What is the Difference Between Vitamin D And D3?

Estimated Reading Time: 6 minutes

Published on: 10 Nov 2025

You’ve probably heard people say they’re taking “Vitamin D,” but then the label says “D3.” Confusing, right? It’s a small detail that throws a lot of people off.

Whether you’re choosing a supplement, correcting a deficiency, or just curious about what your body really needs, understanding the difference in the vitamin D vs D3 debate can make a big impact.

So, let’s break down the real difference between vitamin D and D3.

First Things First: What Is Vitamin D?

Vitamin D is a fat-soluble vitamin that’s essential for several critical bodily functions. It helps your body absorb calcium and phosphorus—two minerals vital for strong bones and teeth. It also plays a role in:

Immune system regulation

Muscle function

Inflammatory response

Cardiovascular health

Interestingly, vitamin D is technically not a vitamin in the traditional sense—it behaves more like a hormone.

There are two main forms:

Vitamin D2

Vitamin D3

Now, this is where the real vitamin D vs D3 comparison begins to matter.

Vitamin D vs D3: The Big Difference

Here’s what separates Vitamin D2 from D3 at a glance:

Feature	Vitamin D2	Vitamin D3
Also Called	Ergocalciferol	Cholecalciferol
Source	Plants & fungi (like mushrooms)	Animal-based foods & sunlight
Strength	Less effective	More effective
Potency	Less bioavailable	More bioavailable (the body absorbs it better)
Common in Supplements?	Sometimes	Most common

Quick Tip:

If you’re buying a supplement and it says, “Vitamin D,” check the label for “cholecalciferol” — that means it’s Vitamin D3, the more effective form.

Also Read: The Fat-Soluble Vitamins: Vitamins A, D, E, & K

So… Is Vitamin D and D3 the Same?

Short answer? No.
Long answer? D3 is a type of Vitamin D.

The confusion mainly stems from labeling and marketing. Many supplements are labeled simply as “Vitamin D,” even when they contain D3. People assume they’re taking generic vitamin D, not knowing they’re actually consuming D3.

This distinction matters because:

Vitamin D3 raises blood levels of vitamin D more effectively than D2.
It stays active in your system longer.
Research shows D3 may better support calcium absorption and bone health.

Also Read: Unveiling the Powerful Connection of Geranylgeraniol and Bone Health

What Happens After You Take Vitamin D or D3?

Once you take either D2 or D3 (through food, sun, or supplements), your liver converts it to calcidiol—the form that’s measured in blood tests. Then, your kidneys turn it into calcitriol, the active form that your body uses.

This happens with both D2 and D3—but again, D3 tends to work more smoothly and effectively.

Did You Know?
The vitamin D blood test you get—called 25(OH)D—doesn’t tell you which type (D2 or D3) is in your system. It just shows your total D levels.

Also Read: What Are Lipid-Soluble Vitamins and Why Do You Need Them?

When are they Commonly Prescribed?

Most doctors recommend Vitamin D3 (cholecalciferol) for the following:

General deficiency

Bone health support

Post-menopause or elderly care

Muscle weakness

Fatigue due to low D levels

Sometimes, D2 is prescribed in high-dose medical situations, but that's usually temporary and under supervision.

Smart Buy Tip:

D3 is not just more effective — it’s also less likely to need frequent dosing.

Food Sources – D vs D3

Here’s where each type shows up naturally:

Source	Contains	Type
Fortified milk & cereals	D2 or D3 (check label)	Varies
Mushrooms (sun-dried)	D2	Plant-based
Fatty fish (salmon, mackerel)	D3	Animal-based
Egg yolks	D3	Animal-based
Liver	D3	Animal-based
Sun exposure (UVB rays)	Stimulates skin to make D3	Natural

Fun Fact:

Your skin makes Vitamin D3 naturally when exposed to sunlight. D2? You don’t make it at all — it’s only from plant sources or fortified foods.

Also Read: The Best & Worst Foods for Hormonal Balance: What to Eat & Avoid

Vegetarian or Vegan? What Are Your Options?

Most vitamin D3 supplements are derived from lanolin (a substance from sheep's wool), making them unsuitable for strict vegans. But there’s good news:

Plant-based D3 supplements made from lichen are now widely available.

