What is the Difference Between Cholecalciferol and Ergocalciferol

The key difference between cholecalciferol and ergocalciferol is their production. Cholecalciferol is produced by the human body as a response to sunlight and is also available through dietary sources, whereas ergocalciferol is not produced in the human body and is created by exposing certain plant-derived materials to UV light.

Cholecalciferol is also known as vitamin D3, while ergocalciferol is also known as vitamin D2. These two are types of vitamins (specifically vitamin D types) and have similar chemical structures as well. Typically, doctors tend to recommend vitamin D2 over vitamin D3 because it is more readily available in higher doses.

CONTENTS

1. Overview and Key Difference
2. What is Cholecalciferol 
3. What is Ergocalciferol
4. Cholecalciferol vs Ergocalciferol in Tabular Form
5. Summary – Cholecalciferol vs Ergocalciferol

What is Cholecalciferol?

Cholecalciferol or vitamin D3 is a form of vitamin D formed from the skin upon exposure to sunlight. It occurs in some foods, and we can take it as a dietary supplement as well. In the skin, cholecalciferol forms due to exposure to UVB light. This substance can be converted into calcitriol in the kidney.

The chemical formula of cholecalciferol is C₂₇H₄₄O. It has a molar mass of 384.648 g/mol. The melting point of this compound ranges from 83 to 86 degrees Celsius, and the boiling point is 496.4 degrees Celsius. When considering the solubility of cholecalciferol in water, it is practically insoluble but freely soluble in ethanol, methanol, and some other organic solvents. Moreover, it is slightly soluble in vegetable oils. This substance is one of the five forms of vitamin D3. It can be categorized as a secosteroid, which is a steroid molecule having one open ring.

When cholecalciferol is taken as it is, it is inactive. It can be converted into its active form through hydroxylation processes. First, hydroxylation occurs in the liver by the action of CYP2R1. This forms 25-hydroxycholecalciferol. The second hydroxylation occurs in the kidney through the action of CYP27B1. This converts the 25-OH into 1,25-dihydroxycholecalciferol. We can find these metabolites in blood. The metabolites are bound to the vitamin D-binding protein. The action of the activated form of cholecalciferol (calcitriol) can be mediated by the vitamin D receptor, a nuclear receptor that can regulate the synthesis of a large number of proteins and is also present virtually in every cell in the body.

What is Ergocalciferol?

Ergocalciferol or vitamin D2 (sometimes calciferol) is a type of vitamin D that can be found in food and is useful as a dietary supplement. It can be used to prevent and treat vitamin D deficiency. Vitamin D deficiency can occur due to poor absorption by the intestine or liver disease. Moreover, we can use this substance to treat low blood calcium levels coming from hypoparathyroidism. It can be used by oral route or injection into a muscle.

The chemical formula of ergocalciferol is C₂₈H₄₄O. The molar mass is 396.659 g/mol. The melting point can range from 114 to 118 degrees Celsius. It can be categorized as a secosteroid that forms from the photochemical bond breakdown of a steroid. This happens specifically from the action of UV light on ergosterol (a form of provitamin D2).

Moreover, ergocalciferol is an inactive substance that requires two hydroxylation steps to become active. The first hydroxylation occurs in the liver in the presence of CYP2R1 to form 25-hydroxyergocalciferol and the second hydroxylation occurs in the liver in the presence of CYP27B1, which gives the active 1,25-dihydroxyergocalciferol.

What is the Difference Between Cholecalciferol and Ergocalciferol?

Cholecalciferol and ergocalciferol are two important secosteroid compounds. The key difference between cholecalciferol and ergocalciferol is that cholecalciferol is produced by the human body as a response to sunlight and is also available through dietary sources, whereas ergocalciferol is not produced in the human body and is created by exposing certain plant-derived materials to UV light.

The below infographic presents the differences between cholecalciferol and ergocalciferol in tabular form for side-by-side comparison.

Summary – Cholecalciferol vs Ergocalciferol

Cholecalciferol or vitamin D3 is a form of vitamin D formed from the skin upon exposure to sunlight, and also it occurs in some foods. Ergocalciferol or vitamin D2 (sometimes calciferol) is a type of vitamin D that can be found in food and is useful as a dietary supplement. The key difference between cholecalciferol and ergocalciferol is that cholecalciferol is produced by the human body as a response to sunlight and whereas ergocalciferol is not produced in the human body.

Reference:

1. Kuncyte, Viktorija. “Using the Best Form of Vitamin D: Ergocalciferol vs Cholecalciferol.” Feel, 24 Jan. 2022.

Image Courtesy:

1. “Cholecalciferol” By Calvero – Own work (made with ChemDraw) (Public Domain) via Commons Wikimedia
2. “Ergocalciferol” By Calvero – Own work (made with ChemDraw) (Public Domain) via Commons Wikimedia