Lion’s mane (Hericium erinaceus) polysaccharides significantly enhanced probiotic performance in lab models, increasing beneficial bacterial growth and boosting adhesion of Lactiplantibacillus plantarum by up to 30% at just 50 μg/mL. The extracts also showed antioxidant activity and preserved over 70% probiotic survival after 90 days of freezing at −20°C. In practical terms, lion’s mane may help probiotics grow stronger, stick better to the gut lining, and survive storage and digestion.