Which Vitamin D is from Animals? A Guide to D3 and Cholecalciferol

December 26, 2025 •

3 min read

Most people know that vitamin D is vital for bone health, but a lesser-known fact is that it comes in two primary forms: Vitamin D2 and Vitamin D3. Answering the question of which vitamin D is from animals is simple—the animal-derived version is D3, also known as cholecalciferol.

Quick Summary

Vitamin D3 (cholecalciferol) originates from animal-based sources, including fatty fish, liver, and egg yolks, as well as being synthesized in the skin. The alternative, Vitamin D2, is plant-based.

Key Points

Animal-sourced Vitamin D is D3 (Cholecalciferol): This form is found in foods like fatty fish, fish liver oils, and egg yolks.
D3 Synthesis is Triggered by Sunlight: The human body and other vertebrates produce Vitamin D3 in the skin when exposed to UVB radiation.
Many D3 Supplements Come from Lanolin: A common source for commercial Vitamin D3 supplements is lanolin, a wax derived from sheep's wool.
Plant-based Vitamin D is D2 (Ergocalciferol): This form is found in some plants and fungi, particularly mushrooms exposed to UV light.
D3 is Often More Effective for Supplementation: Research suggests that Vitamin D3 is more potent than D2 at increasing and maintaining blood vitamin D levels.

Understanding the Two Main Types of Vitamin D

Vitamin D is a crucial fat-soluble vitamin that plays a significant role in absorbing calcium and maintaining healthy bones and teeth. It is also essential for a properly functioning immune system and helps with muscle function. However, the term "vitamin D" actually refers to a group of related nutrients, with the two most prominent forms being Vitamin D2 (ergocalciferol) and Vitamin D3 (cholecalciferol).

While the human body can utilize both forms, they differ fundamentally in their origins. This distinction is particularly important for those following plant-based diets or seeking clarity on their nutritional intake.

Vitamin D3: The Animal-Sourced Form

If you are wondering which vitamin D is from animals, the answer is Vitamin D3. This form is synthesized in the skin of vertebrates, including humans, when exposed to ultraviolet B (UVB) radiation from sunlight. It is also naturally present in a select number of animal-based foods, making it a key component of many non-vegan diets.

Common Animal-Based Sources of D3:

Fatty Fish and Fish Liver Oil: This is one of the richest natural sources. Options include salmon, trout, mackerel, sardines, and cod liver oil.
Egg Yolks: The yolks of eggs contain a small, but useful amount of vitamin D3.
Beef Liver: This organ meat is another natural source, albeit with smaller amounts of the vitamin.
Cheese: Some types of cheese contain small quantities of vitamin D3.

The Production of Vitamin D3 Supplements

For many people, particularly in regions with limited sunlight, supplements are an essential way to maintain adequate vitamin D levels. Interestingly, many vitamin D3 supplements are not derived directly from food but from a substance called lanolin, which is a wax extracted from sheep's wool. The lanolin is exposed to UVB light to produce cholecalciferol. For individuals following vegan diets, specialized vegan-friendly D3 supplements are available, typically sourced from lichen.

Vitamin D2: The Plant-Based Alternative

In contrast to D3, Vitamin D2, or ergocalciferol, is synthesized by plants and fungi, like mushrooms, upon exposure to ultraviolet light. Because commercially grown mushrooms are often cultivated in the dark, some are intentionally treated with UV light to increase their vitamin D2 content. Fortified foods, including many cereals, plant-based milks (such as soy, almond, and oat), and some orange juices, also commonly contain added Vitamin D2.

Comparison of Vitamin D2 and Vitamin D3

While both forms of vitamin D are absorbed by the body, research suggests that Vitamin D3 is generally more effective at raising and sustaining blood vitamin D levels over time. This difference in potency is one of the key factors to consider when choosing a supplement, though individual dietary needs and preferences are also important.


Feature	Vitamin D2 (Ergocalciferol)	Vitamin D3 (Cholecalciferol)
Primary Source	Plants, fungi (e.g., UV-treated mushrooms), fortified foods	Animals (including humans), fatty fish, eggs, and liver
Efficacy	Less effective at raising and maintaining blood vitamin D levels compared to D3	More effective at raising and maintaining blood vitamin D levels
Supplement Origin	Manufactured from UV-irradiated yeast	Typically from lanolin (sheep's wool) or lichen for vegan versions
Primary Dietary Source	Fortified cereals and plant milks	Fatty fish, fish liver oils, and egg yolks

Conclusion: Making Informed Choices

For those wondering which vitamin D is from animals, the answer is cholecalciferol, or Vitamin D3. This form is found naturally in animal products and is also synthesized in human skin with sun exposure. While Vitamin D2 serves as a plant-based alternative found in some mushrooms and fortified foods, Vitamin D3 is widely considered more potent for supplementation purposes.

Understanding the distinction between these two forms allows consumers to make informed decisions about their dietary and supplement choices based on their health goals and lifestyle. It is always wise to discuss your vitamin D intake with a healthcare provider to ensure you are meeting your specific needs, especially if you have a deficiency or follow a specialized diet.

This article is for informational purposes only and is not a substitute for professional medical advice. For personalized health guidance, consult a healthcare provider.

Frequently Asked Questions

Fatty fish such as salmon, trout, and mackerel are among the richest natural sources of Vitamin D3. Fish liver oils, like cod liver oil, also provide very high concentrations.

While animal products are the only natural food source of Vitamin D3, few foods contain high amounts. It is often difficult to get enough from diet alone, especially during seasons with limited sun exposure.

Most commercial Vitamin D3 supplements are derived from lanolin, a wax from sheep's wool. The lanolin is irradiated with UVB light to produce the cholecalciferol.

Vitamin D2 (ergocalciferol) is the plant-based alternative, produced in some plants and fungi, such as mushrooms, upon exposure to UV light.

Many studies suggest that Vitamin D3 is more effective than D2 at raising and maintaining blood levels of vitamin D. For supplementation, D3 is often the preferred choice.

Since few foods naturally contain significant vitamin D, fortification helps increase dietary intake and prevent deficiency. Common fortified items include milk, cereals, and some plant-based milks.

Yes, vegans can find supplements containing Vitamin D3 derived from non-animal sources, most commonly lichen. They can also rely on Vitamin D2 from fortified foods and UV-treated mushrooms.