Introduction
Vitamin D is one of the most important vitamins, especially in Estonia where sunlight is scarce for much of the year. EFSA has confirmed that vitamin D contributes to the normal function of the immune system, and the maintenance of normal bones, teeth, and muscle function. But at the supplement shelf, you face a choice: D2 or D3?
In this article, we explain the differences between these two forms and help you make the best choice.
What is vitamin D2?
Vitamin D2, or ergocalciferol, is the plant-derived form of vitamin D. It is produced from mushrooms and yeast exposed to ultraviolet radiation. D2 has historically been used in prescription medications and food fortification.
Vitamin D2 is always suitable for vegetarians and vegans, since its source is fungi, not animal-derived.
What is vitamin D3?
Vitamin D3, or cholecalciferol, is the form of vitamin D that human skin produces when exposed to sunlight. In supplements, D3 is typically derived from lanolin (fat extracted from sheep's wool) or from lichen, which is a vegan-friendly alternative.
D3 is chemically identical to the form your body produces naturally (Holick, 2007).
Key differences
| Feature | Vitamin D2 | Vitamin D3 |
|---|---|---|
| Chemical name | Ergocalciferol | Cholecalciferol |
| Source | Mushrooms, yeast | Lanolin, lichen, fish oil |
| Vegan option | Always vegan | Vegan only if lichen-derived |
| Effect on blood vitamin D levels | Moderate | Generally more effective |
| Stability | Less stable | More stable |
| Price | Typically similar | Typically similar |
| Availability | Less common | Very common |
When to choose vitamin D2
- You are a strict vegan and want a guaranteed plant-based form — D2 is always plant-derived
- D2 has been prescribed by your doctor — in some countries, high-dose D2 is dispensed by prescription
- You already consume D2-fortified foods and want to continue with the same form
When to choose vitamin D3
- You want the most effective form — research shows D3 raises and maintains blood 25(OH)D levels better than D2 (Tripkovic et al., 2012)
- You are looking for a more stable supplement — D3 is more stable during storage
- You are vegan and can find lichen-derived D3 — this combines vegan-friendliness with D3 efficacy
- You live in Estonia or another northern country where vitamin D deficiency is common — D3 is the best choice for achieving optimal levels
Can you combine them?
Theoretically yes, but in practice it is unnecessary. Choose one form and use it consistently. If you are already taking D3, adding D2 provides no benefit. Monitor your total intake — EFSA has set the tolerable upper intake level for vitamin D at 100 µg (4000 IU) per day for adults.
Frequently asked questions
Is D3 really better than D2?
Yes, most studies show that D3 raises blood 25(OH)D levels more effectively and maintains them at higher levels for longer. It is also the form your body produces naturally.
Can vegans take vitamin D3?
Yes, lichen-derived D3 is fully vegan. Look for the vegan label on the product.
How much vitamin D should I take in Estonia?
Estonian nutrition guidelines recommend 15–20 µg (600–800 IU) per day for adults. During the dark season, needs may be higher. Consult your doctor.
Can you overdose on vitamin D?
Yes, vitamin D is fat-soluble and excess can accumulate in the body. Follow recommended doses and consult your doctor if needed.
Should vitamin D be taken with fatty food?
Yes, vitamin D is fat-soluble and absorbs better when taken with a meal containing some fat.
References
1. Tripkovic L, Lambert H, Hart K, et al. (2012). Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis. American Journal of Clinical Nutrition, 95(6), 1357-1364.
2. Heaney RP, Recker RR, Grote J, et al. (2011). Vitamin D3 is more potent than vitamin D2 in humans. Journal of Clinical Endocrinology & Metabolism, 96(3), E447-E452.
3. Holick MF. (2007). Vitamin D deficiency. New England Journal of Medicine, 357(3), 266-281.
4. Armas LA, Hollis BW, Heaney RP. (2004). Vitamin D2 is much less effective than vitamin D3 in humans. Journal of Clinical Endocrinology & Metabolism, 89(11), 5387-5391.
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See also:
- Vitamin D in Estonia: Why It Matters Especially Here
- Best Vitamin D Supplements
- Vitamin D and the Estonian Climate
Disclaimer
A food supplement is not a substitute for a varied and balanced diet and a healthy lifestyle.
