# item.guide
Side-by-Side Comparison Essential Vitamins & Minerals

Calcium (Elemental Ca) vs. Vitamin C (L-Ascorbic Acid)

Comparing 2 standards across 9 specifications. 9 key differences identified.

Comparing:
Calcium (Elemental Ca)
Vitamin C (L-Ascorbic Acid)

Calcium is the most abundant mineral in the human body (1.0–1.2 kg), with 99% sequestered in hydroxyapatite bone lattice and 1% tightly regulated at 8.5–10.5 mg/dL serum for cardiac contractility, nerve signaling, and blood coagulation. Adult RDA is 1,000–1,200 mg/day.

View full Calcium (Elemental Ca) spec sheet →

Vitamin C is a water-soluble electron donor and antioxidant essential for collagen proline/lysine hydroxylation, non-heme iron absorption, and immune phagocyte function. Adult RDA is 90mg (men) / 75mg (women), with a Tolerable Upper Limit of 2,000mg/day.

View full Vitamin C (L-Ascorbic Acid) spec sheet →

Specification Comparison Table

9 Parameters
Parameter / Spec
Nutrient Type
Essential Macromineral Water-Soluble Vitamin
Adult RDA / RDI
1,000 mg / day (Men 19–70, Women 19–50) / 1,200 mg (Women 51+, Men 71+) 90 mg (Men) / 75 mg (Women) (+35mg for smokers)
Tolerable Upper Limit (UL)
2,500 mg / day (Adults 19–50) / 2,000 mg / day (Adults 51+) (Avoid nephrolithiasis / vascular calcification) 2,000 mg / day (Avoid osmotic diarrhea)
Chemical Forms
Calcium Carbonate (40% elemental Ca / requires stomach acid), Calcium Citrate (21% elemental Ca / acid-independent), Hydroxyapatite L-Ascorbic Acid, Sodium Ascorbate, Calcium Ascorbate
Primary Biological Function
Hydroxyapatite bone/dental structure [Ca10(PO4)6(OH)2], Troponin-C actin-myosin muscle contraction, Factor IV blood clotting cascade, Exocytosis neurotransmitter release Prolyl/Lysyl Hydroxylase cofactor (Collagen), ROS scavenger, Carnitine synthesis
Deficiency Condition
Osteoporosis, Osteopenia, Rickets (children), Tetany (Trousseau's and Chvostek's signs of hypocalcemia) Scurvy (Collagen breakdown, capillary fragility, impaired wound healing)
Top Whole Food Sources
Parmigiano-Reggiano, Sharp Cheddar, Whole Milk, Sardines with bones, Kale, Tofu (Calcium-set), Fortified Plant Milk Red Bell Pepper, Strawberries, Citrus, Kiwi, Broccoli, Brussels Sprouts
Parathyroid Hormone (PTH) Homeostasis
Serum Ca2+ drop triggers PTH secretion, stimulating renal 1-alpha-hydroxylase to produce active Calcitriol (1,25-OH-D3) and osteoclast bone resorption
Thermolability
Highly heat- and oxygen-sensitive (degrades rapidly with prolonged boiling)