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Immune & Bone
Vitamin D3 + K2
$20$26Save $6
5,000 IU vitamin D3 (cholecalciferol) — a dose that actually moves the needle on serum 25(OH)D
100mcg MK-7 K2 from natto — the long-chain form that stays active for 72 hours
K2 directs calcium into bones, away from arteries — D3 alone doesn't do this
Supports immune response, mood, bone density, and cardiovascular health
One soft capsule per day. Oil-based for maximum fat-soluble vitamin absorption.
Size
🚚 Ships within 24 hrs↩️ 60-day returns🔒 Secure checkout🔬 Third-party tested
Estimated delivery: Order today, receive by May 9–12. Ships from Austin, TX.
Taking D3 without K2 is like building a road without traffic signs.
About 42% of American adults are vitamin D deficient. The consequences are well-documented: weakened immune response, low mood in winter months, poor calcium absorption, and long-term risk to bone density. Most people who fix this take a vitamin D supplement. Far fewer take the right one.
Here's the problem. Vitamin D3 dramatically increases your intestinal absorption of calcium — up to 40% more than without supplementation. That calcium has to go somewhere. Without adequate vitamin K2, it often deposits in the wrong places: arterial walls, soft tissue, kidneys. K2's job, specifically through a protein called Matrix Gla Protein (MGP), is to keep calcium out of arteries. Another K2-dependent protein, osteocalcin, pulls that calcium into bone where it belongs. D3 and K2 are not optional companions — they're a functional pair.
The K2 form also matters. MK-4 has a half-life of just a few hours. MK-7, derived from fermented natto, stays in circulation for 72 hours — providing continuous activation of MGP and osteocalcin around the clock. One capsule per day covers you. We use 100mcg MK-7 paired with 5,000 IU D3 in an oil-based softgel, because fat-soluble vitamins absorb significantly better alongside dietary fat.
Key features
5,000 IU D3
Cholecalciferol — the form your skin makes from sunlight and the most bioavailable supplemental form. Enough to actually raise deficient levels to optimal range.
100mcg MK-7 K2
Long-chain menaquinone-7 from natto with a 72-hour half-life. Activates MGP and osteocalcin around the clock to direct calcium where it belongs.
Immune support
Vitamin D receptors are on virtually every immune cell. D3 modulates both innate and adaptive immune responses — it's one of the most studied immunity nutrients.
Mood & energy
Low D levels are consistently associated with fatigue and depressed mood, particularly in darker months. Restoring optimal D is often the first domino.
Oil-based softgel
Fat-soluble vitamins absorb significantly better in an oil matrix. No dry powder capsule will match the bioavailability of this format.
Third-party tested
Potency and purity verified per batch. Certificate of Analysis available on request. No synthetic fillers, no unnecessary additives.
Supplement facts
| Serving size | 1 softgel |
| Servings per container | 90 |
| Vitamin D3 (cholecalciferol) | 5,000 IU (125mcg) |
| Vitamin K2 (as MK-7 from natto) | 100mcg |
| Other ingredients | Extra virgin olive oil, softgel capsule (gelatin, glycerin, water) |
| Allergens | None. Gluten-free, soy-free, dairy-free. Contains gelatin (not vegan). |
| Suggested use | Take 1 softgel daily with your largest meal. Best taken in the morning or at lunch. |
| Best by | 24 months from manufacture. Store in a cool, dry place. |
| Country of manufacture | USA (NSF-certified, cGMP facility) |
How we compare
| Feature | Erivelle D3+K2 | D3-only brands | Low-dose D3 brands |
|---|---|---|---|
| K2 (MK-7) included | 100mcg ✔ | Not included ✘ | Not included ✘ |
| K2 form | MK-7 (72-hr half-life) ✔ | N/A | N/A |
| D3 dose | 5,000 IU ✔ | Often 1,000–2,000 IU ✘ | 400–1,000 IU ✘ |
| Oil-based softgel for absorption | ✔ | Often dry powder ✘ | Often dry powder ✘ |
| Third-party potency verified | ✔ | Varies ✘ | ✘ |
| 60-day guarantee | ✔ | ✘ | ✘ |
Questions about this product
Vitamin D3 increases calcium absorption significantly. Without K2, that extra calcium can deposit in arteries and soft tissue rather than bones. K2 (MK-7) activates osteocalcin and Matrix Gla Protein (MGP), which direct calcium into bones and away from arterial walls. D3 without K2 is an incomplete approach.
Research consistently shows that 1,000 IU is insufficient to raise deficient or insufficient vitamin D levels to the optimal 40–60 ng/mL range. Most adults require 3,000–5,000 IU daily to maintain optimal serum 25(OH)D. Toxicity occurs only at sustained doses of 10,000–40,000+ IU/day — well above this dose.
MK-7 (menaquinone-7), derived from natto. This is the long-chain form of K2 with a half-life of 72 hours, compared to MK-4 which clears in hours. MK-7 provides sustained activation of K2-dependent proteins throughout the day from a single daily dose.
Speak to your doctor first. Vitamin K can affect INR levels in people on warfarin. If you're on anticoagulants, your physician needs to be aware of any K2 supplementation so they can monitor your levels appropriately.
Take with your largest meal of the day, ideally one containing fat. Vitamin D is fat-soluble and absorbs significantly better when taken alongside dietary fat. Morning or lunch is ideal — some people report late-day D3 affects their sleep quality.
It's a good idea but not required. The vast majority of adults are deficient or insufficient (below 30 ng/mL). A 25-hydroxyvitamin D test is inexpensive and widely available. Testing before and 3 months after starting supplementation will confirm your response.
What customers say — 521 reviews · 4.8 avg
★★★★★May 1, 2025
My D levels went from 18 to 58 in 90 days
I had bloodwork done in January showing my 25-OH D at 18 ng/mL. My doctor recommended supplementation. I chose this because it had K2 included. Three months later, re-tested and I was at 58 ng/mL. Energy is genuinely better. I don't dread winter anymore. Easy five stars.
★★★★★April 5, 2025
Finally a D3 with K2 that makes sense
I've been taking D3 for a year without K2 and my naturopath mentioned the arterial calcification risk. Switched to this. The MK-7 form is important — most competitors use MK-4 which clears within hours. The 5,000 IU dose is what I needed. Been on it two months. No issues. Will keep buying.
★★★★★March 2, 2025
Immune season game changer
I used to get sick every winter without fail. Started this last October alongside the Omega-3 Clarity. Not once this winter. Could be coincidence, but my wife didn't get sick either and she also took it. Best $20 I spend monthly.