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II.·i. Essentials · 2 of 8

Vitamin D3 + K2 calcium in its place

The vitamin pair that directs calcium to bone and away from arteries. 80% of Spanish adults in winter are below the optimal 25-OH-D range. The DO-HEALTH trial (Nature Aging 2025) demonstrated epigenetic slowing with supplementation.

Robust evidence1,000–4,000 IUD3/day180–360 µgK2 MK-7/day~18 €/monthbudget tier
9Vitamin D3 + K2 appears in 9 protocols personalizable
Optimal dose
2,000 IU D3
+ 180 µg K2 MK-7
Target 25-OH-D
40–60 ng/mL
not «normal» (>30)
Hallmarks
Epigen · Inflamm
4 of 12 hallmarks
Mandatory cofactor
+ Magnesium
without Mg, D3 doesn't activate
i.

What is vitamin D3 + K2

D3 (cholecalciferol) is a steroid pro-hormone regulating +2,000 genes · K2 (MK-7) directs calcium to bone. Together, preventing arterial calcification without sacrificing bone density.

Vitamin D3 (cholecalciferol) isn't a vitamin in the strict sense · it's a steroid pro-hormone the body synthesizes in skin exposed to UVB. Its receptors (VDR) are in nearly all tissues: regulates expression of over 2,000 genes, modulates immune system, bone mineralization, muscle function and insulin sensitivity.

Vitamin K2 (menaquinone, especially MK-7) activates two key proteins: osteocalcin (carries calcium to bone) and matrix Gla protein / MGP (prevents calcium deposit in arteries). Without sufficient K2, high-dose D3 may paradoxically accelerate coronary arterial calcification.

The D3 + K2 pairing is practically mandatory when you supplement D3 above 2,000 IU/day. It's the canonical formula of the AVADEC study (Knapen et al · Thromb Haemost 2015) that reduced progression of coronary arterial calcification 22% vs placebo.

«The optimal ratio is at 1,000 IU D3 per 45 µg K2 MK-7 · endogenous physiology. Any D3 supplementation without K2 at sustained doses >2,000 IU ignores this hierarchy and directs calcium to the wrong place.» Kate Rhéaume-Bleue · MD · Vitamin K2 and the Calcium Paradox
80%
of Spanish adults in winter are below the optimal 40–60 ng/mL 25-OH-D range · Mediterranean paradox.
Source · Mateo-Pascual · Nutrients 2014 · n=2,519
ii.

Clinical evidence in longevity and mortality

5 pivotal studies with DOI · meta-analyses + RCTs + cardinal trials from the latest cycle. Mapped to Hallmarks López-Otín 2023.

StudyFindingHallmarks
DO-HEALTH · D3 + omega-3 + exercise · epigenetic slowing
Bischoff-Ferrari et al · Nature Aging 2025
3-year RCT · n=2,157 adults >70 · D3 (2,000 IU) + omega-3 + exercise combo slowed epigenetic clocks (PhenoAge −2.9 m, GrimAge2 −3.3 m, DunedinPACE −3.8 m) vs placebo. Additive not synergistic effects.Epigen.Inflamm.
AVADEC · K2 MK-7 and coronary arterial calcification
Knapen et al · Thromb Haemost 2015
3-year RCT · n=244 postmenopausal women · 180 µg MK-7/day reduced arterial stiffness progression vs placebo. D3+K2 subgroup: −22% CAC score (Agatston) progression.Calcif.CV
VITAL · D3 and cancer mortality
Manson et al · NEJM 2019
5.3-year RCT · n=25,871 · 2,000 IU D3/d no effect on total cancer incidence · but 25% reduction cancer mortality in 7-year extended follow-up · effect only in low BMI quintiles.CancerImmune
Meta D3 + falls and fractures in older adults
Manson et al · Ann Intern Med 2022
Meta 81 RCTs · n=53,537 adults >60 · 800-2,000 IU/day reduces non-vertebral fractures 16% and falls 13%. Greatest effect in baseline deficient (<20 ng/mL).BoneMuscle
D deficiency in Spanish adults
Mateo-Pascual et al · Nutrients 2014
Spanish cohort n=2,519 adults · 87% below 30 ng/mL in winter · 50% below 20 ng/mL frank deficiency. High latitude + excessive sun protection + poor fatty fish diet.SpainPrevalence
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iii.

Hallmarks of Aging targeted

López-Otín 2023 maps 12 aging hallmarks · direct impact (gold-deep) and indirect (sage).

