Supplements. In addition to dietary changes, taking supplemental vitamins or enzymes can help slow down hair loss. Vitamin A is considered the building block of all cells. As the fastest growing tissue in the body, hair requires Vitamin A to grow. The scalp also needs Vitamin A to make sebum, a waxy, oily substance that keeps scalps moisturized and reduces breakage due to shedding. Vitamin B is another key vitamin for hair health. Biotin and Panthenol, both forms of Vitamin B, stimulate blood production that activates hair follicles. Vitamin D has been shown to help create new hair follicles. Because most people don’t get enough sun exposure, taking a Vitamin D supplement could reverse hair loss in some patients.