Saccharomyces cerevisiae peptides have been investigated for their potential role in supporting the immune system and combating infections. These bioactive peptides, derived from the yeast Saccharomyces cerevisiae, exhibit antimicrobial properties in laboratory studies. Research demonstrates that certain peptides from this yeast can inhibit the growth of pathogenic bacteria and fungi, such as Escherichia coli, Staphylococcus aureus, and Candida albicans. The mechanisms are thought to involve disruption of microbial cell membranes and modulation of host immune responses, including stimulation of macrophages and enhancement of cytokine production.

While there is a growing body of in vitro and some in vivo evidence from animal studies supporting these effects, robust clinical trials in humans are limited. Some nutritional supplements use yeast-derived peptides or hydrolysates to support immune health, partly based on these laboratory findings. However, the translation of these results to meaningful infection prevention or treatment in humans is not yet well-established. Thus, the evidence base is considered preliminary, and the overall rating here is 2 out of 5, reflecting promising preclinical science but insufficient clinical validation for definitive therapeutic recommendations.