Certain medical conditions like autoimmune disease, stress, hormonal changes, malnutrition, low protein levels, and using harsh hair care products can lead to hair loss and low-density hair. While disease or hormonal changes-induced hair loss requires medical intervention, other causes of low-density hair can be addressed by consuming a healthy diet and applying the right hair care products (for instance, you can invest in the L’Oréal Professionnel Serioxyl Advanced serum that is known as a potent serum for hair density and to boost hair volume).