Fuel your life with the purest vitamins
Nov 3rd 2025
Vitamin D2 versus Vitamin D3
. . . What's the difference?
If you get the 25(OH)D test for vitamin D status that we urge everyone to get, you’re likely to find you’re deficient. It’s also likely your doctor will offer you a prescription for Drisdol, a synthetic form of vitamin D. Thank your doctor, but call us rather than fill that prescription. Drisdol is vitamin D2, a form of vitamin D that is less effective than vitamin D3 (the form of vitamin D we carry) and may even be harmful.
There are two basic forms of vitamin D – vitamin D2 and vitamin D3. D3 (cholecalciferol) is the preferred form. It’s what’s made in our skin from sunlight; it’s also found in eggs, organ meats, animal fat and fish oil. Vitamin D2 (ergocalciferol) is synthesized by irradiating yeast or fungi. It isn’t generally found in the human body. Because it’s easier and less expensive to manufacture, D2 is the form most often used for food fortification and in medications. But it’s more difficult for the body to utilize and may even be detrimental.
Although it’s often assumed that D3 and D2 are biologically equivalent in the human body, 
they’re not. They break down into different metabolites, the effects of which are not entirely known. Also, although D3 binds well with vitamin D-binding protein (DBP), a specific carrier for vitamin D in the blood that makes sure it goes where it’s supposed to go, D2 doesn’t. The ramifications of this are unknown, but it’s hypothesized that D2 may go places it shouldn’t.
D2 has been responsible for every known case of vitamin D toxicity in which dose amount was intentional. (Toxicity reports concerning D3 have all been accidental overdoses.)
Last year, Bjelakovic and colleagues analyzed 50 randomized studies involving more than 94,000 participants to compare mortality rates between D3 and D2. They found a 6% relative risk reduction in mortality with D3 supplementation, and a 2% risk increase with D2.
The evidence, as well as common sense, indicates that the form of vitamin D our own skin manufactures from sunlight would be best as a supplement. That form is vitamin D3. At Beyond Health, we take it even a step further. There are different forms of vitamin D3, and our D3 supplements are in the best and most bioactive of these forms. Beyond Health vitamin D3 is available in our multi, our Bone Support, cod liver oil, and gel caps.