Vitamin ADK Benefits: What Each Vitamin Does and What a Label Shows

Vitamin ADK benefits are best understood as the separate roles of three vitamins. NIH’s Office of Dietary Supplements (ODS) says vitamin A is important for normal vision, the immune system, reproduction, and growth and development; vitamin D helps the body absorb calcium; and vitamin K is important for blood clotting and healthy bones. [1] [2] [3] The studies ODS describes mostly tested one vitamin at a time, in specific groups of people and at specific amounts, so they do not show what a finished A, D and K blend does. [4] [5] Claims printed on supplement labels are not pre-approved by the U.S. Food and Drug Administration (FDA); the manufacturer must have substantiation for them. [6]

This page is general education about reading labels. It does not recommend any product or amount. The five A, D and K labels compared below declare 125 to 250 mcg of vitamin D and 90 to 2,800 mcg of vitamin K per serving (the vitamin K total is our calculation), and one declares 3,000 mcg RAE of preformed vitamin A, the same as the adult upper limit for all sources combined. [7] [8] [9] [1]

Safety first: if you take warfarin or another blood thinner, are pregnant, could become pregnant or are breastfeeding, smoke or used to smoke, or take orlistat, a statin, a steroid such as prednisone, a thiazide diuretic, acitretin or bexarotene, ask your doctor or pharmacist before using any product with vitamin A, D or K. ODS says that for people who take warfarin, a sudden change in vitamin K intake can cause dangerous bleeding or blood clots, and that too much preformed vitamin A during pregnancy can cause birth defects. [3] [1] ODS lists the medicine interactions named here on its consumer fact sheets. [1] [2] [3] [10]

Use the ingredient-label checklist

What each vitamin does, and who was studied

Each row separates the role ODS describes from the people and amounts in the research it summarizes. A study of one vitamin, in one group, at one amount, does not establish what a product combining three vitamins at different amounts does.

What a claim on a blend label means

FDA says structure/function claims may describe the role of a nutrient or dietary ingredient intended to affect the normal structure or function of the human body. These claims are not pre-approved by FDA; the manufacturer must have substantiation that a claim is truthful and not misleading, and must notify FDA of its text no later than 30 days after marketing the product with it. [6] A label with such a claim must state that FDA has not evaluated it, and that the product is not intended to “diagnose, treat, cure or prevent any disease.” [6]

Labels A and D below make statements about what the combination does, and labels D and E make statements about how their forms are absorbed. [7] [12] [9] A statement on a label is the manufacturer’s description. It is not a study of that blend, and it does not show that a blend works better than separate vitamins or that it suits you.

Five vitamin ADK labels compared

Method. The table uses five on-market vitamin A, D and K combination records from the NIH Dietary Supplement Label Database (DSLD), which captures the information printed on supplement labels sold in the United States, including products that are no longer sold, and identifies each by its DSLD record number. [13] A record shows what a label declares per labeled serving, not what a product has been tested to contain, so check any entry against the label you have. Conversions, totals and percentages marked “our calculation” use the ODS conversion factors and FDA Daily Values cited on this page.

Each label is above the vitamin D upper limit by itself. All five labels declare at least 125 mcg (5,000 IU) of vitamin D per serving, and label B declares 250 mcg. [7] [8] [14] [12] [9] ODS lists 100 mcg (4,000 IU) a day as the upper limit for ages 9 and older, counting food, beverages and supplements together, and notes that a health care provider might recommend more than the upper limit for a period of time to correct a deficiency. [2] Label B’s own precautions say the product is not intended for long-term use and should be used under a doctor’s supervision. [8] An upper limit is a ceiling, not a recommended amount; ask your doctor whether any amount suits you, and for how long.

IU on an older label. Label C declares vitamins A and D only in international units (IU), and its percentages match the reference amounts in the 2015 edition of the federal labeling rule: 5,000 IU for vitamin A, 400 IU for vitamin D and 80 mcg for vitamin K. [14] [15] The current rule requires vitamin D in mcg, with IU optional in parentheses, and FDA’s current Daily Values are 900 mcg RAE for vitamin A, 20 mcg for vitamin D and 120 mcg for vitamin K. [16] [17] With the ODS conversions (1 IU of retinol is 0.3 mcg RAE; 1 mcg of vitamin D is 40 IU), label C’s amounts come to about 1,500 mcg RAE of vitamin A and 125 mcg of vitamin D (our calculation). [11] [4] Its record was entered in 2022, so the label in circulation may differ; ask the manufacturer if your label still shows IU only.

