Vitamin D plus K combinations: amounts and labeling standards disclosed

On a rainy Saturday, I pulled two “D + K” supplement bottles from my kitchen shelf and realized I couldn’t explain what their labels truly promised. Not whether they would “fix” anything—that’s never the point—but what the numbers and words were actually telling me. I wanted to map out, in plain language, how much vitamin D and K typically appear together, what U.S. labels are required to disclose, and where the fine print matters. If you’ve also stared at a Supplement Facts panel wondering what counts as “enough” and what the units mean, this is me writing down everything I wish I’d known sooner.

Why D and K show up together in the first place

What finally made this pairing click for me was noticing that both vitamins quietly orbit bone and calcium metabolism, just in different ways. Vitamin D helps us absorb calcium from the gut. Vitamin K (especially K1 and K2 forms) activates proteins like osteocalcin so that calcium gets used in the right places. That synergy is the narrative behind many “D3 + K2” capsules. Still, synergy isn’t a free pass to take more; labels are guides, not guarantees. A high-value takeaway that helped me: most multivitamins don’t combine the higher standalone doses you see in “D3 + K2” specialty products, and that’s OK—DVs (Daily Values) are designed for general labeling, not individualized therapy.

• Vitamin D on U.S. labels must be listed in micrograms (mcg), with International Units (IU) in parentheses if provided (1 mcg = 40 IU). See FDA’s labeling guidance here.
• Vitamin K is labeled in mcg; labels may optionally note the form (e.g., “as menaquinone-7”). The %DV is based on FDA’s Daily Value. Details live in 21 CFR 101.36 and related guidance; a starting point is the eCFR text here.
• I remind myself that labels cannot promise cures. Structure/function claims (like “supports bone health”) must carry the well-known FDA disclaimer.

Translating the numbers on a Supplement Facts panel

When I read labels now, I do it in three passes: what, how much, and how that fits into my day. This keeps me honest and prevents cherry-picking a single big number that “sounds” impressive.

• What: Find the line for “Vitamin D” (often specified as D₃, cholecalciferol). Find “Vitamin K” (may be K1/phylloquinone or K2 forms like MK-7). If the form is noted, that’s a transparency green flag.
• How much: Check the amount per serving in mcg. For vitamin D, manufacturers may put IU in parentheses. FDA’s Q&A on label compliance explains these conventions here.
• How it fits: Look at %DV. As of the revised label rules, the DV for vitamin D is 20 mcg (800 IU), and for vitamin K it’s 120 mcg. A product listing 25 mcg (1,000 IU) D is 125% DV; one listing 90 mcg K is 75% DV. (Daily Values are labeling references, not personal prescriptions.)

Quick sense-making examples I’ve actually seen on shelves:

• “D3 + K2” softgels with 25–125 mcg (1,000–5,000 IU) D and 90–120 mcg K2 (MK-7). These tend to be single-ingredient–style combos and sit above 100% DV for D.
• General multivitamins more often carry 10–20 mcg (400–800 IU) D and ~80–120 mcg K (sometimes K1, sometimes a blend). Many multis skip K entirely, especially those meant to be compatible with warfarin; the Supplement Facts will show you.

What’s required on the label and what’s optional

Understanding the “musts” versus “mays” lowered my anxiety. A few rules-of-thumb I keep in my notes (and double-check against FDA material before I buy):

• Mandatory basics: “Supplement Facts” title; serving size; the amount per serving and %DV for vitamins with established DVs (vitamin D, vitamin K). This is codified at 21 CFR 101.36; FDA’s small-entity guide is a readable overview here.
• Units: D must be in mcg; IU may appear in parentheses. The conversion is fixed at 1 mcg = 40 IU per FDA’s revision document PDF.
• Forms: You’ll often see “Vitamin D (as cholecalciferol).” For K, manufacturers can list “Vitamin K (as phylloquinone)” or “(as menaquinone-7),” but the %DV is for total vitamin K, not separate DVs by form.
• Proprietary blends: Vitamins with DVs cannot hide their amounts inside a blend. If a product includes vitamin D or K, those amounts must be declared with %DV on the panel; blends are for ingredients without established DVs.
• Quality marks: Not required, but third-party verification (e.g., the USP Verified Mark) adds assurance that what’s on the label matches what’s in the bottle. USP explains its program here.

How I sanity-check “appropriate” amounts for me

There’s no one-size-fits-all dose, so I built a personal decision routine. It’s part detective work, part self-awareness, and part respect for my actual diet and prescriptions.

• Step 1 Notice: Am I already getting vitamin D from a multivitamin or fortified foods? Do I spend time outdoors? Do I have a recent blood test (25(OH)D)? I glance at NIH’s vitamin D fact sheet for ballpark context on intakes and safety here.
• Step 2 Compare: If I’m looking at a “D + K” product, I compare %DV to see if it’s doubling up with my multi. A D+K softgel with 125 mcg (5,000 IU) D might be far above what I need alongside a multivitamin; more isn’t always better.
• Step 3 Confirm: If I take blood thinners (like warfarin), I pause and talk to my clinician. Vitamin K intake consistency matters; NIH’s K fact sheet spells out the warfarin interaction simply here.

