Overview
What is vitamin D?
What are vitamin D’s main benefits?
What are vitamin D’s main drawbacks?
How does vitamin D work?
Dosage information
Formulation
Vitamin D supplements are available in two main forms: vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol). Vitamin D3 supplementation (cholecalciferol) is generally recommended over D2 supplementation (ergocalciferol), because D3 tends to raise blood levels more effectively.[1][2]
Vitamin D comes in a wide range of formulations, including tablets, capsules, soft gels, drops, and powder.
Range of dosages studied
Studies have varied greatly in the dosages of vitamin D used, ranging anywhere from 400 IU (10 μg) daily to 300,000 IU (7,500 μg) daily — far beyond what is recommended! Sometimes vitamin D has been given at longer intervals, such as weekly, monthly, or even yearly.[4]
Most people should consume at least the recommended dietary allowance (RDA) of vitamin D, which includes vitamin D from all sources (i.e., food, drinks, supplements, and medications) combined. It is common for supplemental doses of vitamin D to exceed the RDA; however, it’s important not to exceed the tolerable upper intake level (UL) unless advised and monitored by a healthcare professional.
Recommended Dietary Allowance
| AGE | MALE | FEMALE | PREGNANT | LACTATING |
|---|---|---|---|---|
| 0–12 months | 10 μg (400 IU)* | 10 μg (400 IU)* | — | — |
| 1–13 years | 15 μg (600 IU) | 15 μg (600 IU) | — | — |
| 14–18 years | 15 μg (600 IU) | 15 μg (600 IU) | 15 μg (600 IU) | 15 μg (600 IU) |
| 19–50 years | 15 μg (600 IU) | 15 μg (600 IU) | 15 μg (600 IU) | 15 μg (600 IU) |
| 51–70 years | 15 μg (600 IU) | 15 μg (600 IU) | — | — |
| >70 years | 20 μg (800 IU) | 20 μg (800 IU) | — | — |
* Adequate Intake (AI))
Reference: Institute of Medicine. Dietary Reference Intakes for Adequacy: Calcium and Vitamin D (chapter 5 in Dietary Reference Intakes for Calcium and Vitamin D. The National Academies Press. 2011. DOI: 10.17226/13050)
Tolerable Upper Intake Level
| AGE / SITUATION | DOSE |
|---|---|
| 0–6 months | 25 μg (1,000 IU) |
| 7–12 months | 38 μg (1,500 IU) |
| 1–3 years | 63 μg (2,500 IU) |
| 4–8 years | 75 μg (3,000 IU) |
| 9–13 years | 100 μg (4,000 IU) |
| 14–18 years | 100 μg (4,000 IU) |
| >18 years | 100 μg (4,000 IU) |
| Pregnant or breastfeeding | 100 μg (4,000 IU) |
Reference: [5]
Other considerations
Vitamin D is absorbed better when taken with food or a source of fat.[6] However, taking it with or without food is unlikely to have a large effect on its ability to increase vitamin D levels in the long run.[7][8][6]
Frequently asked questions
Is there a difference between Vitamin D2 and Vitamin D3?
What are some dietary sources of vitamin D3?
Should vitamin K be supplemented alongside vitamin D?
Can vitamin D status affect testosterone levels?
Is there a link between vitamin D levels and all-cause mortality?
Update History
Safety Information added
Page-wide language tweaks
Dosage info and a FAQ updated