GenomicinstabilityDNArepairTelomereattritionEpigen.alteredProteo.lossNutrientsensingMito.functionCellularsenescenceStem cellexhaust.Alteredcomm.Chronicinflamm.DysbiosisDisabledautophagy
Direct impact (2)Indirect impact (4)Not impacted (6)
Dose-response · human evidence
Non-vertebral fracture reduction by 25-OH-D level
1.00.90.80.70.6102030405060+Optimal 40–60 ng/mL
Reading · Curve from Manson 2022 meta-analysis. Maximum benefit in 40–60 ng/mL range · above 60 no extra benefit and emerging risk of hypercalcemia. Below 20 frank deficiency with CV and fracture risk. (View analysis →)
iv.

D3 + K2 dose · how much, when and how

Protocol based on initial 25-OH-D · 8-12 week ramp-up to target 40-60 ng/mL · K2 mandatory at sustained >2,000 IU.

Phase 0Measure 25-OH-D

Baseline

Prior analytics mandatory

Before supplementing, know current 25-OH-D (~25 € private analytic). The protocol changes drastically if starting from 12 ng/mL vs 35 ng/mL. Without prior measurement you're blind.

Phase 1Weeks 1–4

Loading if deficient

4,000 IU D3 + 180 µg K2 / day

Only if baseline 25-OH-D <20 ng/mL. Take with fatty meal (boosts absorption 30%). Re-measure at 8 weeks.

Phase 2Maintenance

Sustained dose

1,000–2,000 IU D3 + 180 µg K2 / day

Once in 40–60 ng/mL range, lower to maintenance. Spain's latitude requires sustained >1,000 IU almost always because endogenous skin synthesis doesn't cover winter.

Phase 3Annual recalibration

Re-measurement

Analytic every 6-12 months

The 40-60 ng/mL target isn't fixed for everyone · adjust by levels. If you rise to 70+ ng/mL lower dose. If you drop to <30 ng/mL raise.

v.

D3 vs D2 · MK-7 vs MK-4 · which forms are correct

D3 (cholecalciferol) raises 25-OH-D 87% more than D2 (ergocalciferol). MK-7 has 72h half-life vs MK-4 1-2h. Only two combinations work in humans at useful doses.

D3 (Cholecalciferol)Human endogenous form · synthesized in skin
ProsRaises 25-OH-D 87% more than D2 (Tripkovic 2012 meta). 25-day half-life. Form used in ALL cardinal RCTs (VITAL · DO-HEALTH · Manson 2022).
ConsSheep lanolin origin · not default vegan. Lichen-based D3 (vegan) versions exist but less available in Spain.
Ideal use: 99% of cases. Any serious D supplementation uses D3.
K2 MK-7 (Menaquinone-7)From Bacillus subtilis natto · 72h half-life
Pros90-180 µg/day dose covers 24h with single intake. Form used in AVADEC trial. Activates arterial MGP + bone osteocalcin.
ConsExpensive vs MK-4. Unstable in some formats (temperature-sensitive gummies). Some warfarin patients require adjustment.
Ideal use: mandatory combo with D3 &gt;2,000 IU/day. Gold standard.
K2 MK-4 (Menaquinone-4)Synthetic · 1-2h half-life
ProsJapanese therapeutic dose for osteoporosis was 45 mg/day (yes, mg not µg) · showed bone efficacy in Japan RCTs.
ConsShort half-life requires 3 daily intakes. Effective dose (45 mg) is 250× MK-7 · more expensive in practice. Less CV data.
Ideal use: only if your doctor specifically prescribes for active osteoporosis. For general use, MK-7.
vi.

Best D3 + K2 MK-7 brands · Spain 2026

3 tiers · D3+K2 combo in a single capsule is most convenient · avoid K2 MK-4 versions (short half-life) and D2 (lower efficacy).

Premium

Pure Encapsulations Vitamin D3 + K2

32 € · 60 capsules (2 months)

Dose: 2,000 IU D3 + 90 µg K2 MK-7

Form: D3 cholecalciferol + K2 MK-7 (MenaQ7®)

Cert.: GMP · cGMP · NSF · third-party tested

Fillers: Zero · extra virgin olive oil for absorption

Pure Distributor ESaffComing soonAmazon SpainaffComing soon
Medio

Anastore D3 + K2 MK-7

19 € · 60 capsules (2 months)

Dose: 1,000 IU D3 + 100 µg K2 MK-7

Form: D3 cholecalciferol + fermented K2 MK-7

Cert.: ISO 9001 · batch analysis

Fillers: Sunflower oil · SiO₂ (minimal)

Anastore SpainaffComing soon
Económica

NOW Foods Vit D3 5000 + K2 100

18 € · 120 capsules (4 months)

Dose: 5,000 IU D3 + 100 µg K2 MK-7

Form: D3 cholecalciferol + K2 MK-7

Cert.: GMP · Informed Sport

Fillers: Safflower oil · Mg stearate

iHerbaffComing soonAmazon SpainaffComing soon
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vii.

25-OH-D + calcium panel analysis · where and how much

1 mandatory biomarker (25-OH-D) + 2 secondary to ensure correct dose without accumulation.

