Vitamin D2 Supplements May Not Be as Good as You Think

Topic: Health

A study found that taking vitamin D2 supplements can lower levels of vitamin D3 in the body. Researchers from the University of Surrey and other institutions reviewed 20 studies and found that people who took vitamin D2 had significantly lower concentrations of vitamin D3 compared to those who didn't take it. This effect was seen even though vitamin D2 itself raises overall vitamin D status.

Vitamin D is an essential nutrient for our bodies. It helps us absorb calcium, which is crucial for healthy bones. Vitamin D also plays a role in muscle, nerve, and immune function.

In the UK, people are advised to take 10 micrograms (µg) of vitamin D each day during the darker months when sunlight is weak. There are two main forms of vitamin D: vitamin D2 and vitamin D3. Vitamin D2 is produced from fungi or yeast exposed to ultraviolet light, while vitamin D3 is made in human skin after exposure to UVB radiation from sunlight.

A study published in 2025 found that taking vitamin D2 supplements can lower levels of vitamin D3 in the body. Researchers reviewed 20 studies and found that people who took vitamin D2 had significantly lower concentrations of vitamin D3 compared to those who didn't take it. This effect was seen even though vitamin D2 itself raises overall vitamin D status.

The study suggests that taking vitamin D3 supplements may be more beneficial for most individuals than taking vitamin D2. However, scientists do not yet have a definitive explanation for why this happens. One possibility is that the body's mechanisms for regulating vitamin D cause it to break down and remove excess compounds when concentrations rise.

Why It Matters

This study matters because many people in India take vitamin D supplements during the winter months when sunlight is weak. If taking vitamin D2 supplements can lower levels of vitamin D3, it could have implications for public health policies and recommendations.

Key Facts

• A study published in 2025 found that taking vitamin D2 supplements can lower levels of vitamin D3 in the body.
• Vitamin D2 is produced from fungi or yeast exposed to ultraviolet light, while vitamin D3 is made in human skin after exposure to UVB radiation from sunlight.
• The study suggests that taking vitamin D3 supplements may be more beneficial for most individuals than taking vitamin D2.
• 10 micrograms (µg) of vitamin D each day is the recommended amount during the darker months in the UK.
• Scientists do not yet have a definitive explanation for why taking vitamin D2 supplements can lower levels of vitamin D3.

Key Terms

Vitamin D2

A form of vitamin D produced from fungi or yeast exposed to ultraviolet light.

Vitamin D3

The same form of vitamin D made in human skin after exposure to UVB radiation from sunlight.

Implications

This study matters because many people in India take vitamin D supplements during the winter months when sunlight is weak. If taking vitamin D2 supplements can lower levels of vitamin D3, it could have implications for public health policies and recommendations.