Is a blood level of 80 ng/ml of vitamin d too high?

Vitamin D toxicity: No. Vitamin d has no known adverse effects up to levels of 100 ng/ml. Obvious signs of toxicity emerge at levels above 150 ng/ml. Signs of toxicity include: constipation; decreased appetite (anorexia); dehydration; fatigue; irritability; muscle weakness; vomiting; heart rhythm abnormalities; kidney stones; and polyuria (frequent urination).

Levels: The literature is variable about vitamin D levels. However, many sources would advocate 80 ng/ml as an optimal level.