Fine hair can be directly due to your DNA, which genetically determines its diameter, making it smaller than average, around 50 to 60 micrometers instead of the 70 micrometers of so-called "normal" hair. While this diameter makes them more fragile, it doesn't prevent them from having a beautiful mass. The key is to protect it! What's more, in the course of our lives, we can all find ourselves with thinning hair. An unsuitable routine, over-aggressive treatments, excessive heat, chemical coloring, nutrient deficiencies or hormonal variations can make hair even thinner, resulting in a lack of volume.