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    Ingredient guide · Ingredient reference

    What an ADK supplement contains: check A, D and K separately

    ADK usually names a combination of vitamins A, D and K. A label may use D3 and K2, but the letters do not specify one universal formula or dose.

    Read the evidence ↓

    Supplement Science Insights Editorial Team

    Published September 23, 2026

    The letters need their ingredient forms

    An archived ADK 5 label in NIH’s Dietary Supplement Label Database lists vitamin A as retinyl palmitate, vitamin D3 and vitamin K2 as MK-4 plus MK-7. That establishes one example of the combination, not the contents of every product sold under an ADK name or its current retail formulation. K2 itself is a family of menaquinones, not a single ingredient amount. [1][2]

    Normal functions do not establish a universal need for the combination

    Vitamin A supports functions including vision and cellular development. Vitamin D helps regulate calcium absorption and bone mineralization, while vitamin K supports activation of proteins involved in clotting and bone metabolism. These roles do not by themselves establish that a combined capsule improves outcomes for everyone. [3][4][2]

    Excess preformed vitamin A is hazardous, especially during pregnancy; excess vitamin D can raise blood calcium. People using warfarin need consistent vitamin K intake and should discuss changes with their clinician. A combination does not cancel the risks of its components. Include other supplements when checking the totals. [3][4][2]

    A hypothetical overlap check

    Suppose an ADK product and a separate multivitamin both contain vitamin D. Add the vitamin D amounts for the actual servings taken, converting units if necessary. Then perform separate checks for vitamin A and vitamin K. Do not combine the three amounts into one total: they are different nutrients, and their forms and units matter. [3][4][2]

    Hypothetical example — keep a combination supplement audit nutrient-specific
    Item to compareWhat to record
    Vitamin AAmount and preformed versus carotenoid source
    Vitamin DTotal from all products, in one unit
    Vitamin KForm, amount and anticoagulant context
    What an ADK supplement contains: check A, D and K separately — original article outline diagram
    Original editorial diagram of this article’s sections; no product photograph or clinical finding is depicted.

    Sources for this article

    1. ADK 5 label archived in NIH DSLD
      Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product.
    2. Vitamin K - Health Professional Fact Sheet
      Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product.
    3. Vitamin A and Carotenoids - Health Professional Fact Sheet
      Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product.
    4. Vitamin D - Health Professional Fact Sheet
      Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product.