Calcitriol is the form of vitamin D that is considered to be a hormone. 

Vitamin D is an important fat-soluble nutrient naturally found in very few foods, such as mushrooms and fatty fish (i.e. sardines, salmon, mackerel). Other foods, such as milk, are fortified with vitamin D. The body does produce high amounts of vitamin D when skin is directly exposed to the sun (i.e. not through a window), so it’s sometimes referred to as the “sunshine vitamin.”

» Discover why blood testing is important for vitamin D

a bar chart with a pie chart on it

Did you know?

Excess sun exposure may elevate the risk of skin cancer. Due to the challenge of obtaining vitamin D from foods and the associated health risks of prolonged sun exposure, dietitians and doctors frequently recommend supplements in varying doses.

Vitamin D in the body

Vitamin D deficiency

Despite its ever-expanding catalog of beneficial physiological functions, vitamin D deficiency is still very prevalent. In 2011, it was estimated that 25% and 8% of Americans were at risk for vitamin D inadequacy and deficiency, respectively (serum 25(OH)D 30-49 and <30 nmol/L, respectively). [9]

Excess vitamin D

On the other side of the coin, excess vitamin D caused by sunlight exposure and high-dose vitamin D supplements can lead to kidney problems and nausea. [10

Some InsideTracker users, such as Laura Ingalls, experience joint pain as a result of excess vitamin D intake. Only about 14% of InsideTracker users have optimal levels of vitamin D, making it one of our least optimized biomarkers.

Vitamin D's versatility

Vitamin D is typically associated with maintaining bone health and helping the body absorb minerals such as calcium and magnesium. [2, 3] However, recent research has revealed that this biomarker also regulates cell growth and the immune system while maintaining neuromuscular and cardiovascular health. [4, 5, 6

Optimal levels of vitamin D are crucial for athletes, as vitamin D stimulates muscle growth, increases power, and cuts unnecessary body fat. [7, 8]

» Want to be a better athlete? Pay attention to vitamin D

Testosterone: Critical for performance and health

Testosterone is a crucial steroid hormone produced by both men and women. In men, testosterone levels elevate during puberty and stimulate the production of sperm and the formation of secondary sexual characteristics such as body hair and a deeper voice.

In both men and women, testosterone helps increase bone strength, stimulates the development of muscle mass and strength, and improves libido and mood. Testosterone is also crucial for athletes of both genders; it helps speed tissue recovery and stimulate red blood cell blood production.

Testosterone in the bloodstream

Testosterone is found in the bloodstream in one of two forms. It can be bound to the proteins albumin or sex hormone-binding globulin (SHBG), where it is known as “bound testosterone.” These proteins transport testosterone throughout the body.

However, it remains biologically inactive, meaning that it does not exert its typical effects upon body cells. About 97-98% of testosterone is bound to one of these proteins. [11]

Free and total testosterone

The other 2-3% circulates in the blood, where it can freely exert its biological effects. This portion is known as “free testosterone” (FT). While relatively small in proportion, FT is critical to maintaining optimal performance and health. The sum of bound and free testosterone is referred to as “total testosterone” (TT).

All four of these testosterone biomarkers—SHBG, free testosterone, albumin, and total testosterone—are crucial indicators of health and fitness and are measured in InsideTracker’s Ultimate Plan.

A poster with a man lifting a barbell - Testosterone Recovery Myth

Low testosterone in women and men

Knowing your testosterone levels is crucial for many reasons. Low testosterone in men is linked to infertility, irritability, and erectile dysfunction. In both men and women, low testosterone can lead to a variety of cardiovascular diseases and mental health concerns such as depression. [12, 13] 

Testosterone is critical for performance because it facilitates anabolic (recovery) processes, and low levels of free testosterone may lead to poor recovery, poorer fitness gains, and an increased chance of injury. [14] Elevated testosterone in women can also lead to sexual dysfunction.

» Check out science-backed ways to naturally increase testosterone

Pro tip: If your testosterone levels are too low, try to increase your recovery time if you’re overtraining, or lifting weights if you aren’t already exercising. Also, check for possible magnesium and zinc deficiencies and increase your intake of animal proteins.

