Trying to grow out your hair? Length isn’t the only thing you need to consider when growing out your hair — density is equally important. Lush hair starts with healthy hair follicles — and hair serums can help you achieve that. But not all hair serums are created equal. The phyto-actives found in our GRO Hair Serum visibly increases hair density, strengthens hair follicles and encourages thicker, fuller-looking hair.