What Is Another Name for Cholecalciferol? (It's Vitamin D3)

January 9, 2026 •

3 min read

According to the National Institutes of Health, the majority of evidence indicates that cholecalciferol (vitamin D3) is more effective than ergocalciferol (vitamin D2) in increasing and maintaining serum 25(OH)D levels. Cholecalciferol is the common name for vitamin D3, a vital nutrient produced in the skin upon sun exposure and found in some foods.

Quick Summary

Cholecalciferol is also known as vitamin D3, a fat-soluble vitamin essential for calcium absorption, bone health, and immune function. It differs from the plant-derived vitamin D2 and can be obtained from sunlight, animal-based foods, and supplements.

Key Points

Identity: Cholecalciferol is another name for Vitamin D3.
Synthesis: The body naturally produces cholecalciferol in the skin when exposed to UVB sunlight.
Sources: Beyond sun exposure, cholecalciferol comes from fatty fish, egg yolks, beef liver, and fortified foods like milk.
D3 vs D2: Compared to the plant-based vitamin D2, cholecalciferol (D3) is generally more effective at raising and sustaining blood vitamin D levels.
Function: It is essential for calcium absorption, bone mineralization, immune system regulation, and muscle function.
Deficiency: A lack of cholecalciferol can lead to serious bone conditions like rickets and osteomalacia.

Cholecalciferol: The 'Sunshine Vitamin' Explained

Cholecalciferol is the scientific name for vitamin D3. Vitamin D3 is the form of vitamin D produced by the human body when skin is exposed to UVB radiation from sunlight. It's a crucial nutrient or prohormone that regulates calcium and phosphate balance, vital for bone health and various metabolic functions. While cholecalciferol is a scientific term, vitamin D3 is commonly used for supplements and fortified foods.

How the Body Synthesizes and Uses Cholecalciferol

Vitamin D3 production starts in the skin when UVB light hits 7-dehydrocholesterol, creating cholecalciferol. This is then sent to the liver and converted to 25-hydroxyvitamin D3 (calcifediol), which is measured to check vitamin D levels. The kidneys then convert calcifediol into 1,25-dihydroxyvitamin D3 (calcitriol), the active form. Calcitriol boosts calcium absorption in the gut and manages blood calcium levels.

Sources of Cholecalciferol

Sunlight is a key source, but factors like location, season, clouds, and skin color affect D3 synthesis. Other sources are important.

Fatty Fish: Salmon, mackerel, trout, and sardines are rich sources. Cod liver oil is also high in D3.
Animal Products: Beef liver, egg yolks, and cheese also contain cholecalciferol.
Fortified Foods: Many foods like milk, cereals, and some orange juices are fortified with vitamin D3.
Supplements: D3 supplements are available in various forms and often recommended for those with limited sun exposure or deficiency.
Lichen-Based D3: Vegan cholecalciferol options derived from lichen are also available.

Comparing Cholecalciferol (Vitamin D3) and Ergocalciferol (Vitamin D2)

D3 (cholecalciferol) and D2 (ergocalciferol) are different forms of vitamin D. The table below outlines their main distinctions.


Feature	Cholecalciferol (Vitamin D3)	Ergocalciferol (Vitamin D2)
Primary Source	Animal sources and sun exposure	Plant sources and fortified foods
Chemical Composition	From 7-dehydrocholesterol	From ergosterol
Potency	More effective at increasing and maintaining blood vitamin D	Less potent with shorter action
Efficacy	Studies suggest better improvement in vitamin D status and PTH regulation	Lower efficacy, but effective at lower doses
Stability	More stable for food fortification	Less stable
Suitability for Vegans	Traditionally animal, but lichen-based exists	Naturally from plants/fungi, suitable for vegans

Benefits of Maintaining Adequate Cholecalciferol Levels

Sufficient cholecalciferol is vital for health, extending beyond bone health.

Bone Health: Enhances calcium absorption, key for strong bones. Deficiency can cause rickets, osteomalacia, or osteoporosis.
Immune System Support: Modulates immune responses against infections.
Mental Health: Linked to reduced risk of depression and anxiety.
Muscle Function: Important for muscle strength and contraction.
Cardiovascular Health: Associated with lower risk of heart disease and blood pressure regulation.

Conclusion: The Importance of Cholecalciferol

Cholecalciferol, or vitamin D3, is a critical fat-soluble vitamin. It's made in the body via sun exposure but also found in food and supplements. D3 is often preferred for supplementation due to its effectiveness in raising vitamin D levels compared to D2. Adequate intake supports bone health, immunity, and overall vitality, particularly for those with limited sun exposure. If concerned about levels, a healthcare provider can help with a blood test. For more information, the National Institutes of Health provides extensive research on vitamin D.

Frequently Asked Questions

The primary difference is their source and potency. Cholecalciferol (D3) is animal-derived or produced in the skin, while ergocalciferol (D2) comes from plants and fungi. D3 is generally more effective at raising and sustaining blood vitamin D levels.

Individuals with limited sun exposure, darker skin, older adults, and those with certain medical conditions are at a higher risk of deficiency. A doctor can perform a blood test to check your vitamin D levels and determine if supplementation is necessary.

Yes, while most cholecalciferol is animal-derived, some manufacturers now offer vegan-friendly supplements sourced from lichen.

Common symptoms include fatigue, bone and muscle pain, muscle weakness, and mood changes. In severe cases, it can lead to bone diseases like rickets or osteomalacia.

Depending on your location, time of year, and skin type, relying solely on sun exposure can be difficult. Sunscreen use also blocks the UVB rays needed for synthesis. Combining sun exposure with dietary sources or supplements is often necessary.

Yes, excessive intake of supplements can lead to vitamin D toxicity (hypervitaminosis D), which can cause abnormally high calcium levels in the blood. This can result in side effects like nausea, vomiting, and kidney issues.

The body converts cholecalciferol into its active hormone form, calcitriol. Calcitriol then binds to vitamin D receptors in the intestines, signaling the body to absorb more calcium and phosphorus from the food you eat.