Site Map
Interactive tools
- Sunlight Calculator
Estimate how much vitamin D your body makes from sun exposure.
- Latent Vitamin D Reserves Calculator
Model your stored cholecalciferol through winter.
- Blood Test Interpreter
Understand your serum 25(OH)D result.
Guides & deep dives
- Complete Vitamin D Guide
Everything you need to know in one place.
- How the Calculator Works
The physics and physiology behind the math.
- Vitamin D Winter
Latitude, UVB, and seasonal deficiency.
Reference articles
- Benefits (evidence-ranked)
What the clinical trials really show.
- Deficiency Symptoms
Nine signs your 25(OH)D may be low.
- Dosage Guide
RDA, UL, and repletion protocols.
- Toxicity & Safe Upper Limits
Can you take too much?
- Vitamin D and Immunity
Cathelicidin, T-cell modulation, RCT evidence.
- Vitamin D in Pregnancy
Requirements and risks for expectant mothers.
- Vitamin D for Kids
Infants, children, and adolescents.
- Foods High in Vitamin D
Searchable table with IU per serving.
Reference
- Frequently Asked Questions
18 answered questions.
- Glossary
Terminology and abbreviations.
- About
Methodology and site background.
- Contact
Feedback and inquiries.