Can protein smoothies cause hair loss? Half of Europeans and Americans use supplements, according to recent statistics. By 2017, analysts estimate that the health supplement industry will grow to a staggering $36.1 billion. Protein shakes are among the most popular supplements available, often viewed as a relatively transparent and safe option for managing weight, muscle mass, and even sugar cravings. Now, fitness enthusiasts are concerned after a correlation between protein shakes and hair loss is sweeping the Internet.