What I do is test my D3 levels in order to keep them between 60 to 70ng/ml. From what I've read, everyone is different in their D3 needs.
The folly of an RDA for vitamin D
http://www.heartscanblog.org/2011/01/fo ... min-d.html
From the article:
Quote:
Tom is a 50-year old, 198-lb white male. At the start, his 25-hydroxy vitamin D level was 28.8 ng/ml in July. Tom supplements vitamin D, 2000 units per day, in gelcap form. Six months later in January (winter), Tom's 25-hydroxy vitamin D level: 67.4 ng/ml.
Jerry is another 50-year old white male with similar build and weight. Jerry's starting summer 25-hydroxy vitamin D level: 26.4 ng/ml. Jerry takes 12,000 units vitamin D per day, also in gelcap form. In winter, six months later, Jerry's 25-hydroxy vitamin D level: 63.2 ng/ml.
Two men, similar builds, similar body weight, both Caucasian, similar starting levels of 25-hydroxy vitamin D. Yet they have markedly different needs for vitamin D dose to achieve a similar level of 25-hydroxy vitamin D. Why?