Is there a relationship? Evidence of a possible connection

Results from a 2012 study showed a positive, independent association between concentrations of 25(OH)D and levels of TT and FT. [15] Most importantly, the researchers noted this association was linear at lower levels and plateaued at higher ones. [15] This suggests that the positive association between vitamin D and levels of free and total testosterone stops when vitamin D levels are optimal in the body.

a graph shows the number of hydrogens in a liquid - Vitamin D-1
Relationship between Total Testosterone and Concentration of Serum 25(OH)D Nimptsch, et al. Clinical Endocrinology, 2012

A reasonable amount of research suggests an association between adequate levels of vitamin D in the body, as measured by 25(OH)D, and TT.

Another study of middle-aged men displayed a positive correlation between TT, FT, and 25(OH)D. [16] It also found that subjects with optimized levels of testosterone (>26.51 ng/mL) had, on average, 15% more vitamin D than those with suboptimal levels of testosterone. [16]

Because vitamin D plays a key role in optimal athletic performance, scientists have also investigated the relationship between serum 25(OH)D levels and testosterone in young, active men. A 2015 study found serum vitamin D concentrations to be a significant, positive predictor of total testosterone. [17] This result suggests that highly active people—such as military personnel and athletes—may remedy low testosterone by optimizing their vitamin D levels.

a bar chart with a woman and a man standing next to each other
Vitamin D status and testosterone

Vitamin D and testosterone: Not just for men

Scientists have also observed a direct correlation between vitamin D and testosterone in women. In a recent cross-sectional study of women, researchers observed a positive, significant correlation between serum 25(OH)D concentrations and total testosterone levels. [18

This suggests that increasing levels of vitamin D may restore healthy levels of testosterone, though more research investigating the mechanism through which this happens needs to be done.

» Learn why women should care about testosterone

Does supplementation with vitamin D boost testosterone?

In a 2011 randomized controlled study, researchers found men who were given a daily high-dose vitamin D supplement significantly increased their total testosterone from 10.7 nmol/L to 13.4 nmol/L, whereas there were hardly any changes in testosterone concentrations in the group given a placebo. [19] 

These findings suggest that men deficient in vitamin D who take a proper vitamin D supplement may fix low levels of low testosterone.

A bar chart showing total testosterone levels before and after vitamin d supplementation.

Conflicting research on vitamin D supplementation

As expected, the concentrations of serum 25(OH)D increased substantially. However, there was no increase in mean testosterone concentrations at the end of any of the three studies. As a result, the researchers concluded that vitamin D supplementation was not associated with an increase in testosterone levels. [20] Thus, short-term, low-dose supplementation in vitamin D-deficient men may not increase testosterone in men with suboptimal levels.

Not all research indicates that vitamin D supplementation optimizes testosterone levels, though. In a 2015 study, Dutch researchers completed a meta-analysis of three intervention studies investigating the effects of vitamin D supplementation on serum testosterone concentrations in vitamin D-deficient subjects. 

A bar chart showing the percentage of test scores for testosterone in men before and after short term Vitamin D supplementation.

Analysis: Can vitamin D treat low testosterone?

  • A cross-sectional study observed a correlation between Vitamin D and testosterone in women.
  • One study shows an increase in levels of testosterone after providing high-dose, long-term vitamin D supplements to vitamin D-deficient men.
  • Another study observed no increase in testosterone after providing Vitamin D-deficient men with short-term Vitamin D supplementation.

Provided with this inconsistent evidence, what do we recommend? 

We encourage you to conduct your own experiment. 

First, use InsideTracker to monitor your Vitamin D and testosterone levels and use science-based recommendations to optimize them. If you are low in vitamin D and testosterone, see if regularly taking the proper vitamin D supplement increases your testosterone.

Remember the research: If you are already optimal in Vitamin D, supplementation is unlikely to affect your testosterone and may lead to too much Vitamin D in your body!

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Putting it into perspective

Because vitamin D and testosterone influence the body’s health and performance, it is crucial that you consistently monitor the levels of these biomarkers to make sure that they are optimized.

