Ahead, learn more about vitamin D2 vs D3 supplements to find out which one you should be taking. Plus, experts explain what to know about safe dosages and why doctors may prescribe one over the other.<\/p>\n
Vitamin D2 vs vitamin D3<\/p>\n
Let\u2019s start here: What is the difference between D2 and D3? \u2018People get confused about D2 and D3 because they have heard about multiple B vitamins, like B9 and B12<\/a>,\u2019 says Carol Haggans<\/a>, a scientific and health communications consultant in the NIH Office of Dietary Supplements. \u2018Those different B vitamins are actually distinctly different nutrients.\u2019 Vitamin B9, for example, is folate, which is recommended for pregnant women to prevent birth defects; B12<\/a> is cobalamin, which works to keep your blood and nerve cells healthy, and helps make DNA.<\/p>\n Vitamin D2 and D3, however, are not different nutrients. \u2018They are essentially the same compound,\u2019 says Carol, with only a slight chemical difference in their side chain structure. Still, while both are vitamin D and can help you raise your blood levels, they\u2019re not exactly the same.<\/p>\n Vitamin D3<\/p>\n Is called cholecalciferolD3 is what your body produces when your skin is exposed to sunlight\u200bIt can also be found in fish (fatty ones such as trout, salmon, tuna and mackerel) and fish liver oils, as well as other animal products.It is the version most often used in fortified foods, such as milk, cereal and orange juice, says Carol.D3 supplements are made from an irradiated compound in lanolin, which comes from sheep wool (though there is an animal-free version made from lichen)<\/p>\n Vitamin D2<\/p>\n Is called ergocalciferolYou can only get it by eating fortified food or dietary supplements (not from sunlight)D2 supplements are derived from plant products, specifically a compound in yeast that has been zapped with UV lightIt can sometimes be found in mushrooms, particularly those that are treated with UV-light to up their D2 content Plant-based foods are often fortified with D2, though many cereals and orange juices have D3 Is it better to take vitamin D3 supplements instead of D2?<\/p>\n To be clear: both forms of vitamin D help you absorb calcium, which is key for the health of your bones. Your muscles and nerves need it to function, and it helps to support your immune system. But \u2018Vitamin D3 is more bioavailable (aka has a stronger ability to be absorbed and used in the body<\/a>), which is why people tend to prefer vitamin D3,\u2019 says Dr JoAnn Manson<\/a>, a professor of medicine at Harvard Medical School and chief of the Division of Preventive Medicine at Brigham and Women\u2019s Hospital in Boston.<\/p>\n When researchers<\/a> had folks take the vitamin D2 and D3 at the levels most people take, \u2018There was a greater rise in the blood levels of vitamin D3,\u2019 she says, which is how they know if you have sufficient amounts to keep you well. \u2018There is evidence that D3 increases serum levels better, and that vitamin D levels maintain those higher levels longer than D2,\u2019 agrees Carol.<\/p>\n That said, both vitamin D3 and D2 are well absorbed in the gut, and both work well to raise blood levels of vitamin D. \u2018It\u2019s not a tremendous difference \u2013 it\u2019s not like [D3 is] twice as bioavailable as D2,\u2019 says Dr Manson, who adds that it\u2019s hard to precisely measure the effects of each supplement in the blood because people get vitamin D in other ways, such as through sun exposure and food.<\/p>\n One thing to keep in mind: Vitamin D2 supplements are derived from plant materials, so if you follow a vegan diet or avoid animal products for other reasons, D2 is a better choice for you. D2 is sometimes added to plant-based products. \u2018Most fortified products will indicate what form of vitamin D they used,\u2019 says Carol. If you don\u2019t see it indicated on the label of food or supplements, contact the manufacturer, who should be able to tell you.<\/p>\n Why do doctors prescribe vitamin D2 instead of D3?<\/p>\n They don\u2019t always, and for most people, D3 is a better option because it is more effective in raising your blood levels when you supplement daily, says Dr Manson.<\/p>\n But if someone needs a bolus dose (that is, a very high dose given over a short period of time to correct a deficiency) doctors sometimes use D2, says Dr Manson, as it has historically been available in very high doses.<\/p>\n Keep in mind: You should never take large doses of either form of vitamin D unless your doctor specifically prescribes it. \u2018You don\u2019t want to go on anything above the upper limit for any length of time,\u2019 says Carol. (For healthy people between 12 months and 70 years of age the recommended daily dose<\/a> is 600 IU, but Dr Manson\u2019s research indicates that it is safe to take 1,000-2,000 IU a day \u2018as a type of insurance\u2019 to make sure you\u2019re getting enough, she says.) Under no circumstances, says Dr Manson, should you exceed 4,000 IU of vitamin D in a day, including all sources. Very high levels can cause vomiting, muscle issues, pain and confusion, among other things, according to the NIH<\/a>.<\/p>\n If your doctor recommends a supplement, it’s wise to ask how much to take and when your blood will be next checked to make sure your levels have been raised sufficiently, says Carol. \u2018You might only need to for a period of time to boost levels up,\u2019 she adds.<\/p>\n Bottom line: it doesn\u2019t much matter which you take, unless you want to avoid animal products, says Dr Manson, in which case D2 is a better choice. D3 is better at raising blood levels of vitamin D, but D2 also works well. The main thing, says Dr Manson, is to take whichever you choose along with a bit of food that contains fat. That\u2019s because vitamin D is absorbed better with fat, and explains why one formulation you\u2019ll see in the vitamin aisle is gel caps containing oil. As with all supplements, choose your brands carefully. <\/p>\n![\"Headshot](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/09\/39a5aaae-bfe6-43a4-8697-b13c9c4438ba_1660666526.file.png\" "\\"Headshot")
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