The Best Vitamin D3 K2 Supplement
The best vitamin D3 K2 supplement is Nature Made D3 + K2, about $0.42 a day. People take the pair for their bones. Its K2 is MK-7, the longer-lasting form, and an outside lab checks it. Each softgel is 5,000 IU, above the 4,000 IU daily limit, so ask your doctor first, especially if you take warfarin.
By Erin Rose Updated October 28, 2026 How we score
Our pick for: D3 + K2 in one softgel
- Dose
- 5,000 IU + 100 mcgD3 and K2 as MK-7
- A day
- $0.42Amazon price
- Bottle
- 30 softgels$12.58, about a month
- Testing list
- USP VerifiedChecked September 22, 2026
- Daily limit
- Above 4,000 IUAsk your doctor first
- Take
- With a mealOne softgel
Why we pick it It is the one D3 + K2 we track that is lab-checked and uses MK-7, the form of K2 that shows up in the blood. USP Verified checks that the bottle holds what the label says, which matters with vitamin D: pills tested in one study ranged from under 10% to about twice their label (Garg 2013).
What you give up A 30-count bottle, and it costs about $133 a year more than Horbaach, which has no outside lab check we could find. Other picks.
The best D3 + K2 for your needs
Best under the daily limit: Thorne Vitamin D + K2
Thorne’s drops give 2,000 IU of D3 a day, under the 4,000 IU limit, and are on NSF/ANSI 173. The catch is the K2: it is MK-4, 400 mcg a day. In one small study of healthy women, a 420 mcg dose of MK-7 showed up in the blood for two days, while the same dose of MK-4 did not show up at all (Sato 2012). It costs $0.11 a day, and one bottle lasts about 300 days.
Thorne Vitamin D + K2
$0.11 a day · 2,000 IU + 400 mcg MK-4
Best for the lowest cost: Horbaach D3 + K2
At $0.05 a day, Horbaach is the cheapest D3 + K2 we track, and one bottle lasts about six months. The trade-off: no outside lab check we could find. Like our pick, each softgel is 5,000 IU.
Horbaach D3 + K2
$0.05 a day · 5,000 IU + 100 mcg MK-7
Best for the K2 dose used in trials: NOW Mega D-3 & MK-7
If you want K2 at the amount studied for bone, NOW Mega has 180 mcg of MK-7 per capsule, the dose used in a 3-year bone trial in women after menopause (Knapen 2013). It costs $0.20 a day, carries 5,000 IU of D3, and has no outside lab check we could find.
NOW Mega D-3 & MK-7
$0.20 a day · 5,000 IU + 180 mcg MK-7
Is K2 worth adding?
Think of K2 as optional. The case for pairing them is about calcium: vitamin D helps you absorb it, and vitamin K turns on proteins that handle it (van Ballegooijen 2017). The trial results are small. A pooled look at 8 trials found slightly better bone density with D plus K (Kuang 2020), and no study we found compared D3 with and without K2 for fractures. We go through every trial on vitamin D with or without K2.
Is 5,000 IU too much?
It is more than most adults need. The daily need is 600 IU, or 800 IU after age 70, and the upper limit is 4,000 IU (Ross 2011). Doctors use 5,000 IU for a time to bring a low blood level up, then check it again. Almost every D3 + K2 combo we track is a 5,000 IU softgel, our pick included, so ask your doctor before you start. If your doctor has not found you low, about 2,000 IU a day covers most adults, and Thorne’s drops are the tested D3 + K2 at that level.
On warfarin? Talk to your doctor before any K2. Even 50 mcg of MK-7 a day may interfere with it (Schurgers 2007).
Read the K2 line on the label
A good label names the form, MK-7, and gives the amount in mcg. 72.5% of the 327 K2-only labels we read name MK-7; 4.3% name MK-4, and 22.3% name no form at all. The usual amount printed is 100 mcg. Our pick has 100 mcg of MK-7. Thorne’s drops are the one product here with MK-4. Few plain 5,000 IU vitamin D labels add K2 at all: 15.8% of the 95 we read in the NIH label database.
6 vitamin D3 + K2 supplements compared
Our pick leads, then the other lab-checked bottle, then everything else from lowest to highest daily cost. Buying the cheapest plain 2,000 IU D3 and the cheapest 100 mcg MK-7 we track as two bottles costs $0.13 a day.
| Supplement | Dose per day | Why it is or is not a pick |
|---|---|---|
| Nature Made D3 + K2$0.42 a day · 30 count | 5,000 IU + 100 mcg MK-7 | Our pick |
| Thorne Vitamin D + K2$0.11 a day · 1 fl oz, about 300 days | 2,000 IU + 400 mcg MK-4 | Under the limit |
| Horbaach D3 + K2$0.05 a day · 180 count | 5,000 IU + 100 mcg MK-7 | Lowest cost |
| Micro Ingredients D3 + K2$0.10 a day · 300 count | 5,000 IU + 100 mcg MK-7 | No lab check found |
| Nutricost D3 + K2$0.12 a day · 120 count | 5,000 IU + 100 mcg MK-7 | No lab check found |
| NOW Mega D-3 & MK-7$0.20 a day · 120 count | 5,000 IU + 180 mcg MK-7 | Trial dose |
Questions people ask
Do I need K2 with vitamin D3?
You can skip it. Vitamin D works on its own, and adding K2 made only a small difference to bone density in trials. The trials, one by one.
Is D3 + K2 safe with blood thinners?
If you take warfarin, talk to your doctor before any K2, because K2 can change how warfarin works. Vitamin K and warfarin.
More on vitamin D
Still deciding whether you need K2? Read vitamin D with or without K2. For D3 alone, see the best vitamin D supplement; for higher doses, 5000 IU with K2. Also: side effects and vitamin K.
How we picked
Our first filter is an outside lab check, our second is K2 as MK-7 with the dose printed, and price breaks ties. Because almost every combo is 5,000 IU, we also name the one tested option under the daily limit. Five lab programs were searched for every combo on September 22, 2026: USP Verified, NSF/ANSI 173, NSF Certified for Sport, Informed Sport and Informed Choice. Amazon prices are from October 30, 2026, and K2 amounts come from each product’s listing or NIH label. Full method.
Sources
- Knapen MH, et al. “Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women.” Osteoporos Int. 2013. PubMed 23525894
- Kuang X, et al. “The combination effect of vitamin K and vitamin D on human bone quality: a meta-analysis of randomized controlled trials.” Food Funct. 2020. PubMed 32219282
- Schurgers LJ, et al. “Vitamin K-containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7.” Blood. 2007. PubMed 17158229
- Garg S, et al. “Evaluation of vitamin D medicines and dietary supplements and the physicochemical analysis of selected formulations.” J Nutr Health Aging. 2013. PubMed 23364495
- van Ballegooijen AJ, et al. “The synergistic interplay between vitamins D and K for bone and cardiovascular health: a narrative review.” Int J Endocrinol. 2017. PubMed 29138634
- Sato T, et al. “Comparison of menaquinone-4 and menaquinone-7 bioavailability in healthy women.” Nutr J. 2012. PubMed 23140417
- Ross AC, et al. “The 2011 report on dietary reference intakes for calcium and vitamin D from the Institute of Medicine: what clinicians need to know.” J Clin Endocrinol Metab. 2011. PubMed 21118827
- Testing lists, read September 22, 2026: NSF/ANSI 173, USP Verified, NSF Certified for Sport, Informed Sport and Informed Choice. Labels: NIH Office of Dietary Supplements, Dietary Supplement Label Database (dsld.od.nih.gov).