What it is
Arginine is a semi-essential amino acid carrying a guanidino group, with only the L-form occurring naturally in biology. In skincare it is one of the building blocks of skin and hair proteins and functions as a natural moisturizing factor that helps hydrate and condition skin and hair. Its positive charge makes it substantive to skin and hair, and it is also commonly used to neutralize acidic ingredients and balance a formula's pH.
Safety & warnings
Arginine is a naturally occurring amino acid that the body itself makes and that is one of the constituents of the skin's own moisturizing factors, so it is generally well tolerated in cosmetics. It is sometimes paired with acidic exfoliants, where it forms a complex that can produce a gentler, time-release acid effect and reduce the irritation usually associated with those acids.
Origin & sourcing
Commercial arginine is produced mainly by microbial fermentation, typically yielding on the order of 25–35 g per liter using glucose as a carbon source; traditional methods instead obtained it by hydrolyzing proteins such as gelatin.
History
Arginine was first isolated in 1886 by the German chemist Ernst Schulze and his assistant Ernst Steiger from yellow lupin seedlings; Schulze named it after the Greek word for silver because of the silver-white appearance of arginine nitrate crystals. Its structure was determined in 1897 and confirmed by synthesis around 1910.
Questions everyone asks
What does arginine do in skincare?
It is an amino acid that helps hydrate and condition skin and hair, and it is often used to adjust a product's pH by neutralizing acidic ingredients.
Is the arginine in cosmetics animal-derived?
Most commercial arginine is made by fermentation using glucose; historically it could be obtained by hydrolyzing proteins such as gelatin.
Can arginine make acids gentler?
Cosmetic references note arginine can form a complex with AHAs that gives a time-release effect and reduces the irritation usually linked to those acids.