Vitamin D3

Where to get tested

• Personalabs | Vitamin D Test Description
• Home Test Kits
• D*action Study

How much to take

Rule of thumb: 1000 units/day of D3 raises blood level by 10,000 ng/ml. Most adults need to take at least about 8000 units of D3 per day during the less sunny time of the year. There is no known toxicity from taking up to 10000 units per day.

Links

• How Much Vitamin D Do You Really Need to Take? (Dr Mercola)
• Vitamin D Prevents Cancer: Is It True? video
• Grassroots Health
  • Documents (PDFs) - How it Works | Vitamin D Prevents - Is It True?
    
• Dietary Supplement Fact Sheet: Vitamin D
  
• Linus Pauling Institute, Micronutrient Information Center: Vitamin D
  
• Vitamin D Council | Toxicity | Home Test Kits
• The Vitamin D and Omega-3 Trial (VITAL)
• John Cannell, MD Article - Vitamin A, even in relatively low amounts, appears to thwart vitamin D's association with reduced rates of colon cancer. The benefits of vitamin D are almost entirely negated by about 3,000 IU/day of vitamin A (retinol) intake.
• The Truth About Vitamin D Toxicity - There is no known toxicity from taking up to 10000 units per day. Humans make at least 10,000 units of vitamin D within 30 minutes of full body exposure to the sun.
• Vitamin D and Colon Cancer
• Mercola: Vitamin A Impairs Vitamin D Benefits
• Mercola: Vitamin D Resource Page