Protein is scientifically validated as essential for supporting the hair body system. Hair is predominantly composed of a protein called keratin, which is synthesized in hair follicles. Dietary protein provides the amino acids necessary for the creation of keratin and the maintenance of healthy hair growth. Numerous studies have demonstrated that inadequate protein intake can lead to hair thinning, shedding, and, in severe cases, hair loss (telogen effluvium). Clinical evidence supports that restoring adequate protein intake can help reverse such hair changes if caused by deficiency. Furthermore, certain amino acids, such as cysteine and methionine, play particularly important roles in keratin structure and hair strength.

The importance of protein for hair health is recognized by organizations such as the American Academy of Dermatology, which recommends a balanced diet rich in protein to support optimal hair growth. While protein supplementation does not necessarily lead to increased hair growth in individuals with adequate dietary intake, it is vital for those at risk of deficiency, such as individuals with restrictive diets, eating disorders, or certain medical conditions. Thus, the use of protein to support the hair body system is strongly backed by scientific evidence, earning the highest possible rating for evidence.