Zinc Sulfate
Zinc Sulfate is a tier 2 form of Zinc, used in 434 on-market products and providing 22.7% elemental zinc by weight.
434
on-market products
tier 2
quality tier
22.7%
elemental fraction
Basis: ZnSO4 x 7H2O, heptahydrate (classic OTC form; a monohydrate at 0.364 also exists commercially -- check specific labels)
Why this tier: WHO/UNICEF-recommended form for diarrhea-management zinc dosing and the classic reference standard in absorption literature, but no specific head-to-head human isotope-absorption percentage vs citrate/gluconate/picolinate was verified.
Source: uncertain -- needs review (WHO/UNICEF clinical-use basis, not a specific bioavailability study)