Vitamin d and testosterone levels
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Vitamin D and Testosterone Levels: Overview of Associations
Research has explored the possible link between vitamin D status and testosterone levels in men, but findings are mixed and sometimes conflicting. Some studies suggest a positive association, while others find no significant relationship, especially in healthy populations 145678910.
Observational and Cross-Sectional Studies: Mixed Results
Several observational studies have found a slight but significant positive association between vitamin D levels and total testosterone, particularly in men with frailty or poor health status 16. However, in healthy young men and in large multi-ethnic cohorts, no significant association was found between vitamin D status and total testosterone levels 7810. Some studies did observe that lower vitamin D was linked to lower sex hormone-binding globulin (SHBG) and higher free testosterone, but not to total testosterone .
Vitamin D Supplementation: Effects on Testosterone
Randomized controlled trials (RCTs) have produced inconsistent results regarding the effect of vitamin D supplementation on testosterone levels. One RCT in overweight men with low vitamin D and low-normal testosterone found that vitamin D supplementation significantly increased total, bioactive, and free testosterone levels compared to placebo . However, other RCTs in healthy men with normal testosterone levels did not find any significant effect of vitamin D supplementation on total testosterone 59. Reviews of the literature also conclude that most RCTs fail to show a clear benefit of vitamin D supplementation for increasing testosterone 49.
Genetic and Mechanistic Evidence
A Mendelian randomization study provided evidence for a possible causal effect of higher vitamin D levels on higher total testosterone, suggesting a biological link . Mechanistically, vitamin D may play a role in testicular function and spermatogenesis, but clinical evidence for its impact on testosterone remains limited .
Population Differences and Confounding Factors
The association between vitamin D and testosterone may be more apparent in populations with poor health or frailty, and less so in healthy, young, or middle-aged men 17. Factors such as age, body mass index, comorbidities, and lifestyle can influence both vitamin D and testosterone levels, complicating the interpretation of results 14810.
Conclusion
Overall, while some evidence suggests a weak positive association between vitamin D and testosterone—especially in men with poor health—most studies in healthy men do not show a significant relationship. Vitamin D supplementation may increase testosterone in men with low baseline levels, but this effect is not consistently observed across all populations. More large, well-designed, long-term studies are needed to clarify the relationship and determine if vitamin D supplementation can reliably improve testosterone levels in men.
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