The vitamin A form decides what counts toward the upper limit. The adult upper limit of 3,000 mcg a day applies to preformed vitamin A, such as retinyl palmitate, from all sources; ODS lists no upper limit for beta-carotene. [1] All five labels use retinyl palmitate, and label D adds 7 mcg RAE of beta-carotene. [12] Label A’s 3,000 mcg RAE equals the adult upper limit on its own (our comparison). [7] [1] ODS says amounts of vitamin A in supplements vary widely and that 3,000 mcg RAE is common. [11] The federal rule lets a label show how much vitamin A is present as beta-carotene, as in “Vitamin A (90% as beta-carotene)”, and defines 1 mcg RAE as 2 mcg of supplemental beta-carotene. [16] [18]

One Daily Value for vitamin K, several forms. FDA’s Daily Value table gives a single figure for vitamin K, 120 mcg, with no separate entry for K1 or K2. [17] Labels A, B, D and E mark their K2 lines “Daily Value not established”, while label E gives its K1 line a %DV of 833%. [7] [8] [12] [9] Measured against 120 mcg, the vitamin K on the five labels runs from 75% (label A) to about 2,333% (label E’s 2,800 mcg total) of the Daily Value (our calculation). Ask the manufacturer how a K2 line’s %DV was handled. ODS lists phylloquinone and phytonadione (K1) and menaquinone-4 and menaquinone-7 (K2) as common supplement forms. [3] It says multivitamins typically contain less than 75% of the Daily Value, while products with vitamin K alone or with a few other nutrients range more widely, some providing 4,050 mcg. [5]

Warnings differ. In their DSLD records, labels A and B name warfarin in their warnings, and labels A, B and E carry pregnancy cautions; the records for labels C and D show no warning text. [7] [8] [9] [14] [12] A missing warning does not mean a product is suitable for someone who takes a blood thinner or is pregnant. Label A also warns that vitamin A from retinol at 10,000 IU or more is known to cause birth defects; 10,000 IU of retinol is 3,000 mcg RAE, the amount label A declares (our calculation). [7] [11]

Overlap with multivitamins and other products

ODS says most multivitamins contain vitamin A, often 750 to 1,050 mcg RAE, and vitamin K, typically less than 75% of the Daily Value. [11] [5] It notes that people who take multivitamins and other supplements and also eat fortified foods and beverages might get some nutrients above the upper limit, and that when intakes exceed the upper limit, the potential risk of adverse effects increases. [10] Vitamin D must be listed on Nutrition Facts labels, while vitamins A and K may be listed voluntarily unless they have been added to the food. [17] For practice finding them on food packages, see the food label reading worksheet.

Hypothetical example. Suppose someone used one labeled serving of label A along with a multivitamin declaring 900 mcg RAE of vitamin A, all as retinyl acetate, and 20 mcg of vitamin D. Together they would come to 3,900 mcg RAE of preformed vitamin A and 145 mcg of vitamin D before counting food, both above the adult upper limits ODS lists (our calculation). [7] [1] [2] Bring every label to your pharmacist or doctor rather than comparing totals with a ceiling yourself.

Single-nutrient products overlap with combinations too. For how a B-vitamin label lists its forms, see the guide to a plant based vitamin B complex.

Medicine questions to bring to your pharmacist

• Warfarin. ODS says people who take warfarin should keep the amount of vitamin K from food and supplements about the same every day. [3] Warfarin prescribing information lists increased vitamin K intake among factors that may decrease the INR response, advises a consistent amount of vitamin K, and calls for more frequent INR monitoring when other drugs, including botanicals, are started or stopped. [19] Its patient information asks people to tell their provider about all their medicines, including vitamins and herbal supplements. [19]
• Orlistat. This weight-loss medicine can decrease the absorption of vitamins A, D and K. [1] [2] [3]
• Acitretin and bexarotene. These medicines are made from vitamin A, and ODS says using them with a vitamin A supplement could cause dangerously high levels of vitamin A in the blood. [1]
• Statins, steroids and thiazide diuretics. ODS says statins might not work as well with high-dose vitamin D, steroids such as prednisone can lower blood levels of vitamin D, and thiazide diuretics could raise blood calcium too high with vitamin D supplements. [2]
• Bile acid sequestrants and antibiotics. Bile acid sequestrants such as cholestyramine and colestipol can reduce how much vitamin K the body absorbs, and antibiotics used for more than a few weeks may reduce the vitamin K made in the gut. [3]
• Calcium. ODS says taking calcium supplements in combination with vitamin D supplements may increase the risk of certain adverse effects. [4]

This list is not complete. DailyMed posts labeling that companies submit to FDA; the National Library of Medicine (NLM) does not review it before publication. [20]

Ingredient-label checklist for vitamin ADK

Use these steps with each physical label in front of you, and write down the date you checked.

