Potassium Iodide
Potassium Iodide is a tier 1 form of Iodine, used in 3,668 on-market products and providing 76.4% elemental iodine by weight.
3,668
on-market products
tier 1
quality tier
76.4%
elemental fraction
Basis: KI, MW 166.00
Why this tier: Bioavailability 63.7-83.5% vs only 23.7-29.5% for kombu (kelp) in an RCT/crossover -- far more completely and predictably absorbed. "Potassium Iodine" is treated as a labeling variant of this form (not standard chemical nomenclature).
Source: Liu X et al. 2025, Food Sci Nutr 13(9):e70818