Our thickening shampoo contains niacinamide as well as other ingredients that are popular for their hair growth benefits. Rosemary oil, panthenol, and aloe barbadensis leaf juice have all been shown to help with hair retention. Thickening shampoo contains niacinamide as well as other ingredients that are popular in hair loss shampoos for their hair growth benefits. Rosemary oil has been commonly used to promote hair growth similar to minoxidil.