25-Hydroxyvitamin D
25-hydroxyvitamin D is the major circulating form of vitamin D and the standard population status marker. Across US males aged 30 to 39, the median 25-hydroxyvitamin D in NHANES 2017-2018 is 23.3 ng/mL.
Unit: ng/mL · 12 slices · age and sex · 1 source
Filed under panels: Vitamins · topics: Nutrition
25-Hydroxyvitamin D (25(OH)D) is the major circulating form of vitamin D and is used to describe vitamin D status in the body. It reflects both dietary intake and skin synthesis from sunlight. The values shown here are total 25(OH)D measured by liquid chromatography mass spectrometry, summing the D2 and D3 forms and excluding the C3-epi-25(OH)D3 isomer. NHANES publishes the value in nmol/L; LabNorms displays it in ng/mL using the standard conversion (divide by 2.496).
Population Distribution
Browse by Demographic
| Age (years) | male (ng/mL) | female (ng/mL) |
|---|---|---|
| 20-29 | 11.1–37.9 (23.4) | 9.8–42.9 (24.0) |
| 30-39 | 10.3–38.9 (23.3) | 11.6–40.9 (25.2) |
| 40-49 | 11.0–39.9 (26.7) | 10.1–48.0 (27.8) |
| 50-59 | 13.4–48.1 (29.8) | 12.4–55.3 (29.7) |
| 60-69 | 14.5–52.7 (29.5) | 13.1–62.5 (36.1) |
| 70+ | 16.3–57.9 (34.7) | 18.2–61.7 (37.5) |
Frequently Asked Questions
Why does the population distribution of vitamin D vary so much?
25(OH)D is shaped by sun exposure, latitude, season, skin pigmentation, body composition, dietary intake, and supplement use. The population distribution therefore has a wide spread compared with most other vitamins.
Is this the active form of vitamin D?
No. 25-Hydroxyvitamin D is the storage form. The biologically active hormone is 1,25-dihydroxyvitamin D, which is regulated by parathyroid hormone and not directly proportional to 25(OH)D in most circumstances. 25(OH)D is the standard status marker because it is more stable and more abundant.
Why does NHANES publish in nmol/L when US laboratories use ng/mL?
NHANES uses SI units in published variables. US clinical laboratories typically report 25(OH)D in ng/mL. The conversion is exact: ng/mL = nmol/L / 2.496. LabNorms stores values in ng/mL to match US-clinical convention and exposes nmol/L via the unit toggle.