OsteoBase by Ortho Molecular Products

If your Vitamin D, 25-Hydroxy is low-normal and your diet is light on dairy or calcium-rich foods, a combined calcium magnesium vitamin D3 K2 stack is an easy maintenance play. It fits postmenopausal women, adults over 40 with low sun exposure, and people on acid-suppressing drugs who struggle with mineral absorption. The 300 mg calcium per serving is a complement to food intake, not a high-dose repletion. Pair it with weight-bearing exercise and track with DEXA and, for vitamin D, retest in 8–12 weeks.

This formula blends calcium hydroxyapatite (the same calcium-phosphate mineral your skeleton uses) with dicalcium malate, which is gentler on the gut than carbonate. Vitamin D3 increases calcium absorption and helps restrain parathyroid hormone (the signal that pulls calcium out of bone). Vitamin K2 as MK-7 activates osteocalcin (the protein that locks calcium into bone) and matrix Gla-protein (a protein that helps keep calcium from depositing in arteries). Magnesium is a cofactor for vitamin D activation and contributes directly to bone matrix.

Take three capsules daily with meals, ideally split across two meals to improve absorption and reduce constipation risk. Calcium and magnesium compete with certain drugs and nutrients, so separate by at least 2–4 hours from iron, levothyroxine (thyroid medication), and tetracycline or fluoroquinolone antibiotics. Consistency matters more than time of day. Recheck Vitamin D, 25-Hydroxy in 8–12 weeks; bone density changes are measured by DEXA over 12–24 months.

Skip or get clinician guidance if you use warfarin (vitamin K2 opposes its effect), have a history of high calcium, sarcoidosis, or advanced kidney disease. Thiazide diuretics can raise blood calcium. For recurrent kidney stones, take calcium with meals and avoid excess; discuss with your nephrologist. This hydroxyapatite is bovine-derived—not vegan. If you already hit your calcium target from food, you may prioritize vitamin D3 and magnesium alone.