Can your genes affect your vitamin D level?
Explore the genetic variants associated with blood vitamin D levels.
Vitamin D is measured in blood as 25-hydroxyvitamin D. The level depends mostly on sunlight and diet — but large studies show that a smaller share of the variation between people is linked to genetic variants in the vitamin's transport and metabolism pathways.
What the analysis shows
DNAHelper shows which vitamin D-associated variants your raw file contains. The result is a genetic association, not a lab result — an actual level requires a blood test. The analysis is based on the traits 25-hydroxyvitamin D3 measurement, vitamin D deficiency (397 associated variants, strong evidence strength).
Which variants matter
GC encodes the protein that binds and transports vitamin D in the blood — variants here are the most consistently linked to measured levels. CYP2R1 converts vitamin D to its active form.
The DHCR7/NADSYN1 region affects how much of the provitamin is converted in the skin, and CYP24A1 controls breakdown of the active form.
What research has actually found
GWAS with hundreds of thousands of participants have replicated the links to GC, CYP2R1, DHCR7 and CYP24A1. Together, the known variants explain a few percent of the level differences between people.
The links are statistical: a genetic profile leaning toward lower levels says nothing about where your level sits without a measurement.
What matters more than genes
Season and latitude dominate — at northern latitudes vitamin D levels drop markedly during the winter half of the year regardless of genetics. Fatty fish, fortified foods and supplements have a direct effect.
Skin pigmentation, age, body weight and time in the sun all outweigh the individual genetic variants.
What the result means — and does not mean
The analysis is based on the traits 25-hydroxyvitamin D3 measurement, vitamin D deficiency (strong evidence strength). Associations are statistical — they describe populations, not destinies. Read how we grade evidence in our methodology.
Privacy: your file never leaves the browser
You pick your raw file locally — it is parsed and analysed entirely in your browser and is not uploaded for the standard analysis. The only exception is the optional DNA Chat feature where you, after explicit consent, can share selected variants. Read the privacy policy · What happens to your DNA file?
Compatible raw files
Works with raw data exports from MyHeritage, 23andMe, AncestryDNA and FamilyTreeDNA (.txt, .csv, .zip). The download guides show exactly where to find the file at your provider — and the file formats are explained here.
Also read: Method & science · All analyses · All traits · Skin pigmentation and genes