Youtheory's spore-based probiotic uses Bacillus strains naturally encased in a protective shell, letting them survive stomach acid and reach the gut alive in far higher numbers than many standard probiotics. This also makes the formula shelf-stable at room temperature. A solid option for anyone who wants reliable gut and immune support without worrying about refrigeration or acid sensitivity. As with any probiotic, those who are immunocompromised or on medication should check with their doctor first.