Skip to main content

Vitamin D is an essential nutrient and fat-soluble vitamin that helps to ensure optimal bone health, immune function and more. If you have a deficiency in it, you need supplements to maintain proper levels of vitamin D. Understanding the differences between vitamin D2 and vitamin D3 supplements can be confusing. This article will break down their similarities and differences, explaining why these distinctions matter.

In Short: Is Vitamin D2 the Same as Vitamin D3?

The term “vitamin D” is often used to refer to both vitamin D2 and vitamin D3. Both can be ingested (as supplements or in foods) to increase the overall levels of vitamin D in your blood.

Vitamin D2 is also called ergocalciferol and is often found in fortified foods like plant-based milks, orange juice and cereals. Vitamin D2 is cheaper to produce but it may not be as well-absorbed by the body as D3. Vitamin D3 is also called cholecalciferol. Vitamin D3 is made in the skin after sun exposure and it is found in animal-based foods such as salmon, sardines, beef liver and eggs. 

Both vitamin D2 and D3 serve the same function in the body however, some research suggests that vitamin D3 is more effective in raising vitamin D levels. There may be some instances in which one form of vitamin D is preferred over the other, so it is important to work closely with your doctor when determining what type of vitamin D supplement is best for you. 

What is Vitamin D?

Keeping your daily vitamin D levels high enough helps to ensure that your body can fully absorb calcium and phosphorus, two nutrients that are essential for bone health. Healthy vitamin D levels help to keep your bones healthy and strong and prevent them from breaking down over time. 

What is Vitamin D3?

Vitamin D3 is also referred to as cholecalciferol. Vitamin D3 is produced by the body when sunlight is absorbed into the skin. Vitamin D3 can also be found naturally in certain foods such as egg yolks, beef liver and fatty fish like salmon and sardines. 

After your skin absorbs sunlight, your body converts the sunlight into vitamin D3 which then transports to the liver where it is converted to 25-hydroxyvitamin D3. In the kidneys, it is then converted into calcitriol which is the active form of vitamin D that your body can use. 

What is Vitamin D2?

Vitamin D2 is also known as ergocalciferol. Vitamin D2 is naturally found in fungi like mushrooms and yeast. Most foods that are fortified with vitamin D, such as cereal, orange juice and plant-based milk contain vitamin D2. Dietary supplements that contain vitamin D2 as the main ingredients sometimes cost less than those with vitamin D3, since this form of vitamin D can be cheaper to source. 

When you ingest vitamin D2, it is absorbed by your small intestine and transported to the liver which converts it to 25-hydroxyvitamin D2. It then moves to the kidneys where it is converted into the active form of vitamin D, calcitriol. 

Vitamin D Deficiency and Its Implications

Vitamin D deficiency, or vitamin D insufficiency, is incredibly common. Many adults will be told by their doctor that they need to supplement vitamin D in order to get their levels high enough. Vitamin D deficiency can happen to anyone but it is especially common in people who either do not spend enough time outside (getting exposure to sunlight) or who have darker skin which produces less vitamin D from sunlight exposure. You may be at an increased risk of developing vitamin D deficiency if:

  • You do not consume a lot of vitamin D-containing foods
  • You have a disease that makes it harder for your gut to absorb vitamin D (such as Celiac disease or Crohn’s disease)
  • You have a kidney or liver disease
  • You are obese 
  • You take certain medications (such as blood pressure medications, calcium channel blockers or glucocorticoids) 

Many people who have vitamin D deficiency are unaware, given that it rarely causes side effects. Symptoms from vitamin D deficiency often develop when the deficiency is very severe or it has gone on for quite some time. If you do develop symptoms from vitamin D deficiency, it may look like:

  • Fatigue
  • Depression
  • Bone and muscle pain

Vitamin D3 supplements are often prescribed to help treat a vitamin D deficiency. Although vitamin D deficiency is incredibly common, it is often easy to treat with supplementation and dietary adjustments. 

The Role of Vitamin D3 in Addressing Deficiency

Vitamin D3 is effective in treating vitamin D deficiency. Your doctor may prescribe a specific strength to help in treating a deficiency, so it is important to work closely with them, rather than just purchasing a supplement over the counter. 

Choosing Between Vitamin D2 and D3: Which is Better?

Both vitamin D2 and vitamin D3 supplements will raise your vitamin D levels to prevent or treat a deficiency. When considering whether you should take vitamin D2 or D3, there are several factors to think about. 

Studies have found that vitamin D3 is more effective at raising vitamin D levels, so your doctor may recommend D3 as a method to treat vitamin D deficiency. Some people will prefer to take vitamin D2 since it is sourced from plants while vitamin D3 is sourced from animals.

If you find out that you have vitamin D deficiency, your doctor will prescribe the best vitamin D supplement for you. Discuss with your provider whether they think that vitamin D2 or D3 is a better option for you. 

How to Best Incorporate Vitamin D2 and D3 into Your Diet

Incorporate more vitamin D-containing foods into your daily diet to maintain adequate vitamin D levels and healthy bones. Some foods with a natural source of vitamin D include:

  • Egg yolks
  • Liver
  • Trout (and other naturally fatty and oily fish)
  • Sardines
  • Milk
  • Mushrooms

Conclusion: The Key Takeaways

Keeping your vitamin D levels up is important for your overall health and wellness. If you find out that you have a deficiency, your doctor may recommend that you take one of the forms of vitamin D as a supplement. Both vitamin D2 and vitamin D3 supplements will raise your overall vitamin D levels but some research suggests that D3 is more effective. The doctors at UCF Health can help you navigate a vitamin D deficiency, recommending the best treatment regimen for your unique situation.