Which is better for you, vitamin D2 or D3?

November 19, 2025 •

4 min read

Studies suggest that Vitamin D3 is more effective at raising and maintaining overall vitamin D levels in the body than vitamin D2. While both forms are crucial for bone health and immune function, their distinct sources and metabolic pathways lead to notable differences in potency and efficacy.

Quick Summary

This article compares vitamin D2 and D3, detailing their sources, how the body processes them, and recent research on their effectiveness in increasing vitamin D levels. It provides a comparative table, covers dietary considerations, and outlines which supplement may be preferable based on individual health needs or dietary choices.

Key Points

Sources differ: Vitamin D2 comes from plants (e.g., mushrooms), while D3 is from animal sources (e.g., fatty fish, eggs) and synthesized in human skin.
Potency favors D3: Studies show that vitamin D3 is more effective at raising and maintaining blood vitamin D levels than D2.
Metabolism varies: The body metabolizes vitamin D3 more efficiently than D2, leading to higher and longer-lasting concentrations in the blood.
D3 is more stable: D3 supplements tend to be more stable and have a longer shelf life than D2, which is more sensitive to environmental factors.
Dietary considerations: For vegans and vegetarians, D2 is a suitable plant-based option, though new vegan D3 supplements from lichen are also available.
Consult a professional: For managing a deficiency, a healthcare provider can recommend the appropriate form and dosage of vitamin D.

Understanding the Basics: Vitamin D2 vs. D3

Both vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol) are essential, fat-soluble nutrients that support vital bodily functions, including calcium absorption and immune regulation. The primary distinction lies in their origins: D2 is plant-based, derived from the UV irradiation of yeast, while D3 is sourced from animals or synthesized in human skin upon exposure to sunlight. This fundamental difference in their source affects how the body processes and utilizes each form.

The Source and Synthesis of Each Vitamin

Vitamin D3 is the form naturally produced by the human body. When skin is exposed to ultraviolet B (UVB) radiation from the sun, it triggers a conversion process that turns a precursor compound, 7-dehydrocholesterol, into cholecalciferol. Animal-based foods like fatty fish, egg yolks, and liver also contain significant amounts of D3. In contrast, vitamin D2 is found in plants and fungi, particularly mushrooms exposed to UV light. Because D2 is cheaper to produce, it is often used in fortified foods such as cereals, orange juice, and plant-based milks.

How the Body Utilizes D2 vs. D3

After ingestion, both vitamin D2 and D3 are absorbed in the small intestine and sent to the liver for conversion into a circulating form known as calcifediol. It is at this stage that a difference in potency becomes apparent. Research indicates that the body metabolizes D3 more efficiently, leading to a higher concentration and longer maintenance of calcifediol in the bloodstream compared to D2. This difference suggests D3 may be more effective for improving overall vitamin D status, particularly for sustained supplementation.

Recent Clinical Evidence on Effectiveness

Numerous clinical studies have investigated the relative efficacy of vitamin D2 versus D3, with most evidence pointing toward D3's superiority. A 2024 meta-analysis, examining daily doses across 20 studies, found that vitamin D3 was more effective than D2 at raising total blood 25(OH)D levels. A 2012 meta-analysis also indicated that D3 is more efficacious at raising serum 25(OH)D concentrations. While some earlier research found similar results with daily low doses, the consensus from recent, larger studies favors D3 for improving vitamin D status. This is particularly true when comparing bolus doses, where D3 shows a significantly stronger effect.

Comparison Table: Vitamin D2 vs. D3


Feature	Vitamin D2 (Ergocalciferol)	Vitamin D3 (Cholecalciferol)
Primary Source	Plants and fungi, such as UV-exposed mushrooms, and many fortified foods.	Animal products like fatty fish, egg yolks, and liver; also synthesized in human skin via sunlight. Vegan D3 from lichen is also available.
Effectiveness	Less potent at raising blood vitamin D levels, and has a shorter duration of action.	More potent and effective at increasing and sustaining blood vitamin D levels.
Processing in Body	Metabolized less efficiently in the liver, yielding less calcifediol compared to D3.	Metabolized more efficiently in the liver, leading to higher, more stable blood levels.
Stability	More sensitive to heat and humidity, which can affect its shelf life.	Generally more stable, resulting in a longer shelf life.
Suitability	An effective option for vegans and vegetarians, though some newer vegan D3 supplements exist. Can be prescribed in high doses to treat deficiency.	The preferred supplemental form for most people seeking to optimize vitamin D levels due to higher potency.

Considerations for Choosing a Supplement

For most individuals, particularly those needing to correct a vitamin D deficiency, a D3 supplement is the superior choice due to its higher potency and longer-lasting effects. However, dietary preferences play a significant role. Vegans or vegetarians, for instance, might opt for a plant-based D2 supplement or a newer vegan-friendly D3 derived from lichen. Additionally, some high-dose prescription supplements for severe deficiencies are formulated with D2. For individuals with a higher body mass index (BMI), some studies suggest the potency difference between D2 and D3 is less pronounced, as excess body fat may affect the metabolism of both forms similarly. Therefore, consultation with a healthcare provider is essential to determine the best course of action.

Conclusion

Ultimately, while both vitamin D2 and D3 are forms of the essential vitamin, D3 is generally more effective for raising and maintaining blood vitamin D levels over time. Its animal-based origins, combined with its efficient metabolism by the body, give it an edge in terms of potency and stability. For most people, opting for a D3 supplement is the best way to address or prevent a deficiency, though specific dietary choices or therapeutic needs may lead to considering D2. The final decision should be guided by a discussion with a healthcare professional, factoring in individual health status and dietary habits. Further research continues to clarify the nuanced effects of both forms on various health outcomes.

Frequently Asked Questions

While most recent research suggests vitamin D3 is more effective at raising and maintaining blood vitamin D levels, the choice depends on individual factors like diet and severity of deficiency.

Vegans and vegetarians can take vitamin D2, which is plant-based, or choose newer D3 supplements that are derived from lichen.

A blood test measuring your 25-hydroxy vitamin D levels can determine if you have a deficiency. Based on the results, a healthcare professional can advise if supplementation is necessary.

Many fortified foods, such as milk, cereal, and plant-based milks, often use the cheaper-to-produce vitamin D2. However, some may use D3.

Sun exposure is a primary source of vitamin D3, but factors like latitude, season, skin tone, and sunscreen use can limit synthesis. Many people, especially in less sunny regions, rely on food or supplements.

Both forms are absorbed and processed by the liver, but D3 is metabolized more efficiently, resulting in higher and more stable circulating vitamin D levels.

No, high-dose prescriptions can be either D2 or D3. In the past, D2 was often used for high-dose treatments, but D3 is also prescribed, especially given its proven efficacy.