Vitamin D3
5000 IU · Daily
Evidence
- Human Studies
- 200
- Animal Studies
- 80
- Clinical Status
- Dietary Supplement
- Confidence
- High
- Long-Term Safety
- Well-established at standard doses; toxicity is rare but possible with chronic high-dose use without monitoring
What this score is: a measure of how much research exists and how far along it is (animal-only vs. human trials, research-stage vs. FDA approved) — not how safe, effective, or worth trying a compound is. A low score usually means “early stage” or “understudied,” not “bad.” A high score doesn’t mean “better” for your goals than a lower-scored one.
This is not my personal rating of the compound, not a recommendation, and not medical advice. It’s a general research synthesis for informational purposes only, not a live literature count. See the linked research and talk to a licensed clinician before making decisions based on it.
Mechanism
A fat-soluble vitamin/prohormone essential for calcium absorption and bone mineralization, with receptors throughout the body implicated in immune and muscle function. Evidence is strongest for correcting deficiency and bone health; large trials (e.g. VITAL) found more modest or null effects on other outcomes in people who weren’t deficient to begin with.
Common Protocols
- 1000–5000 IU daily depending on baseline levels — testing blood 25-OH-D levels before/during supplementation is the most reliable way to dose
- Take with a fat-containing meal for better absorption
Side Effects
- Rare at standard doses
Interactions
- Increases calcium absorption — caution combining with calcium supplements if you have a history of kidney stones
Practical Details
- Cost
- $
- Typical Dose
- 5000 IU
- Storage
- Store in a cool, dry place, away from light
Research Links
Bone and immune support; take with a fat-containing meal