Personal note: I once assumed more D would give me more “energy.” Reading the NIH sheet taught me that excessive vitamin D can raise calcium too high, and that risks are real at high supplemental intakes. That quieted the temptation to chase the biggest label number.

Typical pairings I see—and how I read them

Here’s how I skim the most common D+K pairings on U.S. shelves without getting lost in marketing adjectives.

• D3 25–50 mcg with K2 90 mcg (MK-7): A popular “everyday” strength. My read: a single capsule can exceed 100% DV for D while landing below or near DV for K. I check what else I’m taking to avoid stacking D above my goals.
• D3 100–125 mcg with K2 120 mcg: A higher-D pairing. My read: this can be appropriate only if I have a specific reason (and a clinician onboard) to target a higher D intake; otherwise it’s easy to overdo.
• Multivitamin with modest D and K (e.g., D 10–20 mcg; K 80–120 mcg): My read: a general-coverage baseline; I avoid adding a second D+K unless I know why.
• Multivitamins without K: Sometimes formulated to be warfarin-friendly. My read: if I’m not on warfarin, the absence of K isn’t automatically a plus or minus—it just means I might get K primarily from food.

I also look for serving size tricks (e.g., “2 capsules”). A perfect-looking amount per serving can be half as much as I think if I only ever take one capsule. That’s not sinister, just good to notice.

Red and amber flags that make me slow down

Shopping taught me to treat certain signals as green lights for more questions, not as automatic deal-breakers.

• Very high vitamin D per serving (e.g., 100–125 mcg or 4,000–5,000 IU) sold as “daily” for everyone. Amber: sometimes appropriate, but it’s above DV and can be unnecessary for many of us. NIH’s D sheet has the safety context and UL discussion here.
• Labeling that omits the form of K when the front says “K2.” Amber: not a violation, but I prefer panels that state “menaquinone-7.” Transparency wins.
• Big claims without the standard disclaimer. Supplements can’t promise to diagnose, treat, cure, or prevent disease. FDA’s labeling guide is helpful for spotting compliant language here.
• No third-party testing or GMP mentions. Optional, but I’ve grown to appreciate programs like USP Verified that check contents and purity; overview here.

How I build a simple “label-reading loop”

I keep a tiny checklist on my phone for any supplement aisle trip. It sounds nerdy, but it saves me from impulse buys.

• Read Supplement Facts line by line: Vitamin D amount (mcg and IU), Vitamin K amount (mcg), forms, %DV, serving size.
• Scan Other Ingredients for anything I try to avoid (excipients don’t make a product “bad,” but unnecessary extras aren’t a selling point for me).
• Confirm overlaps with my multivitamin or fortified foods to avoid stacking dosages.
• Look for quality signals (USP Verified or similar) and a way to contact the manufacturer for a Certificate of Analysis if available.
• When in doubt, I park the bottle and re-check FDA/NIH pages at home rather than guessing in the aisle.

The personal parts I’m keeping

After a few months of paying closer attention, I’m keeping three grounded principles on my fridge door:

• Label literacy beats label loyalty: I don’t marry a brand; I read the panel.
• DV is a compass, not a command: It helps me compare products, but my needs still live with my clinician and my labs.
• Consistency matters more than perfection: For vitamin K in particular, day-to-day steadiness (especially on warfarin) is more meaningful than chasing the “optimal” number.

FAQ

1) How much vitamin D and K should a typical “D + K” capsule have?
Answer: There’s no universal target. Many “D3 + K2” products range from 25–125 mcg (1,000–5,000 IU) of D and 90–120 mcg of K2 per serving. Compare the %DV and consider what you already take. For safety context and upper limits, see NIH’s D and K fact sheets for professionals D and K.

2) Do labels have to show vitamin D in IU or mcg?
Answer: U.S. labels must declare vitamin D in mcg. IU may appear in parentheses (1 mcg = 40 IU). FDA outlines this in its label revision materials here.

3) Is vitamin K2 (MK-7) treated differently from K1 on labels?
Answer: The %DV is for total vitamin K. Brands may optionally list the form (e.g., “as MK-7”) for transparency, but there’s not a separate DV for K2 versus K1. Labeling rules are in 21 CFR 101.36; see the eCFR page here.

4) Can a company hide vitamin D or K inside a proprietary blend?
Answer: No. Vitamins and minerals with established DVs (like D and K) must disclose their amounts and %DV on the panel. Proprietary blends are for ingredients without established DVs. FDA’s labeling Q&A summarizes the framework here.

5) How do I know if what’s on the label matches what’s in the bottle?
Answer: Consider brands that use third-party testing programs (USP Verified is one), check for batch-specific Certificates of Analysis when offered, and review FDA/NIH resources before buying. USP explains its verification program here.

Sources & References

• 21 CFR 101.36 (eCFR)
• FDA Label Revision Q&A (2020, PDF)
• FDA Small Entity Guide (2020)
• NIH ODS Vitamin D (2025)
• NIH ODS Vitamin K (2021)

This blog is a personal journal and for general information only. It is not a substitute for professional medical advice, diagnosis, or treatment, and it does not create a doctor–patient relationship. Always seek the advice of a licensed clinician for questions about your health. If you may be experiencing an emergency, call your local emergency number immediately (e.g., 911 [US], 119).