Vitamin D3 + K2 dosage

Protocol

1. 1

   Measure the dose

   Typical Vitamin D3 + K2 dose is 0.05 mg (1000 to 4000 IU/day vitamin D3 (titrate to serum 25(OH)D 30 to 50 ng/mL); 90 to 180 mcg/day K2 as MK-7). Use a weight-based calculator for individual adjustments.

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2. 2

   Set the frequency

   Administer daily with a fat-containing meal. Half-life of 360 hours anchors the dosing interval.

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3. 3

   Cycle if needed

   No cycling; continuous daily use is standard

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4. 4

   Monitor for side effects

   Watch for: GI upset at high doses; headache (rare); hypercalcemia (only at sustained very high D3 doses). Stop or reduce dose if tolerability breaks down.

Why this dose

D3 converts to calcidiol then calcitriol, activating the vitamin D receptor (VDR) to increase intestinal calcium absorption and modulate immune and bone gene transcription. K2 carboxylates osteocalcin and matrix Gla protein, directing calcium toward bone and inhibiting vascular calcification.

The typical dose (0.05 mg) reflects 1000 to 4000 IU/day vitamin D3 (titrate to serum 25(OH)D 30 to 50 ng/mL); 90 to 180 mcg/day K2 as MK-7. Individual response varies with body weight, baseline status, concurrent training, and concurrent medications, so the labeled range is the starting point rather than the prescription.

How to administer

Vitamin D3 + K2 is administered via the oral route. Oral dosing is straightforward: take with water, with or without food unless specifically noted.

Onset of action runs around 24 hours after administration. Peak effect lands near 1 weeks post-dose. Plan the administration window so that peak effect lines up with whatever outcome you are dosing for, whether that is training, sleep, or symptom coverage.

Half-life note: 25(OH)D plasma half-life ~2 to 3 weeks; tissue stores extend functional half-life to ~2 months. MK-7 plasma half-life ~72 hours.

Cycling and tolerance

No cycling; continuous daily use is standard

Effects to expect at typical dose

• Reduces non-vertebral fractures 10-20% in older adults at 800 IU/day or above when combined with calcium
• VITAL trial showed neutral results on primary CV and cancer endpoints at 2000 IU/day over 5 years
• Vitamin D supplementation reduces respiratory infection incidence ~10-20% in deficient populations
• K2 MK-7 has 72-hour plasma half-life vs 1-2 hours for MK-4; once-daily dosing is sufficient
• Synergy hypothesis is largely preclinical; dedicated combination RCTs are limited
• Daily dosing outperforms bolus dosing for immune and infection outcomes

Side effects and interactions

Common side effects

• GI upset at high doses
• headache (rare)
• hypercalcemia (only at sustained very high D3 doses)

Notable interactions

• warfarin (moderate): K2 component can affect anticoagulation; maintain stable intake and inform anticoagulation clinic
• thiazide diuretics (moderate): additive calcium retention; hypercalcemia risk with high-dose D3
• digoxin and calcium channel blockers (moderate): additive effects from D3-induced hypercalcemia
• glucocorticoids (moderate): reduced vitamin D efficacy and bone effects
• cholestyramine and orlistat (moderate): bind fat-soluble vitamins; separate dosing by 2 to 4 hours

Lists above cover commonly reported and well-characterized items. They are not exhaustive: review the full Vitamin D3 + K2 profile and discuss with a clinician familiar with your medication list before starting, particularly if you are on prescription therapy or have a chronic condition.

Regulatory snapshot

WADA status

allowed

DEA / Rx

Not scheduled

Pregnancy

Recommended at standard doses for fetal bone development; consult clinician at higher doses

Legal status

Dietary supplement (global)

Do not use if

• hypercalcemia
• sarcoidosis
• active hyperparathyroidism
• warfarin therapy (K2 component requires stable intake)

Related research