About Vitamin D3

Causes & Dosage

Understand Vitamin D3, the common causes of deficiency, and important information about supplementation and dosage.

Understanding Vitamin D3

What is Vitamin D3?

Cholecalciferol is the scientific name for Vitamin D3.
Vitamin D3 can be taken to support overall health and can also be used when Vitamin D3 levels are low.
Vitamin D3 supports the kidneys in maintaining phosphate levels in the blood and plays an important role in mineral balance.
It can also be used in people with underactive parathyroid glands under medical supervision.

Vitamin D Deficiency

01
Vitamin D plays an important role in supporting normal immune system function.
02
Vitamin D3 deficiency can affect bone health. In children it may be associated with bow-shaped legs, while adults may develop softer bones, known as osteomalacia.
03
Low Vitamin D3 levels can also occur alongside certain digestive problems.
04
Sunlight is a natural source of Vitamin D3. People who spend very little time outdoors may therefore be more likely to have low levels.
05
People with darker skin may require greater sunlight exposure because melanin can reduce Vitamin D production in the skin.
06
Sun protection practices can also reduce the amount of Vitamin D produced through sunlight.

Supplementation

Vitamin D3 is available in tablet formulations with different strengths, including 400 IU and 1000 IU tablets.
Vitamin D3 may also be available in combination with calcium in a single tablet.
The original guidance states that adults should not consume more than 4,000 IU of Vitamin D3 per day unless it has been prescribed by a doctor.
Vitamin D is generally best taken with a meal, although instructions may differ for prescribed forms.
For people over 50 with osteoporosis, the page references 800–1000 IU (20–25 mcg) of Vitamin D daily together with calcium.
Dosage for people with an underactive parathyroid should be determined by a doctor.