Nutrafol Hairbiotic MD is a professional-strength booster that targets the gut microbiome as a root cause of thinning hair. Physician formulated with specific strains to help diversify the microbiome to address gut-related pathways that are impacted in hair health. Gut health is one of the primary systems that pertains to hair health. Gut health disruptors can include stress, antibiotic usage, poor diet, aging, and lack of exercise.