vitamin
Vitamin D3
Supports bone health, immune signaling, and muscle function.
What It Does
Vitamin D regulates calcium and phosphate balance, supporting bone mineralization.
It also influences immune and muscle function, especially when deficiency is present.
Low sunlight exposure, darker skin, and higher latitudes increase deficiency risk.
Who Needs It Most
| Demographic | Target Intake | Upper Limit |
|---|---|---|
| all, age:0-1 | 400 IU (10 mcg) | 1000 IU |
| all, age:1-8 | 600 IU (15 mcg) | 2500 IU |
| all, age:9-18 | 600 IU (15 mcg) | 4000 IU |
| all, age:19-50 | 600-1000 IU (15-25 mcg) | 4000 IU |
| all, age:51-120 | 800-2000 IU (20-50 mcg) | 4000 IU |
| all, low_sun_dark_skin, northern_climate | 2000-4000 IU (50-100 mcg) | 4000 IU |
| female, pregnant | 600-1000 IU (15-25 mcg) | 4000 IU |
| all, vegan | 1000-2000 IU (25-50 mcg) | 4000 IU |
| female, pcos | 1000-2000 IU | 4000 IU |
| all, osteoporosis | 1000-2000 IU | 4000 IU |
| all, diabetes | 1000-2000 IU | 4000 IU |
| all, mental_health | 1000-2000 IU | 4000 IU |
Signs of Deficiency
- Low mood
- Frequent illness
- Muscle weakness
Best Food Sources
Fatty fish
Moderate
Fortified milk
Low to moderate
Sun exposure
Variable
Supplement Guide
Best forms: Cholecalciferol (D3)
What to look for: Dose matched to blood level and season, Pair with magnesium and K2 when appropriate
What to avoid: Chronic high dosing without monitoring
Timing: Morning or midday with fat-containing meal.
Who Should Avoid It
No major common contraindications in our database for this nutrient. Always check medication interactions.
The Research
PubMed citations are temporarily unavailable.
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