• Find the serving size. Note how many softgels, capsules or drops make one serving; every amount on the panel applies to that serving. [12]
• Name the vitamin A form. Retinyl palmitate or retinyl acetate is preformed vitamin A, which counts toward the 3,000 mcg adult upper limit; beta-carotene has no upper limit. [1]
• Convert any IU. For retinol forms, multiply IU by 0.3 to get mcg RAE; for vitamin D, divide IU by 40 to get mcg. [11] [4]
• Add every vitamin K line. A label may list K1 and K2, or MK-4 and MK-7, on separate lines; add them for the total. [12] [9]
• Check the %DV basis. Compare amounts with the current Daily Values of 900 mcg RAE, 20 mcg and 120 mcg. A %DV of 100% for 5,000 IU of vitamin A reflects the older reference amount. [17] [15]
• Read the warnings. Look for blood-thinner and pregnancy statements, and remember that a missing warning is not a clearance. [7] [8]
• Read claims as the manufacturer’s. Statements about the combination or about absorption are not evaluated by FDA. [6]
• List every product. Include multivitamins, other vitamin products and fortified foods, with the servings you actually use. [10]
• Bring the list to your pharmacist or doctor. Mention any blood thinner, pregnancy or plans for one, smoking history and the medicines above. [3] [1] [10]
• Match the record to your container. DSLD includes labels for products no longer sold, so compare any entry with the label you have. [13]

Safety notes

• ODS says too much preformed vitamin A can cause severe headache, blurred vision, nausea, dizziness, muscle aches and problems with coordination. [1]
• If you are or might be pregnant, or are breastfeeding, ODS says you should not take high-dose supplements of preformed vitamin A. [1]
• Smokers, former smokers and people exposed to asbestos who take high-dose beta-carotene supplements have shown a higher risk of lung cancer in several studies, and ODS says smokers and possibly former smokers should avoid multivitamins with large amounts of beta-carotene or vitamin A. [1] [10]
• ODS says high levels of vitamin D are almost always caused by too much vitamin D from dietary supplements, and that very high blood levels can cause nausea, vomiting, muscle weakness, confusion, pain, loss of appetite, dehydration, excessive urination and thirst, and kidney stones. [2]
• No upper limit has been set for vitamin K, but the warfarin interaction applies to vitamin K from both food and supplements. [5] [3]

Where to go next

Whether you need vitamin A, D or K, and in what form or amount, is a question for your doctor or pharmacist. More label guides are listed under Ingredients and labels.

Common questions

What are the benefits of vitamin ADK?

The roles ODS describes belong to each vitamin: vitamin A for normal vision, the immune system, reproduction and growth; vitamin D for calcium absorption; and vitamin K for blood clotting and healthy bones. [1] [2] [3] The trials described on this page tested single vitamins, not a finished A, D and K blend, and VITAL found no fewer fractures or cardiovascular events in mostly vitamin D–sufficient older adults. [4]

Is vitamin ADK safe with blood thinners?

Ask your doctor before using it. ODS says people who take warfarin should keep their vitamin K intake about the same every day, because a sudden change can cause dangerous bleeding or blood clots. [3] Warfarin labeling lists increased vitamin K intake among factors that may decrease the INR response. [19]

Can vitamin ADK overlap with a multivitamin?

Yes. Most multivitamins contain vitamins A and K, and the upper limits for preformed vitamin A and vitamin D count every source together. [11] [5] [1] [2] Bring all your labels to a pharmacist.

Why does my label show IU instead of mcg?

Older labels used IU. The current rule requires vitamin D in mcg, with IU optional in parentheses. [16] To convert, 1 IU of retinol is 0.3 mcg RAE and 1 mcg of vitamin D is 40 IU. [11] [4]

Why does vitamin K2 say “Daily Value not established”?

FDA lists one Daily Value for vitamin K, 120 mcg, with no separate figure for K2. [17] Several labels above still mark K2 this way, so ask the manufacturer how the line was handled. [7] [8]

Is beta-carotene the same as vitamin A?

