What is the Technical Name for Vitamin D3?

January 10, 2026 •

3 min read

According to the National Institutes of Health, vitamin D deficiency is a widespread issue, and the best way to address it depends on several factors. One of the most important forms of this nutrient is vitamin D3, which has a specific technical or scientific name that helps distinguish it from other vitamin D types.

Quick Summary

The technical name for vitamin D3 is cholecalciferol. This article details its functions in the body, its natural and supplemental sources, and explains the key distinctions between vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol).

Key Points

Cholecalciferol is the technical name: The scientific name for vitamin D3 is cholecalciferol, a fat-soluble secosteroid essential for human health.
D3 is more effective than D2: Research suggests that cholecalciferol (D3), primarily from animal sources, is more effective at raising and sustaining blood vitamin D levels than ergocalciferol (D2), which comes from plants.
Sunlight is a key source: The skin produces cholecalciferol when exposed to UVB radiation, though factors like latitude, skin tone, and season affect production.
Functions go beyond bone health: Beyond regulating calcium and phosphorus for bone strength, cholecalciferol supports the immune system, cell growth, and nervous system function.
Deficiency is common but preventable: A widespread deficiency can be addressed through dietary sources like fatty fish, fortified foods, and supplements, which are often the most reliable option.
Activation happens in the liver and kidneys: Before it can be used by the body, cholecalciferol is metabolized in the liver to calcifediol and then activated in the kidneys to calcitriol.

The Scientific Identity of Cholecalciferol

The scientific name for vitamin D3 is cholecalciferol. This fat-soluble secosteroid is vital for human health, particularly its role in calcium and phosphorus absorption for strong bones. Cholecalciferol is produced in the skin upon exposure to UVB sunlight and is found in animal-based foods. Its plant-based counterpart is vitamin D2, or ergocalciferol. While both forms are available in supplements and fortified foods, D3 is considered more effective in raising and maintaining active vitamin D levels over time. The body converts cholecalciferol into its active form, calcitriol, through processes in the liver and kidneys.

The Process of Vitamin D Synthesis and Activation

Skin Synthesis: UVB light exposure converts 7-dehydrocholesterol in the skin to pre-vitamin D3.
Conversion to Cholecalciferol: Pre-vitamin D3 becomes cholecalciferol (vitamin D3) through isomerization.
Liver Metabolism: In the liver, cholecalciferol is hydroxylated to 25-hydroxyvitamin D3 (calcifediol), the main circulating form.
Kidney Activation: The kidneys convert calcifediol into the active hormone, 1,25-dihydroxyvitamin D3 (calcitriol), which regulates calcium absorption and bone health.

Cholecalciferol vs. Ergocalciferol: A Comparison

Understanding the differences between vitamin D3 and D2 is important, as they differ in origin, efficacy, and stability.


Feature	Vitamin D3 (Cholecalciferol)	Vitamin D2 (Ergocalciferol)
Primary Source	Produced in skin with sun exposure; found in animal products.	Derived from plants and fungi.
Chemical Origin	Synthesized from 7-dehydrocholesterol.	Synthesized from ergosterol.
Effectiveness	Generally more effective at raising and maintaining blood levels.	May be less potent than D3.
Stability	Generally more stable in supplements.	More sensitive to heat and moisture.
Dietary Availability	Primarily from animal-based foods; some fortified foods.	Common in many fortified foods.
Vegan Source	Can be produced from lichen.	Primary plant-based option; supplements often lab-made.

Health Implications of Maintaining Adequate Levels

Adequate cholecalciferol levels are essential for bone health and have broader impacts on the immune system, cell growth, and nervous system. Deficiency can increase the risk of chronic diseases.

Bone and Muscle Health: Crucial for preventing rickets and osteomalacia; supports muscle function.
Immune System Support: Helps modulate the immune system and protect against pathogens. May aid in inflammatory bowel diseases.
Cardiovascular and Metabolic Health: Linked to cardiovascular risk, though intervention trial results are mixed. May influence glucose metabolism.
Brain Function: Emerging research suggests a link between low vitamin D and cognitive decline.

Addressing Vitamin D Needs: Sun, Food, and Supplements

Sunlight, dietary sources, and supplements are ways to get cholecalciferol, but sun exposure alone is often insufficient or unsafe.

Sun Exposure: Moderate sun exposure can boost levels, but varies greatly by factors like location and skin type.
Dietary Sources: Fatty fish, fish liver oils, egg yolks, and beef liver are good sources. Many foods are fortified.
Supplements: Often the most reliable option for sufficient intake. Taking with fat enhances absorption. Look for reputable, third-party tested brands.

Conclusion

The technical name for vitamin D3 is cholecalciferol. It is a critical compound supporting bone health, immune function, and potentially cardiovascular and metabolic wellness. While produced by sun exposure, relying on diet and supplements, especially D3 for its efficacy, is a practical approach for most people to maintain adequate levels. Consulting a healthcare provider is advisable for personalized guidance. For more details on vitamin D, consult resources like the National Institutes of Health.

Frequently Asked Questions

The main difference lies in their origin: vitamin D3 (cholecalciferol) comes from animal sources and sun exposure, while vitamin D2 (ergocalciferol) is derived from plant sources and yeast.

Yes, cholecalciferol is synthesized in the skin when it is exposed to ultraviolet B (UVB) radiation from sunlight.

Studies have shown that vitamin D3 is more effective at increasing blood levels of active vitamin D and maintaining those levels for a longer duration compared to vitamin D2.

The best natural food sources of cholecalciferol are fatty fish (like salmon and mackerel), fish liver oils, egg yolks, and beef liver.

Fortified foods can contain either vitamin D2 or D3, depending on the manufacturer. Vitamin D2 is often used due to its lower cost, while some products specify fortification with D3.

A deficiency can lead to poor calcium and phosphorus absorption, resulting in bone-related issues like rickets in children and osteomalacia or osteoporosis in adults.

Cholecalciferol is biologically inactive until it is converted by the liver into calcifediol and then further converted by the kidneys into its active hormonal form, calcitriol.

No, it is not possible to get vitamin D toxicity from prolonged sun exposure. The body regulates its own production by converting excess pre-vitamin D3 into inactive forms.