500px
Vitamin D2 supplements

Ergocalciferol may be used as a vitamin D supplement, whereas cholecalciferol (vitamin D3) is produced naturally by the skin when exposed to ultraviolet light.

- Ergocalciferol

There are conflicting reports concerning the relative effectiveness of cholecalciferol (D3) versus ergocalciferol (D2), with some studies suggesting less efficacy of D2, and others showing no difference.

- Cholecalciferol

6 related topics

Alpha

Cholecalciferol (D3)

Vitamin D

Group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and many other biological effects.

Group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and many other biological effects.

Cholecalciferol (D3)
Calcium regulation in the human body. The role of active vitamin D (1,25-dihydroxyvitamin D, calcitriol) is shown in orange.
Global vitamin D serum levels among adults (nmol/L).
The photochemistry of vitamin D biosynthesis in animal and fungi
Thermal isomerization of previtaminD3 to vitamin D3
In the epidermal strata of the skin, vitamin D production is greatest in the stratum basale (colored red in the illustration) and stratum spinosum (colored light brown).
Liver hydroxylation of cholecalciferol to calcifediol
Kidney hydroxylation of calcifediol to calcitriol

In humans, the most important compounds in this group are vitamin D3 (also known as cholecalciferol) and vitamin D2 (ergocalciferol).

A representation of the 3D structure of the protein myoglobin showing turquoise α-helices. This protein was the first to have its structure solved by X-ray crystallography. Toward the right-center among the coils, a prosthetic group called a heme group (shown in gray) with a bound oxygen molecule (red).

Vitamin D-binding protein

Protein that in humans is encoded by the GC gene.

Protein that in humans is encoded by the GC gene.

A representation of the 3D structure of the protein myoglobin showing turquoise α-helices. This protein was the first to have its structure solved by X-ray crystallography. Toward the right-center among the coils, a prosthetic group called a heme group (shown in gray) with a bound oxygen molecule (red).

It is able to bind the various forms of vitamin D including ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3), the 25-hydroxylated forms (calcifediol), and the active hormonal product, 1,25-dihydroxyvitamin D (calcitriol).

Conversion of cholecalciferol to calcidiol as catalyzed by CYP2R1.

CYP2R1

Cytochrome P450 2R1, an enzyme which is the principal vitamin D 25-hydroxylase.

Cytochrome P450 2R1, an enzyme which is the principal vitamin D 25-hydroxylase.

Conversion of cholecalciferol to calcidiol as catalyzed by CYP2R1.

It has 25-hydroxylase activity, which converts cholecalciferol (vitamin D3) into calcifediol (25-hydroxyvitamin D3, also known as calcidiol), the major circulatory form of the vitamin.

CYP2R1 will also hydroxylate ergocalciferol (vitamin D2), derived from dietary sources, into 25-hydroxyvitamin D2 (ercalcidiol).

The normal process of Vitamin D absorption

Vitamin D deficiency

Defined as a vitamin D level that is below normal.

Defined as a vitamin D level that is below normal.

The normal process of Vitamin D absorption
226x226px
Normal bone vs. Osteoporosis
Child with rickets
Vitamin D2 supplements

Since vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol) are fat-soluble, humans and other animals with a skeleton need to store some fat.

Calcitriol

Active form of vitamin D, normally made in the kidney.

Active form of vitamin D, normally made in the kidney.

Calcitriol synthesis

Compared to other vitamin D compounds in clinical use (cholecalciferol, ergocalciferol), calcitriol has a higher risk of inducing hypercalcemia.

2017 marked the 40th anniversary of the WHO Model List of Essential Medicines.

WHO Model List of Essential Medicines

The WHO Model List of Essential Medicines (aka Essential Medicines List or EML ), published by the World Health Organization (WHO), contains the medications considered to be most effective and safe to meet the most important needs in a health system.

The WHO Model List of Essential Medicines (aka Essential Medicines List or EML ), published by the World Health Organization (WHO), contains the medications considered to be most effective and safe to meet the most important needs in a health system.

2017 marked the 40th anniversary of the WHO Model List of Essential Medicines.
A skeletal model of the chemical structure of aspirin
A skeletal model of the chemical structure of albendazole
Pure crystals of ethambutol
Two capsules of atazanavir
Bag containing one unit of fresh frozen plasma
A vial of oral cholera vaccine

Colecalciferol

Ergocalciferol