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

Iodine (Elemental I) vs. Vitamin B6 (Pyridoxal 5'-Phosphate / PLP)

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

Comparing:
Iodine (Elemental I)
Vitamin B6 (Pyridoxal 5'-Phosphate / PLP)

Iodine is an essential halogen trace element required exclusively as an essential structural component of thyroid hormones thyroxine (T4) and triiodothyronine (T3), regulating metabolic rate, cellular respiration, and fetal neurodevelopment. Adult RDA is 150 µg, with an Upper Limit of 1,100 µg/day.

View full Iodine (Elemental I) 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 Trace Halogen Element Water-Soluble Pyridine Vitamin
Adult RDA / RDI
150 µg / day (220 µg pregnancy / 290 µg lactation) 1.3 mg / day (Adults 19–50) / 1.7 mg (Men 51+) / 1.5 mg (Women 51+)
Tolerable Upper Limit (UL)
1,100 µg / day (Avoid Wolff-Chaikoff thyroid autoregulatory shutdown) 100 mg / day (US FDA/NIH) / 12 mg / day (EFSA, revised down from 25mg in 2023) (Avoid sensory peripheral neuropathy)
Chemical Forms
Iodide (I- / Potassium Iodide KI, Potassium Iodate KIO3 in iodized salt), Molecular Iodine Pyridoxal 5'-Phosphate (PLP, active coenzyme), Pyridoxine HCl, Pyridoxamine
Primary Biological Function
Constituent of Thyroxine (T4, 4 iodine atoms / 65% by weight) and Triiodothyronine (T3, 3 iodine atoms / 59% by weight) Transamination / deamination of amino acids, Serotonin / Dopamine / GABA synthesis from amino acids, Glycogen phosphorylase cofactor, Heme synthesis
Deficiency Condition
Endemic Goiter (Compensatory thyroid enlargement), Congenital Hypothyroidism / Cretinism (Permanent neurodevelopmental impairment), Maternal miscarriages Microcytic sideroblastic anemia, Seborrheic dermatitis, Cheilosis, Peripheral neuropathy, Convulsions
Top Whole Food Sources
Kombu Kelp, Nori Seaweed, Atlantic Cod, Eastern Oysters, Iodized Table Salt, Greek Yogurt, Dairy Milk, Eggs Chickpeas, Wild Salmon, Yellowfin Tuna, Beef Liver, Chicken Breast, Russet Potatoes, Bananas
Iodized Salt Public Health Impact
Universal salt iodization (45–75 mg KI / kg salt) is hailed as one of the greatest global public health achievements, eradicating cretinism worldwide
Neurotoxicity Threshold
Chronic megadosing of Pyridoxine HCl (>200–500mg/day) causes reversible sensory neuropathy due to competitive inhibition of tissue PLP