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Difference in Vitamin D2 and Vitamin D3


Vitamin D exists in two main forms: D2 (ergocalciferol) and D3 (cholecalciferol). D2 is produced in plants or mushrooms, while D3 is generated in the skin exposed to sunlight or obtained from animal-based foods. Both forms play a crucial role in calcium absorption and bone health. Notably, D3 is characterized by its natural production in sunlight, and it can also be sourced from animal products such as meat and dairy. Vitamin D contributes not only to bone strengthening but also enhances the immune system. Insufficient intake can lead to issues like osteoporosis.

difference in vitamin d2 and vitamin d3


Vitamin D2(ergocalciferol) and Vitamin D3(cholecalciferol) exist in two main forms, primarily distinguished by their structural differences and sources.


- D2: Mainly obtained from the plants

- D3: It is naturally produced primarily in the skin exposed to sunlight or can be obtained from animal-based foods (meat, dairy products).


- D2: Ergocalciferol has a 22,23-isopropyl structure.

national library of medicine ergocalciferol
National Library of Medicine - Ergocalciferol

- D3: Cholecalciferol has a 22,23-methyl structure.

National Library of Medicine - Cholecalciferol
National Library of Medicine - Cholecalciferol

Biological activity:

- D2: It is generally not considered as active as D3, and existing research suggests it may exhibit lower biological activity than D3.

- D3: It is more effectively utilized in the body than D2 and is considered the primary form of vitamin D.


- D2: Mainly utilized for fortification in foods or as a supplement.

- D3: Primarily obtained through natural sunlight exposure or animal-based foods, commonly used in vitamin D supplements..

Both vitamin D2 and D3 contribute to calcium absorption and bone health in the human body, but D3 is generally known to be more effective in its actions.

Which one is better D2 or D3?

In human physiology, D3 is generally considered to be more effective. This is explained by several reasons:

Biological Activity: D3 is regarded as the primary form of vitamin D, and it is more effectively utilized in the body than D2. D3 undergoes faster conversion in the liver into the active form.

Duration of Action: The effects of D3 may last longer than those of D2. This is attributed to the more prolonged maintenance of D3 in an active form in the plasma.

Natural Production: Human skin can produce D3 when exposed to sunlight. This natural production process supports the unique biological activity of D3.

Research Findings: Some studies suggest that D3 may have more positive effects on various aspects such as bone health, immune enhancement, and inflammation reduction compared to D2.

However, there are situations where D2 is deemed necessary. For instance, some foods may be fortified with D2, and D2 might be recommended in specific dietary plans or medical conditions. Therefore, selecting the appropriate form of vitamin D depends on the context and purpose of supplementation. Generally, absorption through natural sunlight exposure and consumption of animal-based foods tends to favor D3.

Why does the doctors prescribe Vitamin D2?

D3 is generally known to be a more effective form of vitamin D, but there are various reasons why D2 is still prescribed. Physicians may prescribe D2 for several reasons:

Availability and Absorption:

- While D3 is generally more effective than D2, there may be situations where there are no issues with the availability or absorption of D2.


- D2 is typically less expensive to produce and manufacture compared to D3. Especially when produced in large quantities, the cost can be lower.

Food Fortification:

- Some foods are fortified with D2, increasing vitamin D intake and aligning with specific dietary plans or habits.

Special Situations:

- In certain medical conditions or environments, D2 may be a more suitable choice. Depending on a patient's specific condition or medical requirements, a doctor may choose to prescribe D2.

Patient Preference and Compliance:

- Consideration is given to situations where patients find it easier to take and adhere to medications. Some patients may have a preference for D2 for specific reasons.

In the end, the decision of whether to use D2 or D3 is made by considering various factors such as the individual patient's condition, the opinions of medical professionals, cost, patient preferences, and more. While D3 is often more recommended, there are situations where D2 may be the appropriate choice.

Optimal Time for Vitamin D Intake

The optimal time for vitamin D intake can vary depending on various factors. However, there is no specific recommendation for consuming it at a particular time or after a meal. Nevertheless, there are a few considerations:

Sun Exposure:

- One of the most effective ways to obtain vitamin D is exposure to sunlight. When the skin is directly exposed to sunlight, the body produces vitamin D. The duration and method of sunlight exposure vary depending on factors such as season, region, and skin type.

Supplement Intake:

- If taking vitamin D supplements, the intake time can be adjusted freely. Many people prefer to take them with morning or evening meals.

With Fatty Foods:

- Since vitamin D is a fat-soluble vitamin, taking it with fatty foods may enhance absorption. However, it is not necessarily essential, and absorption is generally not an issue when taken with various foods.

In summary, exposure to sunlight is the most effective way to obtain vitamin D, and when taking supplements, it is common to consume them with meals. There are no strict restrictions on specific meal times or food orders. Adjusting the intake time can be done based on individual health conditions and dietary habits.


  1. U.S. Department of Health and Human Services, Office of dietary supplements - vitamin D. NIH Office of Dietary Supplements.

  2. Tripkovic L, Lambert H, Hart K, Smith CP, Bucca G, Penson S, Chope G, Hyppönen E, Berry J, Vieth R, Lanham-New S. Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis. Am J Clin Nutr. 2012 Jun;95(6):1357-64. doi: 10.3945/ajcn.111.031070. Epub 2012 May 2. PMID: 22552031; PMCID: PMC3349454.

  3. Shieh A, Chun RF, Ma C, Witzel S, Meyer B, Rafison B, Swinkels L, Huijs T, Pepkowitz S, Holmquist B, Hewison M, Adams JS. Effects of High-Dose Vitamin D2 Versus D3 on Total and Free 25-Hydroxyvitamin D and Markers of Calcium Balance. J Clin Endocrinol Metab. 2016 Aug;101(8):3070-8. doi: 10.1210/jc.2016-1871. Epub 2016 May 18. PMID: 27192696; PMCID: PMC4971338.

  4. Vitamin D. The Nutrition Source. (2023, March 7).

This content is intended for educational purposes only and is not a substitute for professional medical advice. If you have any questions or concerns about your health, please consult with a healthcare professional.

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