Last modified on October 19th, 2023
If you’re learning more about vitamin D supplements, one big question you might have is the difference between vitamin D2 vs D3. We cover everything you should know about the two.
Key Takeaways About Vitamin D2 vs D3
- Vitamin D is a family of nutrients with shared similarities in structure.
- If you’re getting vitamin D from your diet, your food contains either D2 or D3.
- Researchers believe vitamin D2 is less effective for raising vitamin D blood levels than D3.
- If you’re supplementing, choose vitamin D3 supplements.
The Basics of Vitamin D
Before exploring the specifics of vitamin D2 vs D3, what is vitamin D?
Vitamin D is a fat-soluble vitamin that helps regulate your immune system function and bone growth and helps your body absorb calcium.
When you’re exposed to sunlight, your body can produce vitamin D, but if you live somewhere there’s not a lot of sunlight, it’s winter, or you don’t go outdoors that much, you may need to get vitamin D from your diet or a supplement.
Foods with vitamin D include egg yolk, liver, butter, and fish oils.
Some foods are also fortified with vitamin D, meaning they’re added. This is true of breakfast cereals and milk, for example.
If you’re taking vitamin D as a supplement, keep in mind that it’s fat-soluble.
As such, try to either take your supplement with a meal containing fat or choose an oil-based supplement.
We tend to prefer oil-based liquid vitamin D supplements because they’re easier for your body to absorb.
Vitamin D supplements are available in two forms: vitamin D2 and vitamin D3.
Vitamin D2 is also called ergocalciferol, and D3 is also called cholecalciferol.
An Overview of Vitamin D2 vs D3
The following are some of the primary things to know about the differences and similarities seen when comparing vitamin D2 vs vitamin D3.
What is Vitamin D2?
Vitamin D2, or ergocalciferol, helps your body absorb calcium and phosphorus.
Sources of vitamin D2 include mushrooms, but only if they’re grown in UV light, and fortified foods.
Vitamin D2 is cheaper to make, so it’s often what’s included in vitamin D-fortified foods.
Vitamin D2 comes primarily from plant sources and fortified foods.
If you were to choose a vitamin D2 supplement, there’s concern that it could be lower quality than a D3 supplement.
For example, when comparing vitamin D2 vs D3, vitamin D2 is more susceptible to fluctuations in temperature, so your supplement could degrade faster.
You would need to ensure you were storing a D2 supplement in a cool, dry place and out of direct sunlight.
What is Vitamin D3?
If we compare vitamin D3 vs D2, vitamin D3 is the preferred version to supplement.
When your skin is exposed to sunlight, it makes D3. If you get regular sun exposure, you may not need a D supplement at all.
If you have a vitamin D deficiency and need to supplement, choose vitamin D3.
The primary difference when comparing vitamin D2 vs vitamin D3 is their ability to raise your blood levels of vitamin D.
Both can be absorbed in your bloodstream, but the liver metabolizes them differently.
Your liver will metabolize D2 into something called 25-hydroxyvitamin D2. Your liver metabolizes vitamin D3 into 25-hydroxyvitamin D3.
When vitamin D is circulating in your body, it’s in the form of calcifediol. Your blood levels of calcifediol are how your vitamin D levels are determined.
If you take a D2 supplement, you’re likely going to get less calcifediol in your blood than you would with D3.
Studies show vitamin D3 is the way to go to truly raise your blood levels of vitamin D.
What to Know About Choosing a Vitamin D Supplement
If you need a vitamin D supplement and it’s something your doctor recommends, you should aim to take anywhere from 400 to 800 IU of vitamin D3 a day.
Take your supplement with a food that’s considered a healthy fat, such as avocado, because this will help you absorb it better.
Don’t take more than 4,000 IU of vitamin D a day because it can lead to toxicity.
If you’re 70 or older, you should aim for around 800 IU of vitamin D a day because as you get older, it becomes more difficult for your body to produce and use vitamin D.
It’s also important to understand that vitamin D deficiency is on the rise. This is for many different reasons.
One is that we now protect ourselves from the sun more than ever with sunscreen and coverage, which can reduce our vitamin D production by 95%.
Of course, it’s important to protect yourself from exposure, but at the same time, realize the effects that may have on your vitamin D levels.
If you’re overweight or older, you may also be at greater risk of vitamin D deficiency, as are people with darker skin.
Final Thoughts—Vitamin D2 vs D3
Vitamin D intake is important for all of us, particularly as we head into winter.
Speak to your doctor about whether or not you should take a supplement.
As you choose a vitamin D supplement, you’ll likely see that you have an option between vitamin D2 and D3.
When comparing vitamin D2 vs D3, keep in mind that D3 is better at raising vitamin D levels in your blood. A vitamin D3 supplement will likely be more potent, fast-acting, and generally effective than a D3 supplement.
