LONGEVITY
Vitamin D, 25-Hydroxy
Also known as 25-OH Vit D
What it is
Vitamin D 25-hydroxy is the stored form of vitamin D and the best single measure of vitamin D status.
Why it matters
Vitamin D affects bone health, immunity, mood, and hormone signaling. Insufficiency is common and easily corrected.
Range GPLX watches for
GPLX generally targets 25-OH vitamin D of 40–60 ng/mL in symptomatic patients. The lab reference lower limit is often set at 30 ng/mL.
This educational range is not a personal diagnostic threshold. Your physician interprets your result in context of your full biomarker panel, medications, symptoms, and history.
What abnormal values can suggest
If low
A low vitamin D value can suggest low sun exposure, low dietary intake, malabsorption, or chronic disease.
If high
A high vitamin D value usually reflects over-supplementation and should prompt dose reduction.
This marker is reviewed when clinically appropriate as part of physician-directed labs. Membership is $39.99/month; consultation is $30.
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