Synopsis

Source of validity: Scientific
Rating (out of 5): 3

Amino acids are scientifically recognized as fundamental building blocks for the synthesis of proteins, including keratin, the primary structural component of hair. The hair growth cycle and hair shaft integrity both depend on adequate protein and amino acid supply. Several studies have demonstrated that deficiencies in certain amino acids, such as cysteine, methionine, and lysine, can negatively impact hair growth and quality. Supplementation with amino acids, particularly those high in sulfur like cysteine and methionine, is often included in formulations aimed at supporting hair health. Clinical evidence supports that amino acid supplementation may benefit individuals with hair loss related to nutritional deficiencies or increased physiological demand. However, the evidence supporting amino acid supplementation for hair health in otherwise healthy individuals with adequate dietary protein is moderate. Most people consuming a balanced diet receive sufficient amino acids for normal hair growth, and excess supplementation does not necessarily translate to improved hair quality or accelerated growth. Some small studies and reviews suggest potential benefits for specific populations, such as those with telogen effluvium or hair shedding due to restricted diets. Overall, while the biological rationale is strong and there is some clinical evidence, the strength of evidence for broad use in the general population is not robust, justifying a moderate rating.

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Douglas Laboratories Free Form Amino