Vitamins D2 vs D3: What’s the Difference?

Published July 31st, 2020 by Bridget Reed
Fact Checked by
Chris Riley

If you think it’s easy to make sure you’re getting enough vitamin D, think again. According to a 2011 study by the National Health and Nutrition Examination Survey, approximately 42 percent of American adults are vitamin D-deficient. The problem is more pronounced in minority groups, with Black people reporting vitamin d-deficiency rates of 82 percent and Hispanic populations reporting vitamin d-deficiency rates of 70 percent. People located far north or far south of the equator are more likely to have vitamin D deficiencies, as well due to not getting enough sun exposure to absorb the sunshine vitamin. 

While many people assume that all you need to do to get enough vitamin D is spend time outdoors in the sun each day and drink some milk with dinner, the reality is more complicated. Vitamin D is an essential vitamin that helps many different processes in the body to function properly, including calcium absorption for bone health. 

What many people don’t realize is that the vitamin we refer to as vitamin D is actually a family of vitamins that comes in two main forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). When comparing the two forms of vitamin D, vitamin D2 vs vitamin D3, it’s important to find out which one to take and how to get the dose you need. 

What is vitamin D?

Vitamin D is a fat-soluble vitamin that aids in the absorption of calcium, helps to promote and regulate bone growth, and supports the immune system. Our bodies naturally produce vitamin D with sun exposure, and the rest of our vitamin D needs are ideally met through dietary sources. However, vitamin D is found naturally in very few foods. Vitamin D naturally occurs in foods like beef liver, cheese, egg yolks, and oily fish like salmon, tuna, and mackerel. Otherwise, it is most often found in foods fortified with vitamin D, including soy milk, orange juice, some cereals, and some dairy products.   

Why do we need vitamin D?

Vitamin D is most commonly known for its importance in supporting bone growth and bone health because it helps the body with calcium absorption, strengthening the bones. In addition to helping our bodies build and maintain strong bones, vitamin D also plays numerous other roles in our health, including: 

  • Supporting the immune system and fighting disease
  • Regulating mood and reducing depression
  • Supporting weight loss
  • Supporting healthy skin

How do you know if you need more vitamin D?

Most people assume that they get enough vitamin D from sun exposure and dietary sources, but the evidence says otherwise. If you don’t eat many foods that contain vitamin D or don’t spend much time in the sun, you’re at an increased risk of vitamin D deficiency. Additionally, there are several symptoms associated with vitamin D deficiency:

  • Feelings of fatigue, aches, and pains, or an overall sense of not feeling well
  • Significant pain or weakness in the muscles or bones that makes performing normal activities, such as going up and down stairs or getting up from the floor or a low chair, too difficult
  • Walking with a waddling gait due to pain in the bones or muscles
  • Stress fractures, especially when experienced in the hips, pelvis, or legs

Finding out whether or not you have a vitamin D deficiency can be determined by a simple blood test ordered by your healthcare provider. 

Don't miss out on savings!

Get the best ways to save on your prescriptions delivered to your inbox.

Blog Newsletter Form
By signing up, I agree to USA Rx's terms of service and privacy policy.

What is the difference between vitamin D2 and vitamin D3?

There are several differences between vitamin D2 and vitamin D3. First, the sources of the vitamins are different; vitamin D2 is found in plant sources, including mushrooms, while vitamin D3 is only found in animal products such as oily fish, egg yolks, and butter. 

The type of vitamin D produced by our bodies in response to sun exposure is Vitamin D3, while vitamin D2 is not produced by the body. Instead, vitamin D2 is produced by plants and mushrooms when they are exposed to sunlight. Because vitamin D2 is produced by plants, it is less expensive to produce and therefore makes up the majority of vitamin D that is used to fortify foods like dairy products and cereals. 

Studies show that vitamin D3 is more effective at raising the levels of calcifediol, the main circulating form of vitamin D in the bloodstream; blood levels of calcifediol are measured in order to determine whether or not a person is deficient in vitamin D. Vitamin D2 supplements also require a prescription when purchased in large quantities, while vitamin D3 supplements do not. The two vitamins also have different therapeutic applications.

What conditions are treated with vitamin D2?

Vitamin D2 supplements are predominantly prescribed for the treatment of certain medical conditions, including:

  • Hypoparathyroidism, or reduced functioning of the parathyroid glands
  • Hypophosphatemia, or low levels of phosphate in the blood
  • Rickets, a softening of the bones that occurs as a result of vitamin D deficiency

While vitamin D2 is generally prescribed for the treatment of these and other medical conditions, vitamin D3 supplements are most often recommended as a dietary supplement to raise the overall levels of vitamin D in the body. Vitamins D3 supplements are generally available over the counter in the vitamin supplement section of your local pharmacy, and is often also present in multivitamins. 

How much vitamin D do you need each day?

The United States Institute of Medicine recommends that adults take in 400-800 ICU, or 10-20 micrograms, of vitamin D per day; this level is said to be adequate for 97.5 percent of individuals. However, this daily recommended intake may need to be adjusted for people who do not receive regular exposure to the sun or who have osteoporosis, as they are not adequate to boost vitamin D levels in patients who are already deficient. Therefore, a daily dose of 1000-4000 ICU, or 25 - 100 micrograms, is recommended in order to ensure that sufficient levels of vitamin D are reached in most people. 

A few last notes: while most people in the modern day end up benefiting from vitamin D supplements, you should always consider seeking medical advice before beginning vitamin D supplementation or adding any other vitamin supplements into your daily routine. Additionally, while sun exposure is a great way to increase vitamin D levels, remember to always wear sunscreen to help protect against UVB and skin cancer. 



Instant Offer from a USA Rx Partner

Put drug prices & coupons in your pocket!

We'll text you a link to download our free Android or iPhone app