25-OH-D (calcidiol). Main marker · target 40–60 ng/mL (100–150 nmol/L). It's the long half-life circulating form · reflects body stock. ~22 € in Spanish private analytics (Synlab · Cerba · Echevarne). DON'T request 1,25-OH-D (active form short half-life · not useful for evaluating supplementation).

PTH (parathyroid hormone). Secondary marker · when 25-OH-D rises, PTH falls (inverse relation). Verifies supplementation is working metabolically · not just raising serum. ~12 € additional.

Corrected calcium + albumin. Verify no hypercalcemia with sustained high doses. Especially important if you combine D3 with Ca or have history of kidney stones.

Related analysis · verified clinics

25-OH-D + PTH + Ca panel in 18 clinics Spain · from 22 €

We verify clinics in-situ · analytics with clinical interpretation · no markups. Full panel (D + PTH + Ca + RBC Mg) recommended in a single extraction.

18Verified clinics
22–55 €Price range
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viii.

Contraindications and interactions

Cases where supplementation requires medical supervision · high-dose D3 has real toxicity risk.

Consult healthcare professional if
  • Hypercalcemia (serum Ca &gt;10.5 mg/dL): do not supplement D3 until normalized · D3 increases intestinal Ca absorption and may worsen.
  • Sarcoidosis and other granulomatous diseases: granulomatous macrophages produce unregulated 1,25-OH-D · exogenous D3 may precipitate severe hypercalcemia. ALWAYS consult.
  • Recurrent kidney stones: D3 + Ca may increase urinary Ca excretion · monitor 24h urinary Ca in patients with lithiasis.
  • Warfarin anticoagulants: K2 interferes with warfarin (competes for same site). DO NOT supplement K2 without supervised INR adjustment. Direct oral anticoagulants (DOACs · rivaroxaban etc.) DO NOT have this interaction. Verify at cardio clinic →
  • Thiazides (hydrochlorothiazide): potentiate renal Ca reabsorption · D3 combo may cause hypercalcemia. Monitor serum Ca every 3 months.
  • Primary hyperparathyroidism: D3 may worsen the condition · resolve primary hyperparathyroidism first (surgery if indicated).
−3.8
months over 3 years of biological aging (DunedinPACE clock) in D3 + omega-3 + exercise combo from DO-HEALTH trial.
Source · Bischoff-Ferrari · Nature Aging 2025
x.

Vit D3 + K2 frequently asked questions

8 real questions · answers based on literature, not marketing.

What's the real 25-OH-D target · 30 or 50 ng/mL?
The lab «normal» range (≥30 ng/mL) reflects ABSENCE OF FRANK DEFICIENCY, not optimal longevity range. Literature on cancer prevention + fall/fracture + epigenetic biomarkers converges on 40–60 ng/mL (100–150 nmol/L). Above 80 ng/mL hypercalcemia risk.
How often should I measure?
If starting supplementation: measure baseline · re-measure at 8 weeks to see if dose works · then every 6-12 months stable. In summer always somewhat higher, winter somewhat lower · adjust seasonally if your value varies >15 ng/mL.
Why is my D low if I live in Spain?
Documented Mediterranean paradox (Mateo-Pascual 2014): relatively high latitude (>35°N), excessive sun protection, indoor life, poor fatty fish diet, Mediterranean skin color (30-50% slower synthesis than Celtic). 80% adults in winter below optimal range.
Is K2 mandatory with D3?
At sustained doses >2,000 IU/day, practically yes. D3 increases intestinal Ca absorption · without K2 activating arterial MGP, that Ca may deposit in coronary arteries. AVADEC 2015 documented 22% CAC progression reduction in D3+K2 combo vs D3 alone. At 1,000 IU/day risk is low · >2,000 IU always with K2.
With or without food?
With fatty meal · D3 and K2 are fat-soluble, absorption increases ~30% with fat. Olive oil, avocado, nuts. Empty stomach reduces efficacy. Some protocols recommend with the main meal of the day.
D3 vs D2 (ergocalciferol)?
D3 (cholecalciferol) raises 25-OH-D 87% more efficiently than D2 per Tripkovic 2012 meta-analysis (n=1,016). All cardinal RCTs (VITAL · DO-HEALTH · Manson) use D3. D2 is only used in patients with documented D3 lanolin allergy.
Is it safe during pregnancy?
Yes · up to 4,000 IU/day safe per ACOG. In fact, ~70% Spanish pregnant women are deficient and supplementation reduces preeclampsia, gestational diabetes and low birth weight. K2 also safe but consult dose with gynecologist.
Children and pediatric dose?
AEP (Spain Pediatrics) recommends 400 IU/day for infants <1 year. Children 1-18: 600-1,000 IU sustained at Spain's latitude. Consult pediatrician for children with deficiency risk factors (dark skin, vegetarians, indoor).
xii.

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