Difference Between Vitamin D2 and Vitamin D3

Calciferol, sometimes known as "vitamin D," is widely regarded as a helpful and essential nutrient − however, it is not a vitamin. Vitamin D refers to a group of related compounds called calciferol, namely vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). When exposed to sunlight, all vertebrate skin produces vitamin D3 − invertebrate skin, such as that of fungi and plants, produces vitamin D2.

Children deficient in vitamin D are at risk for rickets, a disorder that softens their bones. Research shows that vitamin D is important not because of any additional health advantages it may bring but rather because individuals with low vitamin D levels are more likely to develop osteomalacia, a painful bone ailment.

What is Vitamin D3?

Human skin may produce sufficient vitamin D3 when exposed to the sun to meet its beneficial needs. On the other hand, the skin is unable to synthesize D3 when exposed to artificially dimmed or clouded versions of the sun.

  • Form − Vitamin D3 is obtained by humans through the sun and from animal products. Foods like fish and eggs provide usable quantities of D3 along with other minerals.

  • Amount − The human body can produce enough vitamin D3 for a full day after only 10 minutes of sun exposure.

  • Health benefits − Vitamin D3 aids in calcium absorption, making it easier for bones to retain their strength in humans.

What is Vitamin D2?

Vitamin D3 is made by the skin of humans and other mammals, while invertebrates like plants and fungi make vitamin D2. Ultraviolet radiation is used to convert fungus into vitamin D2 in a laboratory, and this supplement is then sold to humans.

  • Form − Plant foods and manufactured pill or supplement forms of D2 are both viable sources of the vitamin for humans.

  • Amount − A healthy adult needs 600 International Units (IU) of vitamin D daily from the diet. About 400 international units of vitamin D may be found in a quart of milk.

  • Health benefits − There is some disagreement over whether or not D2 forms of vitamin D are effective, but scientists agree that vitamin D is essential and has many positive health effects. Vitamin D2, whether natural or manufactured, aids in calcium absorption and the development of strong bone.

Structural Differences Vitamin D2 and Vitamin D3

Vitamin D2 and D3 are structurally different from one another due to differences in their respective side chains. D2 has a methyl group on carbon 24 and a double bond between carbons 22 and 23 on its side chain.

Insects, fungi, and plants may all make vitamin D2 (from ergosterol) when exposed to sunlight.

7-dehydrocholesterol interacts with UVB ultraviolet radiation between 270 and 300 nm in the skin, with maximal synthesis happening between 295-297 nm. Sunlight with a UV index greater than 3 contains these wavelengths, as do the UV lights used in tanning salons. Making vitamin D3 in the skin requires a specific sun elevation, which occurs daily in the tropics, daily in the spring and summer in temperate zones, and virtually never in the arctic circles.

Differences Vitamin D2 and Vitamin D3

The following table highlights the major differences between Vitamin D2 and Vitamin D3 −


Vitamin D2

Vitamin D3



Cholecalciferol or calciol


Produced by ultraviolet light in plants and fungi; artificially synthesized.

Originating from the sun's exposure to the skin of vertebrates.


Help in calcium absorption and regulate phosphorous.

Supports calcium absorption, strengthens bones, regulates phosphorous, and prevents rickets and adult osteomalacia


Meats, potatoes, lentils, bananas

Fruits and vegetable





As a general rule, when people talk about vitamins, they're talking about nutrients that the body just doesn't have the resources to create for itself. In spite of its long history of classification as a vitamin, vitamin D3 is today understood to be a hormone rather than a vitamin.

Although vitamin D has not been shown to prevent osteoporosis, it can aid in calcium absorption, making bones stronger and less prone to fractures. Vitamin D has been linked to a reduced risk of developing breast, colon, and prostate cancers in certain research. However, research shows that those with high vitamin D levels are at a greater risk of developing pancreatic cancer. Yet, there have been no high-quality studies demonstrating that vitamin D is particularly useful in preventing cancer.

Updated on: 31-Jan-2023


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