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

Calcium (Elemental Ca) vs. Vitamin B6 (Pyridoxal 5'-Phosphate / PLP)

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

Comparing:
Calcium (Elemental Ca)
Vitamin B6 (Pyridoxal 5'-Phosphate / PLP)

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 B6 is a water-soluble pyridine vitamin acting via its active coenzyme Pyridoxal 5'-Phosphate (PLP) in over 140 amino acid decarboxylation, transamination, and neurotransmitter synthesis reactions. Adult RDA is 1.3–1.7 mg, with a Tolerable Upper Limit of 100 mg/day.

View full Vitamin B6 (Pyridoxal 5'-Phosphate / PLP) spec sheet →

Specification Comparison Table

9 Parameters
Parameter / Spec
Nutrient Type
Essential Macromineral Water-Soluble Pyridine Vitamin
Adult RDA / RDI
1,000 mg / day (Men 19–70, Women 19–50) / 1,200 mg (Women 51+, Men 71+) 1.3 mg / day (Adults 19–50) / 1.7 mg (Men 51+) / 1.5 mg (Women 51+)
Tolerable Upper Limit (UL)
2,500 mg / day (Adults 19–50) / 2,000 mg / day (Adults 51+) (Avoid nephrolithiasis / vascular calcification) 100 mg / day (US FDA/NIH) / 12 mg / day (EFSA, revised down from 25mg in 2023) (Avoid sensory peripheral neuropathy)
Chemical Forms
Calcium Carbonate (40% elemental Ca / requires stomach acid), Calcium Citrate (21% elemental Ca / acid-independent), Hydroxyapatite Pyridoxal 5'-Phosphate (PLP, active coenzyme), Pyridoxine HCl, Pyridoxamine
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 Transamination / deamination of amino acids, Serotonin / Dopamine / GABA synthesis from amino acids, Glycogen phosphorylase cofactor, Heme synthesis
Deficiency Condition
Osteoporosis, Osteopenia, Rickets (children), Tetany (Trousseau's and Chvostek's signs of hypocalcemia) Microcytic sideroblastic anemia, Seborrheic dermatitis, Cheilosis, Peripheral neuropathy, Convulsions
Top Whole Food Sources
Parmigiano-Reggiano, Sharp Cheddar, Whole Milk, Sardines with bones, Kale, Tofu (Calcium-set), Fortified Plant Milk Chickpeas, Wild Salmon, Yellowfin Tuna, Beef Liver, Chicken Breast, Russet Potatoes, Bananas
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
Neurotoxicity Threshold
Chronic megadosing of Pyridoxine HCl (>200–500mg/day) causes reversible sensory neuropathy due to competitive inhibition of tissue PLP