← The FormularyLong gameCalcium
Also known as Calcium carbonate / citrateThe mineral everyone knows and most people over-supplement.
Two things about calcium supplements deserve saying plainly. The first is that a meta-analysis of placebo-controlled trials found supplemental calcium associated with about a 15% higher cardiovascular risk in healthy postmenopausal women — not settled, still argued, and enough that 'food first' is the sensible default. The second is specific to this formula: a calcium supplement taken with a meal cut zinc absorption by about half in a controlled study, and PRIME contains 367 mg of calcium alongside 50 mg of zinc. That is a real interaction inside one capsule, and it is the kind of thing a dose ledger should let you notice.
The most abundant mineral in the body: 99% of it is structural, locked into bone and teeth, and the remaining 1% does the urgent work.
Blood calcium is held in a narrow band because the 1% that circulates runs muscle and nerve function. When intake falls short, the body takes what it needs from the skeleton — which is why a long-term shortfall shows up in bone rather than in symptoms. Absorption depends on vitamin D and drops as the single dose gets larger, so 500 mg twice beats 1,000 mg once.
Builds and maintains bone, and enables muscle contraction, nerve signalling and blood clotting.
Anyone not getting enough from food — dairy, tinned fish with bones, fortified drinks, greens. Most people eating a mixed diet are closer to sufficient than they assume.
With food, in doses of 500 mg or less at a time. Keep it away from zinc, iron and antibiotics by a couple of hours where you can.
Nothing perceptible. Calcium is structural insurance, judged in decades and measured on a scan.
Grade A as an essential nutrient. On supplements: a 2021 meta-analysis of double-blind placebo-controlled trials reported a 15% increase in cardiovascular disease risk with calcium supplementation in healthy postmenopausal women, while other meta-analyses found no association — the question is open. On interaction: calcium given with a meal reduced zinc absorption by about 50% in a controlled study, though calcium from ordinary food does not appear to.
Read the labelFood first — supplemental calcium has been associated with cardiovascular risk in some trials. Do not exceed 2,500 mg/day from everything combined. Calcium blocks zinc, iron and some antibiotics; space them apart. Speak to a doctor first if you have kidney stones or kidney disease.
Evidence grades describe how well an ingredient is studied — A well-supported, C emerging — not a promise of results. Educational, not medical advice. Doses are typical ranges; follow the label on the product.