Vitamin D2 vs Vitamin D3: Key Differences and Signs of Deficiency

Vitamin D2 vs Vitamin D3: Key Differences and Signs of Deficiency

Nicknamed the sunshine vitamin, vitamin D is a complex nutrient that affects not only our bones but nearly every part of the body. In recent years just how essential vitamin D is to our functioning has come to light. There’s much debate over whether it makes a difference in the type of vitamin D you take in, vitamin D2 or vitamin D3. But first, a little about why it is so important to our physical health. 

Vitamin D Deficiency: A Global Problem

In the early 1900s, soft bone development in young children was a widespread health crisis in Northern Europe and certain areas of the Northern United States. 

By the 1930s, researchers found that children who took cod liver oil regularly or spent most of their time outside were less likely to suffer from impaired bone development. In response, vitamin D began to be added to foods like cereal and milk to help ensure children and adults received this all important nutrient. 

Even with fortified foods, it’s estimated that nearly 1 billion people are deficient in vitamin D worldwide and about one-third of Americans are low on vitamin D. How can so many people have low vitamin D levels when all it takes is a little time outside to boost your vitamin D? 

Lifestyle and culture plays a key role. Fortified foods like milk, juice and cereal are not staples within the majority of Americans diets anymore. It is also important to note that with the increasing role of technology in every aspect of life, children spend less time playing outdoors and more time inside on their device of choice. 

The modern workforce typically spends the day indoors, shielded from the sun’s UV rays and its vitamin D enhancing effects. Also, pollution can obscure sun rays just as much as a cloudy day. Clothing that covers the majority of the skin will also reduce how much sunlight is absorbed by the epidermis.

Risk Factors for Vitamin D Deficiency

Intestinal Health:

The GI tract is essential for removing nutrients from the food we eat and making it available to the body. Compromised intestinal health could mean less vitamins are being absorbed by your body.*

Lack of Sun: If you work indoors or wear clothing that exposes very little skin your body will receive less sunlight and less opportunity to synthesize vitamin D.

Vegan Diet: Other than mushrooms, there are not many plant based sources of high vitamin D.

Skin’s Melanin Content: The higher the melanin content in skin, the less sunlight is absorbed. Studies show that those with lighter skin color tend to have higher levels of vitamin D than those with darker skin tone. Studies show that on average darker skin tones have lower serum levels of vitamin D.

Vitamin D2 and Vitamin D3

There are several forms of vitamin D, but the two main forms found in food are vitamin D2 and vitamin D3. Vitamin D2, ergocalciferol, is most often found in plants. A serving of mushrooms contains nearly 15% of the amount of the daily adult requirement of vitamin D mainly in the form of D2. 

Mushrooms and yeast respond to sunlight by creating vitamin D, much in the same way that we do. The more sunlight rays that hit the plant’s surface, the higher the vitamin D content.

Vitamin D3, cholecalciferol, is most abundantly found in animal products like butter, milk, eggs and certain types of meat like salmon, tuna and beef liver. It’s a myth that D2 is only in plants and D3 is only in animal products, it’s just that those are the sources in which you will find the highest amounts of those particular forms of vitamin D. 


For instance, vitamin D3 has surprisingly been found in some species of algae. Ergocalciferol and cholecalciferol are technically precursors that our body converts to its preferred bioavailable form of vitamin D, calcitrol. 

Vitamin D2 vs. Vitamin D3 Debate

Vitamin D3 is formed when sunlight reaches our skin and is then converted into calcitrol. There is some evidence that suggests this form of vitamin D is more bioactive and in turn, more effective in increasing our concentration of vitamin D stores than D2. In one study two groups of individuals received 50,000 IU of either vitamin D2 or vitamin D3 two times a week, for 5 weeks. Although both groups received the same dosage amount, the vitamin D3 group had higher measurable levels of vitamin D in their body in comparison to the vitamin D2 group. While both forms of vitamin D will do the job, vitamin D3 is a potent and more bioavailable option for those looking to supplement their diet.*

