VITAMIN D
INTERPRETER
Vitamin D is crucial for bone health, immune function, and much more. Enter your 25-OH vitamin D level to understand what it means and whether you're in the optimal range.
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Also called 25-hydroxyvitamin D or calcidiol
UNIT CONVERSION
ng/mL x 2.5 = nmol/L
nmol/L x 0.4 = ng/mL
Levels naturally vary by season
// INTERPRETATION
YOUR VITAMIN D
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ng/mL
Enter your vitamin D value to see interpretation.
INSTITUTE OF MEDICINE
20-50 ng/mL
"Sufficient"
ENDOCRINE SOCIETY
40-60 ng/mL
"Optimal"
Guidance: Enter your value for supplementation guidance.
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CLASSIFICATION RANGES
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UNDERSTANDING VITAMIN D
WHY VITAMIN D MATTERS
Vitamin D is actually a hormone that affects nearly every cell in your body. Beyond its well-known role in calcium absorption and bone health, it influences immune function, mood, muscle strength, and more.
FUNCTIONS OF VITAMIN D
- Bone health: Essential for calcium absorption and bone mineralization
- Immune function: Modulates both innate and adaptive immunity
- Muscle function: Affects muscle strength and reduces fall risk
- Mood: Low levels associated with depression
- Cardiovascular: May influence heart and blood vessel function
SOURCES OF VITAMIN D
- Sun exposure: UVB rays trigger vitamin D synthesis in skin
- Fatty fish: Salmon, mackerel, sardines
- Fortified foods: Milk, cereals, orange juice
- Egg yolks: Moderate amounts
- Supplements: D3 (cholecalciferol) preferred over D2
SUPPLEMENTATION GUIDELINES
| CURRENT LEVEL | TYPICAL DOSE | RETEST |
|---|---|---|
| <20 ng/mL | 4,000-5,000 IU/day | 8-12 weeks |
| 20-30 ng/mL | 2,000-4,000 IU/day | 3 months |
| 30-40 ng/mL | 1,000-2,000 IU/day | 6 months |
| >40 ng/mL | 1,000 IU/day (maintenance) | Annually |
These are general guidelines. Individual needs vary based on body weight, absorption, sun exposure, and health conditions. Always consult your healthcare provider.
IMPORTANT CONSIDERATIONS
- Take with fat: Vitamin D is fat-soluble; absorption improves with fatty meals
- Check magnesium: Needed for vitamin D metabolism
- K2 synergy: Vitamin K2 helps direct calcium to bones, not arteries
- Don't megadose: Toxicity is possible with very high doses over time
TRACK YOUR PROGRESS WITH BODYOS
Take your health optimization to the next level. The BodyOS app lets you track all your metrics in one place, get personalized insights, and see your progress over time.
Important: This tool is for educational purposes only. Vitamin D supplementation should be guided by your healthcare provider, especially if you have kidney disease, sarcoidosis, or other conditions affecting calcium metabolism. Do not exceed recommended doses without medical supervision.