Vitamin D Status (25-OH-D)
Blood 25-hydroxyvitamin D, the storage form, in ng/mL. Optimal range: 40-60 ng/mL.
What it measures
Blood 25-hydroxyvitamin D, the storage form, in ng/mL. The standard marker of vitamin D status from sun, food, and supplements.
Why it matters
Vitamin D governs calcium absorption, bone health, and immune function. Deficiency is widespread, especially in northern latitudes and winter months.
Optimal ranges
Sourced targets, not just lab reference ranges. Lab ranges describe the population; these describe where the evidence says you want to be.
Sourcing note
This target rests on credible but thin sourcing, such as expert-opinion statements or a single review. Stronger than a heuristic, weaker than a guideline. We upgrade it as better sources land.
| Range | Context |
|---|---|
| 40-60 ng/mL | Endocrine Society 2011 clinical practice guideline (Holick, JCEM): minimum 30 ng/mL, recommended 40-60 ng/mL to guarantee sufficiency. Note: the 2024 Endocrine Society guideline no longer endorses a specific target, so this is contested. |
How to improve it
- 1
Sensible sun exposure (skin type and latitude dependent)
- 2
Vitamin D3 supplementation, typically 1,000-2,000 IU daily
- 3
Take with a fat-containing meal for absorption
- 4
Retest after 3 months of a new dose
Connected to
Goals
Ingredients
Longevity Lab Report
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Educational information, not medical advice. Talk to your doctor before acting on any biomarker result.