Vitamin D Deficiency’s Domino Effect

Since vitamin D isn’t just a nutrient but a hormone, if you aren’t getting enough it can affect everything from your mood to sore muscles.* Practically everyone knows how a severe deficiency of vitamin D can lead to serious problems with bone development.* 

The bones are made up of calcium, but the mineral calcium can’t be absorbed without a little help from its friend, vitamin D. A deficiency in vitamin D can result in only 10-15% of the calcium you take in being absorbed.*

Besides bone development, the body needs calcium for other processes. If it doesn’t have what it needs to do its job, our ever-resourceful bodies will get calcium from the next best source– leeching it directly from the bones.* 

As you can imagine, over time this can lead to brittle or softened bones and other serious health problems.* Vitamin D is also needed to properly absorb phosphorus, so if you are low, you can experience a severed drop in this nutrient, absorbing only around 60% of what you ingest.* 

Health Problems Related to Low Vitamin D

  • Fragile Bones: Low vitamin D may increase the risk of developing soft, brittle and porous bones.*
  • Muscle Weakness: Increased pain in the muscles and joints can occur with low vitamin D.* Studies show that low vitamin D levels are related to an increased risk of falls in the elderly population. 
  • Low Mood: Early research shows that vitamin D plays a role in the release of serotonin, a mood regulating hormone within the brain.
  • Increased Infections: Low vitamin D levels have been connected with an increased rate of upper respiratory tract infections in several studies. 

Signs of Vitamin D Deficiency

  • Muscle pain*
  • Fatigue*
  • Low or depressed mood*

    How to Increase Vitamin D

    • Make sure you are getting your magnesium. Magnesium plays a role in the enzymes used by the body to process Vitamin D, so if you are low on magnesium it may cause a domino effect and lower your serum levels of vitamin D.*

    • Vitamin D is fat soluble, so it is best absorbed with a meal that contains some fat.

    • Take a supplement with Vitamin D3. This form of vitamin D is more efficient in increasing vitamin D stores.*

    • Eat vitamin D rich foods like mushrooms, cottage cheese and fortified milk.

      It’s amazing to think that this nutrient and hormone can be created within our bodies just by spending a few leisurely moments in the sun. Of course, sun exposure comes with its own risks, so it is advisable to find other ways to get your vitamin D intake. If you are looking for a quality supplement for your vitamin D needs, Nature’s Lab offers quality formulas that can support your health goals.

      This article is for informational purposes only. It is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and should never be relied upon for specific medical advice. To the extent that this article features the advice of physicians or medical practitioners, the views expressed are the views of the cited expert and do not necessarily represent the views of Nature's Lab or its affiliated brands.


      Vitamin D. Linus Pauling Institute. (2022, January 3). Retrieved January 19, 2022, from

      Aranow, C. (2011, August). Vitamin D and the immune system. Journal of investigative medicine : the official publication of the American Federation for Clinical Research. Retrieved January 19, 2022, from 

      Ames, B., & Patrick, R. (2015, June 29). Vitamin D and the omega-3 fatty acids control serotonin synthesis and action, part 2: Relevance for ADHD, bipolar disorder, schizophrenia, and impulsive behavior. FASEB journal : official publication of the Federation of American Societies for Experimental Biology. Retrieved January 19, 2022, from 

      Tripkovic , L., Lambert, H., Hart, K., Smith, C., Bucca, G., Penson, S., Chope, G., Hyppönen, E., Berry, J., Vieth, R., & Lanham-New, S. (2012, May 2). Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: A systematic review and meta-analysis. The American journal of clinical nutrition. Retrieved January 19, 2022, from 

      Sizar, O. (2021, July 21). Vitamin D deficiency. StatPearls [Internet]. Retrieved January 19, 2022, from 

      Zeratsky, R.D., LD, K. (2020, August 27). What are the risks of vitamin D deficiency? Mayo Clinic. Retrieved January 19, 2022, from 

      Holick, PhD, MD, M. F. (n.d.). The vitamin D deficiency pandemic: A forgotten hormone ... Public Health Reviews. Retrieved January 19, 2022, from