Vitamin D: It's Not a Vitamin, It's an Essential Pro-Hormone
Why almost everyone is deficient, why the sun isn't enough, and how to supplement safely for immunity and bones.
Aevos Health Research
Research & Analysis
We call it Vitamin D by historical mistake. In reality, it's a steroid hormone that controls the expression of over 1,000 genes (about 5% of the human genome).
Vitamin D receptors are found in almost every cell in the body, from the brain to the immune system.
Why Are We All Deficient?
We are "indoor animals." We work in offices, commute by car, live indoors. When we go out, we cover up or use sunscreen (rightly so for the skin, but this blocks Vit D production).
Furthermore, with age, the skin becomes less efficient at synthesizing it from the sun.
The Benefits - Beyond Bones
Everyone knows it's needed for bones (osteoporosis prevention). But optimal levels are associated with:
- Enhanced Immunity: Modulates the immune response, reducing the risk of respiratory infections and autoimmune diseases.
- Mood: Low levels are correlated with depression and seasonal affective disorder (SAD).
- Metabolic Health: Deficiency is associated with a higher risk of insulin resistance.
How to Supplement - Safe Protocol
See our general supplement guide for context.
- Test: Don't guess. Get a blood test (25-OH Vitamin D).
- Form: Choose Vitamin D3 (Cholecalciferol), the active form, not D2.
- Co-factors: Always take it with a fatty meal (it's fat-soluble) and pair it with Vitamin K2 (MK-7) and Magnesium (necessary to activate it).
- Dosage: Varies enormously. For maintenance, 2,000-4,000 IU per day is common, but correcting a deficiency requires higher doses under medical supervision.
Don't wait until you break a bone to worry about Vitamin D. It's the cheapest life insurance that exists.
Does your lifestyle put you at risk of deficiency?
Check your habitsFrequently Asked Questions
Related Articles
Supplement Guide: What Works, What's Hype, and What to Avoid
A rational approach to supplementation. Don't waste money on magic pills; invest in molecules supported by clinical trials.
Magnesium: The Relaxation Mineral Everyone Is Missing
Stress, poor sleep, and cramps? It could be magnesium deficiency. Guide to the best forms (bisglycinate, citrate, threonate).
Protein Powders: A Real Cost-Benefit Guide
Whey, casein, plant-based, collagen: what's actually worth your money? A brutally honest analysis of quality, absorption, and price per gram.