What Is The Difference Between Vitamin D2 and D3?

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Vitamin D consists of more than one type of vitamin. When it comes to your diet and supplements, there are two common types of nutrients, vitamin D2 and vitamin D3, that can help you to reach your daily vitamin D requirement. 

This article explains the difference between vitamin D2 and D3 and what the benefits of each are. 

Related: Vitamin D for Different Skin Types 

What is vitamin D?

Vitamin D is an incredibly important vitamin that will help to absorb calcium, helps to regulate bone growth, and plays a vital role in your immune system function.

You produce vitamin D when your skin is exposed to sunlight. This can become problematic for those who spend a lot of time indoors or live at high altitudes. People who fall into this category will need to get more vitamin D through their diet or through supplements. 

Some of the best foods that contain vitamin D are fatty fish, fish oil, egg yolks, butter and liver. 

For some, it can be challenging to get the proper amounts of this vitamin through diet alone, as these natural sources can be rare for some, and means that they may struggle to get enough.

Luckily, some food manufacturers add vitamin D to their products, especially with foods such as milk, margarine, and cereals. Always check the label if you want to know if these products contain additional vitamin D. Supplements are also another great way of getting extra vitamins into your system if you’re struggling with vitamin D deficiency. 

Vitamin D comes in two primary forms:

  • Vitamin D2 (ergocalciferol)
  • Vitamin D3 (cholecalciferal)

We’ll discuss the differences between the two below.

Vitamin D3 comes from animals, and vitamin D2 comes from plants. The types of vitamin D can differ depending on their food sources. 

Vitamin D3 only comes from animals such as fish, liver, and egg yolks. Vitamin D2 mainly comes from plants.

An overview of sources of vitamin D3:

  • Fish liver oil
  • Fatty fish
  • Egg yolks
  • Butter and margarine
  • Dietary supplements

An overview of sources of vitamin D2:

  • Some mushrooms (not all of them will contain D2)
  • Dietary supplements

Related: Vitamin D for different skin types and ages

Vitamin D3 is formed in your skin 

Vitamin D3 will be produced when your skin is exposed to sunlight. 

Ultraviolet (UVB) radiation aids the formulation of Vitamin D3 to form the compound 7-dehydrocholesterol in the skin (1).

A similar process happens in plants and mushrooms. The UVB light formulates D2 from ergosterol, which is the compound found in plant oils (2).

It is vital that you don’t spend an extended period of time in the sun without wearing sunscreen. This is more so important for those who have lighter skin tones. Sunburn has been proved to be a significant factor in skin cancer diagnosis (3).

Like dietary Vitamin D, it’s not possible to produce too much vitamin D in your skin. If you have enough of this vitamin in your body, your skin will just produce less.

For those who get very little sun from being indoors, who wear full-body coverings, and live in places that don’t get too much sun during winter, you must regularly eat rich vitamin D foods to make up for the lack of sunlight.

Vitamin D3 is more effective at improving your overall vitamin D levels 

Both vitamin D2 and D3 each have their own benefits, but they are not totally equal when it comes to increasing the overall vitamin D levels in your blood.

Both vitamins are absorbed into your bloodstream, but the liver metabolises them in different ways. Vitamin D3 is better than D2 at improving the overall vitamin D status. Read our ‘Vitamin D3: Usage, Health Benefits & Side Effects‘ guide for more information.

Vitamin D2 supplements might be lower quality

Research suggests that vitamin D2 supplements may be of lower quality than the D3 supplements. Vitamin D2 is said to be more sensitive to humidity and temperature. Vitamin D2 is likely to degrade over time (4). Scientists still need to carry out more studies to prove how relevant this is to human health.

Until more up to date research proves others, there’s no need to worry about the quality of your vitamin D2 supplements. You should store this form of supplement at room temperature and out of direct sunlight.

How to improve your vitamin D levels 

There are multiple different ways of improving your vitamin D levels. Here are a few suggestions:

  • Eat mushrooms that have been grown in UV light (5)
  • Take fish oil supplements
  • Try and eat fatty fish twice a day (6)
  • Choose milk that contains additional vitamin D
  • Eat egg yolks and butter (in moderation)
  • Try and spend at least 30 mins in the sun daily. Make sure you wear sunscreen to protect yourself. 

If you plan on taking vitamin D supplements, it is recommended that you do not exceed the suggested daily intake, which is 4,000 international units per day for adults (7).

The US Institute of Medicine states that the recommended daily allowance is 400-800 per day, and the common supplemental dosage ranges from 1,000-2,000 IU per day. 

For more information on how much vitamin D to take based on your age and skin type, read our guide on ‘Vitamin D for Different Skin Types.

The bottom line

The most common types of vitamin D sources are vitamin D2 and D3. 

Vitamin D3 is found in animal-sources foods such as fatty fish and egg yolks, but your skin also produces it when exposed to natural sunlight or UV lights. Vitamin D is found in plant-based sources such as mushrooms. 

The vitamin D3 is thought to be more effective at raising your system’s overall vitamin D levels. Scientists are awaiting on the latest research to see how this directly relates to human health. 

In order to maintain the right level of vitamin D, it’s essential to eat plants of foods rich in Vitamin D. Where possible, spend 30 minutes a day in the sun, but make sure you wear sunscreen to protect yourself from burning. 

 If you’re thinking about taking supplements, vitamin D3 is likely to be the most effective choice.