Vitamin D3 vs D2, Drops vs Tablets, and Vegan Options

Once you have decided that a vitamin D supplement is worth considering, three choices come up on the shelf: D3 or D2, a liquid or a pill, and animal-derived or vegan. This guide sets out what the research reviews, the FDA and the American Academy of Pediatrics (AAP) say about each, so you can compare them with the label of the product in front of you. It is general information for healthy adults and, where noted, for parents, not medical advice. For the full set of buying checks, see our buying guide.

What D2 and D3 are

The FDA describes vitamin D as a group of fat-soluble compounds whose two major forms are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Supplements contain one or the other, and the Supplement Facts panel or ingredient list names which, for example "Vitamin D3 (as cholecalciferol)". For converting units, the FDA's guidance treats the two as bioequivalent, which is why a label in mcg looks the same for both.

What the comparisons find

MedlinePlus says both types increase vitamin D in your blood, but D3 might raise it higher and for longer than D2. The NIH Office of Dietary Supplements health professional fact sheet likewise says that D3 raises blood levels more and keeps them up longer.

A 2024 meta-analysis in Advances in Nutrition, by van den Heuvel and colleagues, pooled 17 randomized trials with 20 D2-versus-D3 comparisons in healthy adults, including 554 people given D2 and 576 given D3. D3 raised total blood 25-hydroxyvitamin D more than D2. In the 12 comparisons that used daily doses and a laboratory method called LC-MS/MS, the rise in the D2 groups was 10.39 nmol/L lower, about 40% less. The gap was bigger with weekly dosing, though only three such studies were included. Body mass index was the strongest modifier: in participants mainly with a BMI of 25 or below D3 clearly produced the bigger rise, while in those mainly with overweight or obesity the two did not differ. The authors say BMI and the starting blood level should be considered when comparing them.

Two cautions. These trials measure a blood marker in healthy adults, not how any person feels or whether the supplement does anything for them. And if a clinician has prescribed a specific form and dose, follow that, not this article.

Where each form comes from, and vegan options

The Vegetarian Resource Group explained in 2011 that mushrooms produce vitamin D2 when exposed to ultraviolet light, that D3 is usually derived from lanolin in sheep's wool, and that lichen-derived D3 is an exception. It said it was not aware of an all-plant D3 apart from lichen, and it questioned a brand's mushroom-D3 claim for lack of an explanation. That post is old and brand-specific, so treat it as background and not as a list of products. For a vegan or vegetarian diet:

• Look for D3 that names lichen as its source, or for D2.
• Read the ingredient statement too. The FDA's labeling guide says fillers and excipients are listed there, in descending order by weight, and one of its examples lists gelatin, a common capsule material. A softgel shell may be gelatin even when the vitamin D is plant-sourced.
• If a pack names a vegan certification mark, confirm it with the certifier.

Here are searches for vegan vitamin D3 from lichen on Amazon (opens in a new tab) and vitamin D2 ergocalciferol on Amazon (opens in a new tab). They match words, so the label has to confirm the source.

Softgels, capsules and tablets

These are the standard formats, with one unit per serving in most cases. Check the serving size, because some products use two. MedlinePlus says you absorb vitamin D better when you take it with a meal or snack that includes some fat, and that applies to any format. None of the sources we read rank softgels above tablets or capsules, so choose by amount, ingredients and outside verification. In the 2013 JAMA Internal Medicine research letter on 55 bottles of over-the-counter vitamin D and a compounded product, contents ranged from 9% to 146% of the label across the products tested, and the one maker with the USP Verified Mark was generally more accurate. A search such as vitamin D3 softgels on Amazon (opens in a new tab) shows the range of listings.

Gummies and chewables

Gummies and chewables are easier to swallow, and they are also candy-like, so read the sugars and sweeteners in the ingredient statement and the serving size in the panel, where two or more pieces may make one serving. The same research letter is a reason to want outside verification for any format. Some products are labeled for children, and the AAP says chewable vitamins are generally regarded as safe for children over the age of three who can chew hard foods and candy. For younger children, and for the dose, ask your pediatrician.

Liquid drops

Liquids let you adjust the amount in small steps, and they are the format the AAP recommends for babies. The AAP says breastfed and partially breastfed infants should get 400 IU a day, beginning in the first few days of life, and that babies younger than 12 months need 400 IU each day. The AAP notes that some liquid preparations give 400 IU in one-half or one milliliter and that others give 400 IU in a single drop. From those two statements it follows that the same dropper or drop count can deliver very different amounts depending on the product. So:

• Read the amount per serving and the serving, in drops or milliliters, on the label of the product you have.
• Use only the dropper or dispenser that comes with it.
• Do not switch brands and keep the old number of drops.
• Keep supplements out of a child's reach, as the AAP advises.
• Ask your pediatrician before starting, and again if you change products.

Adults can use drops the same way: confirm the amount in mcg per drop or per milliliter, and do the arithmetic against the upper limit in our dose guide. Vitamin D3 liquid drops on Amazon (opens in a new tab) is a search for them. Some drops need refrigeration after opening, so follow the storage directions on the bottle.

A short checklist

• Form: D3 or D2, named in the panel.
• Amount: mcg per serving, with IU in parentheses if given; 1 mcg = 40 IU.
• Serving: how many units or drops make one.
• Ingredients: capsule shell, sweeteners, oils and allergens.
• Outside verification: a USP or NSF mark you can confirm with the program.

The FDA does not approve or test supplements before they are sold, and it advises talking to your doctor, pharmacist or other health care professional before you buy or use one. If you are pregnant, buying for a child, have kidney disease or take medicines, ask first. The label on your pack is the authority on dose, ingredients and warnings.