No. Beta-carotene is a provitamin A carotenoid that the body can convert to vitamin A. ODS lists no upper limit for it, but notes that high-dose beta-carotene supplements have been linked to a higher risk of lung cancer in smokers, former smokers and people exposed to asbestos. [1]

If you take warfarin or another blood thinner, are pregnant, could become pregnant or are breastfeeding, smoke, or take any of the medicines listed above, ask your doctor or pharmacist before using any product with vitamin A, D or K. [3] [1] [2]

Use the ingredient-label checklist

Sources and limitations

1. NIH Office of Dietary Supplements: Vitamin A, Fact Sheet for Consumers. Updated March 10, 2025. General consumer overview; the upper limit is a ceiling for preformed vitamin A from all sources, not a recommended amount.
2. NIH Office of Dietary Supplements: Vitamin D, Fact Sheet for Consumers. Updated November 8, 2022. General consumer overview; the upper limit counts all sources and is not a recommended amount.
3. NIH Office of Dietary Supplements: Vitamin K, Fact Sheet for Consumers. Updated March 22, 2021. General consumer overview, last updated in 2021.
4. NIH Office of Dietary Supplements: Vitamin D, Fact Sheet for Health Professionals. Updated June 27, 2025. Written for health professionals; VITAL tested vitamin D3 alone or with omega-3s in older U.S. adults who were mostly vitamin D sufficient.
5. NIH Office of Dietary Supplements: Vitamin K, Fact Sheet for Health Professionals. Updated March 29, 2021. Written for health professionals; fracture data come mostly from postmenopausal women in Japan given pharmacological doses of MK-4.
6. U.S. Food and Drug Administration: Structure/Function Claims. Content current as of March 28, 2024. Describes the legal process for label claims; a claim on a label is the manufacturer’s statement.
7. NIH Dietary Supplement Label Database: record 337652, vitamin A, D3 and K2 softgel. Entered August 22, 2025. Label text as recorded, not a test of contents.
8. NIH Dietary Supplement Label Database: record 322150, vitamin A, D3 and K2 capsule. Entered March 25, 2025. Label text as recorded, not a test of contents.
9. NIH Dietary Supplement Label Database: record 333459, vitamin A, D3, K1 and K2 capsule. Entered July 24, 2025. Label text as recorded, not a test of contents.
10. NIH Office of Dietary Supplements: Multivitamin/mineral Supplements, Fact Sheet for Health Professionals. Updated July 17, 2024. Written for health professionals; cited for overlap, upper-limit and smoking cautions.
11. NIH Office of Dietary Supplements: Vitamin A and Carotenoids, Fact Sheet for Health Professionals. Updated March 10, 2025. Written for health professionals; CARET enrolled smokers and people exposed to asbestos.
12. NIH Dietary Supplement Label Database: record 273605, vitamin A, D3 and K2 liquid. Entered March 22, 2023. Label text as recorded, not a test of contents.
13. NIH Office of Dietary Supplements: Dietary Supplement Label Database, About. Records what labels say; it does not test products, and it includes off-market labels.
14. NIH Dietary Supplement Label Database: record 278652, vitamin A, D3 and K2 capsule. Entered December 13, 2022. An older record; the label in circulation may differ.
15. U.S. Government Publishing Office: Code of Federal Regulations, 21 CFR 101.9, 2015 edition. Revised as of April 1, 2015; paragraph (c)(8)(iv). A historical edition showing reference amounts used before the current Daily Values.
16. Electronic Code of Federal Regulations: 21 CFR 101.36, Nutrition labeling of dietary supplements. eCFR text current as of October 8, 2026; paragraphs (b)(2)(i)(B)(3) and (b)(2)(ii)(B). Rules for manufacturers; they do not verify any product.
17. U.S. Food and Drug Administration: Daily Value on the Nutrition and Supplement Facts Labels. Content current as of March 5, 2024. Consumer-facing summary; one Daily Value is given for vitamin K, with no separate K1 or K2 figure.
18. Electronic Code of Federal Regulations: 21 CFR 101.9, Nutrition labeling of food. eCFR text current as of October 8, 2026; cited for the retinol activity equivalent definition in paragraph (c)(8)(iv).
19. National Library of Medicine: DailyMed, warfarin sodium tablets, prescription drug label. Labeling revised November 2022; DailyMed label information updated May 29, 2026. Prescription medicine labeling; cited for vitamin K interaction and monitoring statements only.
20. National Library of Medicine: DailyMed, About. Labeling is submitted by companies and is not reviewed by NLM before publication.