How much Vitamin D2 is needed per day?

December 26, 2025 •

4 min read

According to the NIH, an estimated 1 billion people worldwide have inadequate levels of vitamin D in their blood, making it crucial to understand how much Vitamin D2 is needed per day to support bone health and overall bodily functions. Unlike vitamin D3, the D2 form is derived from plant sources and fortified foods, which is particularly relevant for those on vegan or vegetarian diets.

Quick Summary

Adults generally need 600-800 IU of vitamin D daily, which can be met with the D2 form from fortified plant-based foods and supplements. Dietary needs vary by age, sun exposure, and health, and plant-derived D2 is an effective way for many, especially vegans, to maintain adequate vitamin levels. While D3 is often more potent, D2 is fully absorbed and utilized by the body.

Key Points

Standard RDA: The recommended daily allowance for most adults is 600 IU (15 mcg), increasing to 800 IU for those over 70.
Plant-Based Source: Vitamin D2 (ergocalciferol) is the form of vitamin D found in plants and yeast, making it a primary option for vegans.
Less Potent Than D3: Studies suggest D3 is more effective at raising and maintaining blood vitamin D levels over time, but D2 is still a valid source.
Dietary Sources: D2 can be found in UV-treated mushrooms and fortified foods like plant-based milks, cereals, and orange juice.
Risk Factors: Factors such as age, skin tone, limited sun exposure, and obesity can increase an individual's daily vitamin D requirements.
Upper Intake Level: To avoid toxicity from supplements, most adults should not exceed 4,000 IU (100 mcg) of vitamin D daily unless medically advised.

Understanding the Recommended Daily Intake for Vitamin D2

The recommended dietary allowance (RDA) for vitamin D—which includes both D2 (ergocalciferol) and D3 (cholecalciferol)—is determined by factors such as age and life stage. For most healthy individuals, the recommended amount is the same regardless of which form of vitamin D they consume, though D3 is considered more effective at raising blood levels long-term. For those who follow a vegan or vegetarian diet, vitamin D2 from plant-based sources or supplements is the primary way to meet these needs, as D3 is typically derived from animal products.

Recommended Daily Intake (RDA) for Vitamin D

The following guidelines from the NIH Office of Dietary Supplements show the general recommended daily amounts for total vitamin D intake, assuming minimal sun exposure:

Infants (0–12 months): 400 IU (10 mcg) daily.
Children (1–13 years): 600 IU (15 mcg) daily.
Teens (14–18 years): 600 IU (15 mcg) daily.
Adults (19–70 years): 600 IU (15 mcg) daily.
Adults (71+ years): 800 IU (20 mcg) daily.
Pregnant and Lactating People: 600 IU (15 mcg) daily.

How Dietary Choices Influence Vitamin D2 Needs

For those relying on plant-based sources, meeting the RDA for vitamin D2 requires careful attention to diet. This is because fewer foods naturally contain D2 compared to D3. Vegans can obtain D2 from UV-treated mushrooms and fortified products. However, the vitamin D content in these foods can vary greatly, making supplementation a common and reliable route to ensure adequate intake.

Factors Affecting Your Vitamin D Requirements

Several variables can influence an individual's specific vitamin D needs, potentially requiring a higher intake than the general RDA:

Age: As people age, the skin's ability to synthesize vitamin D from sunlight decreases, and the kidneys may not be as efficient at converting it to its active form.
Geographic Location: People living far from the equator receive less direct sunlight, especially during winter, impacting natural vitamin D production.
Skin Pigmentation: Individuals with darker skin have more melanin, which acts as a natural sunscreen and reduces the skin's ability to produce vitamin D from sunlight.
Obesity: Body fat can sequester vitamin D, making it less available to the bloodstream and potentially requiring higher intake to maintain adequate levels.
Health Conditions: Certain medical conditions, such as Crohn's disease, celiac disease, or liver and kidney issues, can impair the body's ability to absorb or activate vitamin D.

