Use the correct life-stage reference
NIH ODS lists an Adequate Intake of 10 mcg, or 400 IU, daily for infants through twelve months and an RDA of 15 mcg, or 600 IU, at ages 1–18. These refer to total intake for generally healthy children under the reference assumptions. Clinician-directed treatment of a deficiency or absorption disorder can use another regimen and should not be inferred from a routine intake table. [1]
An amount in IU is not a volume
Liquid preparations can differ in concentration. Read whether the declared amount is per drop, per mL or another measured serving before following an instruction. A dropper from a different product is not a reliable conversion device. Include fortified foods and other supplements when reviewing the child’s total exposure; excessive vitamin D can raise blood calcium. [1]
A hypothetical concentration comparison
A hypothetical liquid containing 400 IU per mL requires a different volume to deliver a specified amount than one containing 400 IU per drop. This example illustrates why the units must be checked, not how to choose a child’s dose. Ask the pharmacist or pediatric clinician to confirm the exact product and measurement if the instructions are unclear. [1]
| Hypothetical label | What the denominator means |
|---|---|
| 400 IU per mL | Amount in one measured milliliter |
| 400 IU per drop | Amount in one specified drop |
Sources for this article
- Vitamin D - Health Professional Fact Sheet
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product.