Vitamin — Endocrine
Vitamin D (25-OH)
25-hydroxyvitamin D is the storage form of vitamin D and the standard status marker.
Reference range
Optimization target: 40–60 ng/mL. Functional optimization context only — not a diagnostic assertion. Range varies by lab, age, and sex.
Why it matters
Vitamin D status influences immune function, bone health, mood, and a long list of downstream signaling pathways. Insufficiency is common, easy to test, and inexpensive to correct. Most REVRCEL members benefit from periodic measurement and modest supplementation toward the optimization range.
How REVRCEL clinicians read it
Sun exposure, latitude, body composition, and supplementation all affect serum 25-OH D. Re-test after 8–12 weeks of changes.
Included in
- Core Bloodwork
Common questions
Should I supplement vitamin D?
Many adults benefit from supplementation toward the optimization range. Test before and after to titrate.
Related biomarkers
Statements have not been evaluated by the FDA. This page is educational and is not medical advice.