Can sunlight alone meet your vitamin D requirement? Study explains

Despite regular sun exposure, you may still lack enough vitamin D. Here's what experts suggest to meet your body's needs

Sun exposure alone may not be enough to maintain healthy vitamin D levels throughout the year, according to recent research. The study highlighted that even with regular sunlight; many people may not reach or sustain the recommended vitamin D levels, especially those with higher body fat or limited sun exposure.

 

The study titled vitamin D—is the sun enough for us?, published recently in Nutrition & Metabolism (2025), emphasised the need for vitamin D supplementation to support long-term health.

How much sunshine needed for vit D?

To achieve sun exposure, most experts recommend spending 5 to 30 minutes in the sun, several times a week, between 10.30 am and 4 pm. However, the study showed that this may not be enough, depending on your skin tone, location, and the time of year.

Can your body store vit D from summer for the whole year?

The study mentioned that the vitamin D made from summer sun exposure doesn’t last all year. While your body stores vitamin D in fat and muscle, this reserve may deplete faster than you think.  Researchers found that even with regular summer sun, your levels can drop significantly by winter.

How skin colour tone, and fat affect vitamin D absorption

People with darker skin need more sun exposure to make the same amount of vitamin D as those with lighter skin. The melanin in darker skin acts like a natural sunscreen, slowing vitamin D production.

 

Additionally, obesity can trap vitamin D in body fat, making it less available to your bloodstream. This means people with higher body fat may need larger vitamin D doses to achieve the same blood levels as someone with a lower body fat percentage.

 

On the other hand, active muscles can release stored vitamin D more effectively, which highlights the importance of regular exercise for vitamin D metabolism.

Can your sunscreen lotion block your vitamin D?

Many people worry that wearing sunscreen might block vitamin D production. Studies suggest that while sunscreen can reduce vitamin D synthesis, about 15 per cent of UV rays still penetrate the skin, allowing some vitamin D production. Dermatologists still recommend wearing sunscreen to protect against skin cancer and suggest getting vitamin D from food and supplements instead.

What are the best sources of vit D besides the sun?

vitamin D can also be found in:

• Fatty fish like salmon, tuna, and mackerel
• Fortified foods like milk, orange juice, and plant-based alternatives
• Egg yolks and mushrooms
• vitamin D supplements

Supplements are often the easiest and safest way to meet your vitamin D needs, especially during winter.

Should you take vitamin D2 or D3?

The study found that vitamin D3 is more effective than vitamin D2. D3 stays in your body longer and raises blood levels more efficiently. D2, on the other hand, breaks down faster and is less effective in maintaining optimal vitamin D levels over time.

How can you check your vit D levels?

The best way to measure your vitamin D status is through a simple blood test measuring serum 25(OH)D levels. Most experts recommend aiming for levels above 30 nanograms per millilitre of 25-hydroxyvitamin D (30 ng/mL) for optimal health.

 

If your levels are low, your doctor may recommend vitamin D supplements, usually in the range of 600 to 2,000 IU (International Units) per day, or more if you have obesity or severe deficiency. 

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This content is for informational purposes only and is not a substitute for professional medical advice.