The PureBulk Shiitake Mushroom Extract you linked is indeed standardized to ≥50% polysaccharides .
That means:
Each 1,000 mg serving = ~500 mg polysaccharides.
It’s a mushroom extract (Shiitake, not Astragalus), so the polysaccharides here are beta-glucans which is good for immune and antioxidant support, but not the same APS (Astragalus polysaccharides) that have kidney clinical data.
So it’s rich in polysaccharides, but it’s not the astragalus polysaccharides used for renal protection. It’s a different compound category with immune benefits.
Side-by-side with mine:
Both are “polysaccharides,” but different types:
- Astragalus polysaccharides (APS) = kidney RCT evidence.
- Mushroom beta-glucans = immune/liver support, no kidney trials.
- Zazzee = kidney-specific protection (evidence matches your goal).
- Shiitake = immune/liver support, not renal-focused.