Table 1. Initial treatment of vitamin D deficiency.

Vitamin D status	25-hydroxyvitamin D concentration (at the end of winter)	Recommended vitamin D supplementation*	Follow-up
Mild deficiency	30–49 nanomol/L	1000–2000 IU per day	3–5 months after starting supplementation; annually recommended if receiving treatment for osteoporosis
Moderate deficiency	12.5–29 nanomol/L	3000–5000 IU per day (for 6–12 weeks) followed by a maintenance dose of 1000–2000 IU per day
Severe deficiency	<12.5 nanomol/L

* Alternatively, higher doses may be given less frequently when needed.