Research suggests that there is a correlation between adequate levels of vitamin D and adequate levels of testosterone. However, supplementation may only help you boost testosterone if you are already proven to be deficient in both testosterone and vitamin D.

a green and white sign that says vitamin d


[1] Ross, A. Catherine, et. al. (editors) Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: National Academies Press, 2011.

[2] Horsley, Tanya, et al. Effectiveness and safety of Vitamin D in relation to bone health. US Department of Health and Human Services, Public Health Service, Agency for Healthcare Research and Quality, 2007.

[3] Ross, A. Catharine, et al. The 2011 report on dietary reference intakes for calcium and Vitamin D from the Institute of Medicine: What clinicians need to knowThe Journal of Clinical Endocrinology & Metabolism 96.1 (2011): 53-58.

[4] Shils, Maurice Edward, and Moshe Shike, eds. Modern Nutrition in Health and Disease. Philadelphia: Lippincott Williams & Wilkins, 2006.

[5] Wang, Lu, et al. Systematic review: Vitamin D and calcium supplementation in prevention of cardiovascular eventsAnnals of Internal Medicine 152.5 (2010): 315-323.

[6] Hossein-Nezhad, Arash, Avrum Spira, and Michael F. Holick. Influence of Vitamin D status and Vitamin D3 supplementation on genome wide expression of white blood cells: A randomized double-blind clinical trialPLoS One 8.3 (2013): e58725.

[7] Wyon, Matthew A., et al. The influence of winter Vitamin D supplementation on muscle function and injury occurrence in elite ballet dancers: A controlled studyJournal of Science and Medicine in Sport 17.1 (2014): 8-12.

[8] Forney, Laura A., et al. Vitamin D Status, Body Composition, and Fitness Measures in College-Aged StudentsThe Journal of Strength & Conditioning Research 28.3 (2014): 814-824.

[9] Looker A.C., C.L. Johnson, D.A. Lacher, et al. Vitamin D status: United States 2001–2006. NCHS data brief, no 59. Hyattsville, MD: National Center for Health Statistics, 2011.

[10] Jones, Glenville. Pharmacokinetics of Vitamin D toxicityThe American Journal of Clinical Nutrition 88.2 (2008): 582S-586S.

[11] Emadi-Konjin, Pasha, Jerald Bain, and Irvin L. Bromberg. Evaluation of an algorithm for calculation of serum 'bioavailable' testosterone (BAT)Clinical Biochemistry 36.8 (2003): 591-596.

[12] Westley, Christopher J., Richard L. Amdur, and Michael S. Irwig. High Rates of Depression and Depressive Symptoms among Men Referred for Borderline Testosterone LevelsThe Journal of Sexual Medicine (2015).

[13] Wickramatilake, Chandima Madhu, Mohamed R. Mohideen, and Chitra Pathirana. Association of metabolic syndrome with testosterone and inflammation in menAnnales d'Endocrinologie. Elsevier Masson, 2015.

[14] Chung, Kyung-Jin and Khae-Hawn Kim. Forbidden fruit for athletes, but possible divine blessing for rehabilitation: testosteroneJournal of Exercise Rehabilitation 11.1 (2015): 2.

[15] Nimptsch, Katharina, et al. Association between plasma 25‐OH Vitamin D and testosterone levels in menClinical Endocrinology 77.1 (2012): 106-112.

[16] Tak, Young Jin, et al. Serum 25-hydroxyVitamin D levels and testosterone deficiency in middle-aged Korean men: a cross-sectional studyAsian Journal of Andrology 17.2 (2015): 324.

[17] Wentz, Laurel, et al. Vitamin D Correlation with Testosterone Concentration in US Army Special Operations PersonnelThe FASEB Journal 29.1 Supplement (2015): 733-5.

[18] Chang, Eun Mi, et al. Association between sex steroids, ovarian reserve, and Vitamin D levels in healthy non-obese womenThe Journal of Clinical Endocrinology & Metabolism 99.7 (2014): 2526-2532.

[19] Pilz, S., et al. Effect of Vitamin D supplementation on testosterone levels in menHormone and Metabolic Research 43.3 (2011): 223.

[20] Heijboer, Annemieke C., et al. Vitamin D supplementation and testosterone concentrations in male human subjectsClinical endocrinology (2015).