Too Much or Too Little — How Much Vitamin D Do You Need?

October 28, 2025

3 min read

Around 1 billion people on the planet are vitamin D deficient. First and foremost, at risk are those living in regions where there is little sunshine. However, others may also experience this health issue. What is vitamin D deficiency, and how to get it compensated?

Key takeaways

Around 1 billion people on the planet are vitamin D deficient.
The Benefits of Vitamin D
How Much Is Enough?

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People exploring Vitamins and minerals through vitamins, healthy lifestyle.

Why it matters

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Article author

Dr. Aleh

Endocrinologist, Nutritionist

Vitamin D, also known as 25(OH)D, is much more than just a vitamin. It is, first and foremost, a calcitriol hormone. Unlike other vitamins, our body can produce vitamin D by being in sunlight. This is why it is sometimes known as the sun vitamin. We also get vitamin D from foods such as fish, liver, or eggs.

The Benefits of Vitamin D

Vitamin D has lots of benefits. It promotes the absorption of calcium in the gut and keeps bone tissue dense. Vitamin D improves skin elasticity, reproductive health, and the immune system, helping to prevent colds and chronic fatigue. When present in sufficient quantities, vitamin D decreases the risk of several types of cancer, diabetes, multiple sclerosis, cardiovascular disorders, and tuberculosis.

How Much Is Enough?

The average level of vitamin D in the human body is 30–100 ng/mL. For those who work in offices, the normal level of vitamin D could be lower, around 35–40 ng/mL. People who work out regularly have an average level of 50 ng/mL. Vitamin D levels also depend on age (decreasing with age), season (low during winter and high during summer), and quality of nutrition.

During pregnancy, vitamin D concentration is lower in women’s bodies. Regardless of your lifestyle, it is recommended to take vitamin D as a preventative measure, especially if you live in an area with low sun exposure. Before taking the medicine, you should take a 25-0H vitamin D blood test to determine the amount your body needs.

The amount of vitamin D and other vitamins in your body should be monitored on an ongoing basis. Keep the results of all the tests in the Ornament app so that you always have your data at hand!

What Happens When You Don't Get Enough of It?

Since this vitamin plays an active role in calcium and phosphorus metabolism, a deficit will have an immediate effect on the appearance of nails, teeth, and hair. Bones become more prone to injuries, while bone fractures take longer to heal. A low level of vitamin D can lead to depression. Frequent infections, diseases, fatigue and muscle weakness, bone and joint pain, and slow healing of wounds can all be signs of a vitamin D deficiency.

The recommended intake of vitamin D for those who lack sun exposure is from 400 to 600 IU per day. This should help prevent a deficiency. In the case of vitamin D deficiency, the dosage should be determined by your physician. As a rule, to normalize vitamin D levels in a body suffering from a deficit, prescribed dosages vary from 800 to 1,000 IU per day. The amount can be taken in the form of supplements or other sources. You should not self-medicate. Overdoses of vitamin D are rare but can cause health damage.

Overdose

The good news is that you cannot overdose on vitamin D if it is not taken as a supplement. However, it is quite possible to overdose after prolonged intake in high quantities. Daily dosage above 2,000 IU can potentially be toxic.

The most common overdose symptoms include confusion, lack of concentration, drowsiness, depression, vomiting, abdominal pain, constipation, and high blood pressure. These symptoms show up with vitamin D concentrations exceeding 140 ng/mL. To stop symptoms and recover, simply stop taking vitamin D supplements.

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