About MOS
Short-chain carbohydrates derived primarily from yeast (Saccharomyces cerevisiae) cell walls. Act as a prebiotic and pathogen-binding agent by mimicking gut epithelial receptors. Extensively studied in animal nutrition (poultry, swine, aquaculture) with hundreds of studies, but human clinical evidence is extremely limited — essentially one proper RCT (PeerJ 2021, n=60, 3–5 g/day for 21 days) showing prebiotic effects. No human meta-analyses or systematic reviews exist. Derived from a GRAS organism (baker's yeast) with no reported safety concerns in limited human testing. Should not be confused with D-mannose (a different compound used for UTI prevention).
What MOS supports
- Prebiotic — may support beneficial gut bacteria
- Pathogen-binding properties shown in animal studies
How much MOS to take
The RDA prevents deficiency. The effective range is what clinical trials used to actually move the outcome.
Effective
3000–5000
mg
3–5 g/day used in the one completed human RCT (copra meal MOS, PeerJ 2021, n=60). No standardized human dose established.
Clinical evidence
Limited clinical evidence. Extensive animal evidence but essentially 1 human RCT (PeerJ 2021, n=60); no human meta-analyses
NIH Fact Sheet