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Vitamin D Dosing Calculator

"GrassrootsHealth has made it easier for individuals to determine how much vitamin D to take to reach their desired serum level goal with the creation of the D*calculator. It is a simple, straight-forward way to answer the frequently asked question "How much vitamin D should I take?".

"The D*calculator was created using data from our D*action project. An individual can enter their current vitamin D serum level, desired vitamin D serum level, and weight. The calculator will determine how much additional daily vitamin D is needed to move from the current serum level to the desired serum level with both a 50% probability and a 90% probability."


"An "erythema dose" is used by doctors to define the amount of ultraviolet radiation, from the sun or ultraviolet lamp, which results in a reddening of the skin. A minimal erythema dose is defined by a pinkness of the skin about 1-6 hours after sun exposure, going away within 24 hours. Sunny Hippocrates, our cartoon mascot this month, has been telling you to get a *smidge* pink. There is no single number, due in part to differences in skin type and other individual differences in vitamin D production, but one minimal erythema dose is equivalent to roughly 10,000 - 25,000 IU of supplemental vitamin D."

"How long does that take?

The time to reach a minimal erythema dose depends on

1) Skin type

2) UV strength

It could be as short as 5 minutes (very fair skin with high UV strength) and as long as hours/never (very dark skin with very low UV strength)."

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