Vitamin D is required for calcium absorption in the gut. Without adequate D3, dietary and supplemental calcium passes through largely unabsorbed. D3 is the gatekeeper that determines how much calcium actually enters the bloodstream.
This pair requires two separate supplements. Both are needed for the synergy to work.
Calcium for bone density support. Split into two doses since the body can only absorb about 500 mg at once. Calcium citrate can be taken any time; calcium carbonate requires stomach acid.
View on Amazon →Vitamin D3 (cholecalciferol) upregulates the calcium transport proteins in your gut that enable active absorption. Without it, calcium absorption falls below 15%. Fat-soluble, so take with a fatty meal.
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Coming soonHow to take this pair: Split calcium into two 500 mg doses with meals. Take 1,000-4,000 IU vitamin D3 with your fattiest meal. Never take calcium and iron within 2 hours as they compete for absorption. Consider adding vitamin K2 (MK-7) to direct calcium into bone rather than arteries. Consistent long-term supplementation matters far more than any individual dose.
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