Nutrition & Diet

Vitamin D and Testosterone: The Most Underrated Link

Vitamin D is a steroid hormone. Here's how it influences testosterone and the dose that actually corrects deficiency.

7 min read · XT Editorial Team · Reviewed & updated

Vitamin D is a hormone

Despite the name, vitamin D functions as a steroid hormone. Most men in northern latitudes are deficient, and deficiency correlates strongly with sub-optimal testosterone.

Testing and dosing

Test 25-hydroxy D. Target 40–60 ng/mL. Most men need 2,000–5,000 IU daily to reach that range, taken with a fat-containing meal.

Frequently asked questions

Can sunlight replace supplements?
Sometimes, depending on latitude, season, and skin tone. Testing is the only way to know.
Do I need K2 with D3?
Some evidence supports co-supplementation for calcium handling, especially at higher D doses.
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