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How Is Vitamin D Made

How is Vitamin D Made? (The Magic Power of Your Skin)

by The Nutrivy Crew, April 14th 2021

Reading Time: 7 minutes

Have you ever wondered about how is Vitamin D made by your skin?

Like what goes on behind the scenes and the chemical reactions?

It’s such a beautiful, natural process that’s handled by your body when you’re exposed to sunshine.

But what’s the best time to stay in the sun, for how long and what about in the winter when there’s no sun? What if you get sunburnt?

If you’re looking for answers to these questions, you’re in the right place.

I’ve done the research and spoken to the experts to bring you answers to all these questions.

I’ll also tell you about how they make Vitamin D supplements and when’s the best time to take them.

So stick around and read on.

How is Vitamin D Made In The Skin?

When Ultraviolet B (UVB) rays from the sun hit your skin it interacts with a protein called 7-Dehydrocholesterol (7-DHC).

This interaction produces a form of Vitamin D called cholecalciferol.

Cholecalciferol is then converted to calcidiol by the liver which finally produces the active chemical form of Vitamin D in the kidneys (called calcitriol).

The Science (Going One Step Deeper)

So how exactly does this work?

If we go a bit deeper into science, natural light contains different rays and wavelengths.

Types Of UV (Ultraviolet) Rays

Although there are many types of rays produced by the sun, UV rays are the most useful and damaging to our skin.

The UV rays wavelengths from the sun operate in the range (100–400 nm) and are divided into 3 brands:

  • UVA (315 to 400 nm)
  • UVB (280 to 315 nm)
  • UVC (100 to 280 nm)

Short wavelength UVC is the most dangerous type of radiation but thankfully it’s completely filtered out by the earth’s ozone layer.

Long-wavelength UVA accounts for around 90% of the UV radiation reaching the earth’s surface and causes skin ageing and wrinkles.

Medium wavelength UVB is biologically active and help produce Vitamin D3 in your skin.

Both UVA and UVB have a high amount of energy and long term exposure to either could damage your skin.

So if you’re wondering do you get Vitamin D from tanning beds, the answer is No.

Tanning beds use mostly UV-A rays and can damage your skin causing burns and skin cancer.

Vitamin D2 vs D3

There are 2 forms of Vitamin D — D2 (ergocalciferol) and D3 (cholecalciferol).

Vitamin D2 comes from plants and made in the skin of mushrooms when exposed to sunlight.

The human body only produces Vitamin D3 and is the active and used form.

How is Vitamin D Made?

When the UVB rays strike the surface of the skin, they interact with a protein called 7-Dehydrocholesterol (7-DHC) which is a derivative of the steroid cholesterol that’s already present in your skin.

This produces a form of Vitamin D called cholecalciferol.

Cholecalciferol is then converted to Calcidiol by the liver.

The last step of the process is the conversion of Calcidiol to Calcitriol by the kidneys. This is the active form of Vitamin D which is available to use by the body.

Your body disposes of the inactive form of Vitamin D called Calcitroic Acid.

The concentrations of Vitamin D peak for 24–48 hours after exposure to the UVB rays.

This research paper published by the Faculty of Medicine, Cairo University shows how Vitamin D is made by the body.

How Is Vitamin D Made By Your Body Infographic

How Long Should You Stay In The Sun For Vitamin D?

It’s not known exactly how much time in the sun generates the most Vitamin D.

This varies by skin colour and the amount of skin exposed.

If you live far from the equator, certain times are better than others with less risk of skin cancer.

A study published by the University Of Manchester in 2010 sheds more light on it.

It showed that Caucasian adults in the UK obtained healthy levels of Vitamin D with just 13 minutes of mid-day sunshine exposure during summer, 3 times a week.

Another study done in Oslo, Norway showed similar results (30 minutes).

The majority of studies showed that between 10–30 minutes per day during summer 3 times a week produced healthy levels of Vitamin D.

Best Time To Stay Out In The Sun

So, you know that you need to spend around 30 minutes a day (3 times a week) in the sun, but what time should you go?

Some family remedies say early morning, some say afternoon due to the “golden light”.

The news and government say something entirely different.

Studies show that the midday sun is the most effective at generating Vitamin D efficiently.

This is because, at midday, the sun is at its highest point and the UVB rays are the most intense.

So you need to spend less time in the sun to get the correct amount of Vitamin D.

This also reduces the chances of skin cancer and sunburn.

A couple of studies were also done in India and Saudi Arabia to test the results of Vitamin D generation.

They found that the per cent conversion of 7-Dehydrocholesterol (7-DHC) to Vitamin D3 was largest between 11 am to 2 pm.