Vitamin D3 is also higher quality and is what your skin makes in response to sun exposure.
If you have questions about your vitamin D status, speak to your doctor, who can test your levels and help you determine if you need a supplement.
We encourage you to check out our full post on vitamin D supplements.
Frequently Asked Questions: Comparing Vitamin D2 vs Vitamin D3
What are Vitamin D2 and Vitamin D3?
Vitamin D2: Also known as ergocalciferol, Vitamin D2 is a plant-derived form of vitamin D. It is often found in fortified foods and supplements.
Vitamin D3: Vitamin D3, or cholecalciferol, is the natural form of vitamin D produced in the skin when exposed to sunlight. It’s also available as a dietary supplement, typically derived from animal sources.
What are the Main Differences Between Vitamin D2 and Vitamin D3?
The primary difference is their sources: Vitamin D2 is derived from plants, while Vitamin D3 is derived from animal sources and synthesized in the skin through sunlight exposure.
Which Form of Vitamin D is More Effective?
Vitamin D3 is generally considered more effective at raising blood levels of vitamin D and maintaining those levels over time. It has a longer duration of action in the body.
Are There Any Differences in Absorption?
Vitamin D3 is more efficiently absorbed in the body compared to Vitamin D2. This makes it a more preferred choice for supplementation.
Are There Any Dietary Sources for Vitamin D3?
Vitamin D3 is typically not found in significant amounts in food. It is mainly produced in the skin when exposed to UVB sunlight.
How Are They Used in Supplements?
Both Vitamin D2 and Vitamin D3 are available in supplement forms, such as capsules or tablets. They are often used to address vitamin D deficiencies, improve bone health, and support the immune system.
Which Form of Vitamin D is More Common in Fortified Foods?
Vitamin D2 is more commonly used to fortify plant-based and vegan products, while Vitamin D3 is often used in animal-based fortified foods.
Are There Any Dietary Restrictions or Concerns With Vitamin D2 or D3?
Both forms are generally safe when taken within recommended doses. However, if you have specific dietary restrictions or are following a vegan or vegetarian diet, you might prefer Vitamin D2 supplements.
Can I Convert Vitamin D2 to Vitamin D3 in the Body?
While Vitamin D2 can be converted to active forms in the body, this process is less efficient than with Vitamin D3. Therefore, D3 is considered the more effective source.
Which Form Should I Choose for Supplementation?
Vitamin D3 is typically the preferred form for supplementation due to its superior absorption and effectiveness. However, consult with a healthcare professional for personalized recommendations based on your health needs and dietary preferences.
Are There Any Special Considerations for Children, Pregnant Women, or the Elderly?
The choice between Vitamin D2 and D3 can vary based on individual health requirements. Consult with a healthcare provider for tailored advice, especially during pregnancy or for children and the elderly.
Why do doctors prescribe vitamin D2 instead of D3?
Doctors may prescribe Vitamin D2 (ergocalciferol) instead of Vitamin D3 (cholecalciferol) in specific situations, but certain factors and considerations typically influence this choice.
Here are some reasons why doctors might prescribe Vitamin D2:
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Plant-Based or Vegan Diet: Patients who follow plant-based or vegan diets may prefer Vitamin D2, as it is derived from plant sources, making it a more suitable option.
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Religious or Dietary Restrictions: Some individuals have dietary restrictions based on their religious beliefs or personal preferences that may lead them to choose Vitamin D2 over animal-derived Vitamin D3.
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Specific Medical Conditions: In certain medical conditions or treatments, such as kidney disease or kidney transplant patients, Vitamin D2 might be preferred. It can be easier to monitor and manage in these cases.
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Available Formulations: In some regions, Vitamin D2 may be more readily available or affordable, influencing the choice of prescription.
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Medical Professional’s Preference: Individual healthcare providers may have their own preferences or experiences with different forms of vitamin D.
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Historical Practices: Historically, Vitamin D2 was more commonly used for supplementation. While Vitamin D3 is generally considered more effective, some healthcare providers may continue using Vitamin D2 due to familiarity.
It’s important to note that in most cases, Vitamin D3 is considered more effective at raising and maintaining blood levels of vitamin D, and it is the preferred form for supplementation.
However, the choice between Vitamin D2 and D3 should be made based on individual patient needs, dietary preferences, and any underlying health conditions.
Doctors should carefully consider their patients’ specific circumstances and health status when choosing between Vitamin D2 and Vitamin D3 and may perform blood tests to monitor vitamin D levels to ensure that the prescribed form is effective.
Who should not take vitamin D2?
While Vitamin D2 (ergocalciferol) is generally considered safe when taken at appropriate doses, there are certain individuals who should exercise caution or avoid taking it without medical supervision.