Vitamin D2 remains an alternative for those who prefer not to consume any animal-derived products—though it’s less effective.

Also Read: 11 Dairy-Free Protein Shakes: Nutritionist-Approved Recipes

So, Why Even Use D2?

Fair question. D2 still exists because:

It’s cheaper to produce (especially in prescriptions)
It's used in fortified foods
Some prescription D2 doses are very high (like 50,000 IU) for short-term medical correction.

But again, in day-to-day supplements, D3 is usually the preferred choice for long-term use.

Myth Buster:

“If I spend time in the sun, I don’t need Vitamin D supplements.”

While sunlight does trigger Vitamin D3 production, age, sunscreen, location, and skin tone can all affect how much your body actually makes. In northern countries like Canada, winter sun often isn’t strong enough for sufficient D production.

Also Read: 10 Highly Inflammatory Foods to Avoid & 10 Anti-Inflammatory Foods to Include in Your Diet

How to Know If You’re Low on D?

Low vitamin D can show up as:

Tiredness
Low immunity
Body aches or joint pain

Mood swings

Weak bones or hair loss

A 25-hydroxy vitamin D blood test can confirm your levels.

Levels That Matter:

Ideal level: 30–50 ng/mL

Below 20 = deficient

Below 10 = severely deficient

Who Might Need Extra Vitamin D3?

Some people need a little extra help getting enough D3—are you one of them?

Older adults (your skin produces less with age)

People living in northern climates

Those with darker skin tones

People who spend most time indoors

Vegans and vegetarians (less access to animal-based D3 sources)

Fun Fact:

Mushrooms are the only natural plant-based source of vitamin D—but only if they’re exposed to UV light. A portobello sunbath, anyone?

What’s the Bottom Line?

Understanding the difference between vitamin D vs vitamin D3 can help you make smarter choices for your health. While both forms technically “count” as Vitamin D, D3 is often the better option for maintaining healthy levels—especially if you’re not getting much sun or eating enough D-rich foods.

Want to make the most of your supplement routine? Look for high-quality Vitamin D3, and don’t forget to keep your magnesium levels in check, too.

Also Read: Chelated Magnesium Demystified: A Guide to Absorption and Health Benefits

Key Takeaways

In the vitamin D vs vitamin D3 comparison, D3 is the most effective and commonly recommended form.
Vitamin D2 is plant-based but less potent and less bioavailable.
D3 is preferred for better absorption and longer-lasting effects.
Check your supplement label for cholecalciferol—that’s D3.
If you're unsure about your vitamin D status, ask your doctor for a simple blood test.

Disclaimer: This blog is for informational purposes only and does not provide medical advice. Always consult a healthcare professional before making changes to your diet or health routine. Individual results may vary.

References

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2. Lehmann U, Hirche F, Stangl GI, Hinz K, Westphal S, Dierkes J. Bioavailability of vitamin D(2) and D(3) in healthy volunteers, a randomized placebo-controlled trial. The Journal of Clinical Endocrinology and Metabolism. 2013;98(11):4339-4345. doi:https://doi.org/10.1210/jc.2012-4287 (Accessed on 2 july 2025)

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5. National Institutes of Health. Vitamin D. National Institutes of Health. Published 2024. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

6. Bahrami A, Farjami Z, Ferns GA, Hanachi P, Mobarhan MG. Evaluation of the knowledge regarding vitamin D, and sunscreen use of female adolescents in Iran. BMC public health. 2021;21(1):2059. doi:https://doi.org/10.1186/s12889-021-12133-5

7. MedlinePlus. Vitamin D Deficiency. Medlineplus.gov. Published 2019. https://medlineplus.gov/vitaminddeficiency.html (Accessed on 2 july 2025)

8. Bechraki L, GHM E, CPGM L, Groenendijk I. The Nutritional Benefit of UV-Exposed Mushrooms for the Dutch Population: Modeling the Addition of UV-Exposed Mushrooms to the Diet. Current Developments in Nutrition. 2023;7(12):102039-102039. doi:https://doi.org/10.1016/j.cdnut.2023.102039