Vitamin D is a fat-soluble prohormone that primarily regulates calcium and phosphorus metabolism, which is critical for bone health. Its receptor (VDR) is present in nearly every cell type, allowing it to modulate the expression of hundreds of genes involved in immune function, inflammation, and cell growth. Correcting widespread deficiency is a key healthspan strategy to support skeletal integrity and immune competence, potentially reducing the risk of various age-related conditions.
Verdict
Essential for correcting deficiency; a foundational supplement for most individuals.
HEALTHSPAN IMPACT
High Value
RISK LEVEL
Low
EVIDENCE GRADE
A
MONTHLY COST
$5 - $15
Protocol
- Daily supplementation of 1,000-4,000 IU of Vitamin D3 is common to maintain optimal levels.
- Blood levels (25-hydroxyvitamin D) are often targeted to be between 30-60 ng/mL.
- Higher loading doses may be used initially to correct a severe deficiency under medical supervision.
Flags
- Toxicity (hypercalcemia) can occur with prolonged, very high doses (>10,000 IU/day).
- As a fat-soluble vitamin, it should be taken with a source of fat for optimal absorption.
- May interact with certain medications, including steroids, statins, and thiazide diuretics.
- Optimal levels should be confirmed with a blood test (25-hydroxyvitamin D).