Some sources recommend using shampoos with ingredients like minoxidil to stimulate hair growth. However, there is no strong evidence that this will help hair loss after bariatric surgery. Telogen effluvium associated with bariatric surgery is usually a short-term condition. Using topical treatments like minoxidil is unlikely to help because it can take up to a year to start seeing results. Utilizing a volumizing shampoo or hair product or avoiding products that would weigh your hair down may help camouflage some of the hair thinning in the meantime. Your hairdresser can help you find products best suited to your hair type.