Here are some situations in which people should be cautious or avoid Vitamin D2 supplementation:
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Allergic Reactions: If you have a known allergy or hypersensitivity to ergocalciferol or any of the ingredients in Vitamin D2 supplements, you should avoid taking them.
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Hypercalcemia: Individuals with a history of hypercalcemia (elevated levels of calcium in the blood) should be cautious when taking Vitamin D2. It can increase calcium absorption in the intestines, potentially exacerbating hypercalcemia.
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Primary Hyperparathyroidism: People with primary hyperparathyroidism, a condition characterized by overactive parathyroid glands, should avoid Vitamin D2 supplements as they can worsen calcium imbalances.
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Sarcoidosis: Sarcoidosis is a condition that can affect multiple organs, including the lungs and lymph nodes. In some cases, it may cause the body to absorb too much calcium, making Vitamin D2 supplementation risky.
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Kidney Disease: Individuals with kidney disease or impaired renal function may have difficulty converting Vitamin D2 into its active form. They should use Vitamin D supplements under medical guidance.
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Certain Medications: Some medications may interact with Vitamin D2, affecting its absorption or metabolism. Inform your healthcare provider about all the medications you are taking to ensure there are no contraindications.
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Pregnancy and Breastfeeding: While Vitamin D2 is generally considered safe for pregnant and breastfeeding women at recommended doses, it’s essential to follow medical advice to ensure appropriate supplementation and avoid excessive doses.
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Children: Pediatric dosages should be determined by a healthcare provider. It’s crucial to provide age-appropriate Vitamin D supplementation for children and monitor their vitamin D levels.
Always consult with a healthcare professional before taking Vitamin D2 supplements, especially if you have underlying health conditions, are taking medications, or are unsure about the appropriate dosage.
Your healthcare provider can assess your specific needs, monitor your vitamin D levels, and recommend the most suitable form and dosage of Vitamin D based on your individual health circumstances.
Comparison of Vitamin D2 Supplements and Vitamin D3 Supplements: Pros and Cons
Vitamin D2 (Ergocalciferol):
Pros:
- Plant-Based: Vitamin D2 is derived from plant sources, making it suitable for individuals following vegan or vegetarian diets.
- Affordability: It is often more affordable than Vitamin D3, which can be a cost-effective choice for supplementation.
- Widely Available: Vitamin D2 is readily available and may be found in many over-the-counter supplements.
- Physician Preference: Some healthcare professionals prefer prescribing Vitamin D2 for specific medical conditions or in certain situations.
Cons:
- Less Effective: Vitamin D2 is considered less effective at raising and maintaining blood levels of vitamin D compared to Vitamin D3. It has a shorter duration of action.
- Conversion: Vitamin D2 must be converted in the body to its active form (calcitriol), a process that is less efficient than the conversion of Vitamin D3.
- Dose Requirement: A higher dose of Vitamin D2 may be needed to achieve the same results as a lower dose of Vitamin D3.
- Limited Sunlight Conversion: Vitamin D2 is not produced naturally in the skin upon exposure to sunlight, unlike Vitamin D3.
Vitamin D3 (Cholecalciferol):
Pros:
- More Effective: Vitamin D3 is generally more effective at raising and maintaining optimal blood levels of vitamin D.
- Efficient Conversion: It is readily converted into its active form (calcitriol) in the body, providing quicker results.
- Longer Duration: Vitamin D3 has a longer half-life in the body, which means it remains active for an extended period.
- Sunlight Conversion: Vitamin D3 is naturally synthesized in the skin upon exposure to UVB sunlight.
Cons:
- Animal Source: Vitamin D3 is typically derived from animal sources, which may not be suitable for those following strict vegan or vegetarian diets.
- Cost: It is often more expensive than Vitamin D2 supplements.
Summary:
Effectiveness: Vitamin D3 is generally considered more effective and efficient at raising and maintaining blood levels of vitamin D compared to Vitamin D2.
Dietary Preferences: Vitamin D2 is suitable for individuals with dietary preferences such as vegans and vegetarians, while Vitamin D3 is primarily derived from animal sources.
Cost: Vitamin D2 is often more affordable, making it a cost-effective choice. However, the cost difference may not be substantial.
Conversion and Duration: Vitamin D3 requires less conversion in the body and has a longer duration of action, which makes it the preferred choice for many health professionals.
In most cases, healthcare providers prefer prescribing Vitamin D3 due to its superior effectiveness and efficiency. However, individual dietary preferences, medical conditions, and healthcare provider recommendations can influence the choice between Vitamin D2 and Vitamin D3. It’s essential to consult with a healthcare professional for personalized advice and to determine the most suitable form and dosage of Vitamin D based on individual health needs and circumstances.
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