Comparison of Vitamin D2 vs. D3

While both forms serve the same primary function, they differ in origin and potency. The table below outlines the key differences to help you make an informed choice:


Feature	Vitamin D2 (Ergocalciferol)	Vitamin D3 (Cholecalciferol)
Primary Source	Plants (fungi, yeast), Fortified foods	Sunlight, Animal sources (fatty fish, eggs), Lichen
Production	UV irradiation of ergosterol in yeast	Conversion of cholesterol in skin via sunlight
Potency & Efficacy	Less potent; may raise blood levels less effectively and for a shorter duration than D3.	More potent and effective at raising and maintaining blood vitamin D levels.
Common Users	Primarily vegans, vegetarians, and those seeking plant-based supplements.	Most people, including supplements derived from animal sources.

Sourcing Your Daily Vitamin D2 Intake

For those who specifically need or prefer vitamin D2, here are some key sources to focus on:

UV-Treated Mushrooms: Some mushrooms, like white button or portobello, are exposed to ultraviolet light to boost their D2 content. Always check the packaging for confirmation.
Fortified Plant-Based Milks: Many brands of soy, almond, oat, and other plant-based milks are fortified with vitamin D2.
Fortified Cereals and Orange Juice: Check the nutrition labels on cereals and orange juice, as many are fortified with D2 to help consumers meet their daily requirements.
Dietary Supplements: Vitamin D2 supplements are widely available in various forms, such as capsules or liquid drops. Vegans should specifically look for supplements containing D2 or D3 derived from lichen.

How to Avoid Vitamin D Toxicity

While rare from food sources, vitamin D toxicity can occur from over-supplementation. The Tolerable Upper Intake Level (UL) for adults aged 9+ is 4,000 IU (100 mcg) daily. Consuming more than this amount over a prolonged period can lead to hypercalcemia, a dangerous buildup of calcium in the blood. It is always best to consult a healthcare professional before starting high-dose vitamin D supplements to ensure safety and appropriateness for your individual health status. More information on supplement quality and safety guidelines.

Conclusion

The question of how much Vitamin D2 is needed per day has a standard answer based on general RDAs, but individual circumstances are key. Most healthy adults require 600-800 IU daily, and D2 is an effective way for those on plant-based diets to meet this need. By incorporating fortified foods and, if necessary, responsibly sourced supplements, you can maintain adequate vitamin D levels and support your overall health. Always consider your specific factors and consult with a medical professional for personalized advice, especially if you have underlying health conditions or have a known deficiency. This proactive approach ensures you receive the correct dosage for your body’s unique requirements.

Frequently Asked Questions

A typical adult aged 19 to 70 needs 600 IU (15 mcg) of vitamin D daily, which can be met with either D2 or D3. This recommendation increases to 800 IU for adults over 70.

The main difference is their source and potency. Vitamin D2 is plant-based, while D3 is typically from animal sources or sunlight. D3 is generally considered more effective at raising blood levels for a longer period than D2.

While both D2 and D3 effectively raise vitamin D levels, D3 is often found to be more efficient at raising and maintaining these levels over a longer duration. For many people, especially vegans, D2 supplements are a practical and effective choice.

The best food sources of vitamin D2 include UV-treated mushrooms and fortified foods. Examples are fortified plant milks (soy, almond, oat), fortified orange juice, and some fortified cereals.

Yes. Taking high doses of vitamin D supplements for extended periods can lead to toxicity, resulting in excessive calcium buildup in the blood (hypercalcemia). The Tolerable Upper Intake Level for adults is 4,000 IU (100 mcg) per day.

Vegans have the same RDA for vitamin D as non-vegans (600-800 IU daily), but they rely exclusively on D2 sources like fortified foods or supplements, as they avoid animal-based products that contain D3. Therefore, they must be more mindful of their intake.

Symptoms of deficiency can include fatigue, bone pain, muscle weakness, and frequent infections. The most accurate way to check your vitamin D status is through a blood test ordered by a healthcare provider.