We recommend taking all 4 capsules for best results. Nutrafol's physician-formulated hair growth formulas each contain over 20 vitamins, minerals and natural ingredients with standardized potency at their effective serving sizes to target root causes of hair thinning and have been clinically tested to improve hair growth when taking 4 pills daily. As always, if you are on prescription medications or have specific concerns, we recommend talking to your healthcare provider before starting any new dietary supplement, including Nutrafol products.