The health problems of getting excessive vitamin D from the sun/UVB are well known

1. Increased skin cancer
2. Excess calcium Death by Calcium, book by Thomas Levy – Dec 2013
3. Wrinkles and UVB and Overview UV and vitamin D

The benefits of getting more vitamin D are also well known Proof that Vitamin D Works

Evolution found a balance between the benefits and risks in a very sunny climate: 50 ng

Is 50 ng of vitamin D too high, just right, or not enough
Chart of Vitamin D levels vs race - April 2013 has the following

With supplementation we have an opportunity to increase vitamin D levels beyond evolutionary limits
   – provided we balance the cofactors and avoid excess sun/UVB

Low cost cofactors for vitamin D
Increased Vitamin K2 reduces the problems of excess Calcium – Nov 2013
Decrease Calcium and Increase Magnesium when increasing vitamin D has the a notional chart

How much is "optimal"? We do not know, but there are some interesting clues

• 80 ng achieved by 2,000 patients of one doctor. Their visits by patients dropped 4X: from 4/year to 1/ year
• 105 ng – Resulted in huge decrease in Psorasis
• 150 ng – resulted in CURING Multiple Sclerosis
• Items in category Optimum Vitamin D 74 items

GrassRootsHealth chart shows that a wide variety of health problems decrease with increasing Vitami D levels

Increasing number of PubMed articles about "Optimum Vitamin D"

Personal note: My vitamin D level is typically above 100 ng