Arginine HCL improves blood circulation and therefore stimulates the scalp and encourages hair growth. Combined with other protein-derived ingredients, it will also help to coat and temporarily repair split ends.
Arginine HCL is the hydrochloride (HCL) salt of L-arginine, a semi-essential amino acid that is naturally found in the human body, red meat, poultry, fish and dairy products - but a cruelty-free version can also be synthesised in a laboratory.
In the body, L-arginine is involved in many metabolic processes and plays an important role in immune function, cell division and wound healing. It converts into a chemical called nitric oxide, which causes the blood vessels to open wider and improves blood flow. For this reason, it also helps to promote hair growth: when the blood supply to the hair root improves, hair is more likely to grow long and strong.
Protein-derived substances like arginine HCL, hydrolysed wheat gluten and leucine are used to temporarily protect and repair each hair strand. They are attracted to keratin (the protein in the hair) and thus will cover the strand and stick to it that the split ends come back together again.