If you’re lucky to have some sunshine go out around midday for the most efficient Vitamin D.

Dr Karl Insogna, MD, director of Yale Medicine’s Bone Center says

Because skin cancer, particularly melanoma, can be such a devastating disease, it’s best to use sunblock when outdoors in strong sunlight for any prolonged length of time. Because this may limit the amount of vitamin D you get from sun exposure, make sure your diet includes sources of vitamin D from foods or supplements.

How To Get Vitamin D In Winter?

If you live around the equator, you’re lucky and you should get enough Vitamin D all year-round.

But what if you’re so far away that being near the equator is only possible on a vacation?

During winter, as you go further from the equator, the ozone layer absorbs UVB rays from the sun and hardly any make it through.

So you need to stay in the sun for longer to get a healthy dose and avoid a Vitamin D deficiency.

A research study was done in Andene, Norway on 60 volunteers (44 women, 16 men) had interesting results.

They collected blood samples for one year at two-month intervals and analysed them for 25 Hydroxy Vitamin D [25(OH)D].

Data on dietary intake, time spent in the sun and sunbeds were also collected.

It found that people in the Northern Hemisphere (like Norway, Canada, USA) were unable to produce their own Vitamin D during the months of October — March.

So during winter, you need to get Vitamin D from food or supplements.

In case you’re wondering can Vitamin D deficiency affect teeth, the answer is yes. I spoke with a dentist to explain exactly how tooth decay happens as a result of Vitamin D deficiency.

Skin Colour

The colour of our skin is determined by the amount of melanin we have.

Melanin is a pigment that absorbs harmful UV rays and protects you against skin cancer and sunburn.

Darker-skinned people have more melanin while lighter-skinned people have less.

As you can imagine the sun’s rays are very strong at the equator.

Hence people living around the equator are generally darker than those living away.

Research shows that darker-skinned people need to spend anywhere from 30 minutes to 3 hours extra in the sun to get the same amount of Vitamin D as a lighter-skinned person.

So if you’re on the darker side of the spectrum it’s better to spend a bit more in the sun to get your daily Vitamin D intake.

How Is Synthetic Vitamin D Made?

So that’s all about the natural stuff.

It’s beautiful how your body is able to produce and regulate its own Vitamin D production from sunshine.

Unfortunately, during winter that’s hard to do.

So the recommended way to get Vitamin D in winter is through food and supplements.

Foods like eggs, oily fish (salmon, herring, sardines), mushrooms and fortified milk and cereal are good sources of Vitamin D,

But, they contain very little of it.

If you practice a vegan lifestyle it’s even harder to find a good reliable food source of Vitamin D.

So how is Vitamin D made exactly from supplements?

Vitamin D from Lanolin (Sheep's Wool)

Use of Lanolin In Vitamin D Supplements

Vitamin D supplements are made from Lanolin, a fatty oil-like substance secreted by the skin glands of sheep to preserve their wool.

The sheep’s wool is first washed to remove any parasites, faeces or other material.

Crude lanolin is extracted from the wool through a process called centrifugation.

After a solvent wash and chromatography, the compound 7-dehydrocholesterol (7 DHC) is finally produced.

This mimics the Vitamin D generated by your skin from sunlight.

Lanolin is also used in some health and beauty creams.

Enter Lichen (A Vegan Alternative)

If you’re vegan or a strong promoter of sustainability you don’t want to use the oil from sheep’s skin.

The good news is there are now Vegan Vitamin D supplements on the market.

The company Vegetology has developed the Vitashine version of Vegan Vitamin D from Lichen.

Lichen is a result of the symbiotic association between a fungus and algae and cyanobacteria.

It’s currently the only true vegan source of Vitamin D for supplements.

When Should I Take Vitamin D Morning Or Night?

In our other article, we explored can vitamin d supplements cause insomnia?

Low Vitamin D levels affect your quality of sleep.

Studies showed high dose Vitamin D supplements affected the production of melatonin (your sleep hormone), although research is still ongoing.

There is no concrete evidence proving that Vitamin D supplements are more effective at any certain time.

Take supplements during the day at a convenient time to avoid any interference with the quality of your sleep.


I hope this article helped you understand how is Vitamin D made magically by your body and supplements.

Make sure you get at least 30 minutes of sunshine a day all over your body.

And during winter take Vitamin D supplements so you don’t fall short and start experience symptoms of a deficiency.

Join our Vitamin D Fan Club — a private Facebook group.

Here you’ll connect with fellow health lovers and learn all things Vitamin D, all things natural supplements.


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