Keratin, a fibrous, flexible and strong protein, is the main building block of hair, skin and nails. Keratin is often derived from natural sources such as sheep's wool, bird feathers and animal hooves for use as a strengthening agent in beauty products. Keratin extraction through hydrolysis, a process that causes a chemical reaction using water, heat and acid, often yields the keratin for such purposes. Functional keratin requires an extraction method different from hydrolized keratin.
A process known as enzymatic or acidic hydrolization yields protein hydrolysates. Keratin is a structural protein rich in essential amino acids, such as L-cysteine, making it a valuable ingredient for skin and hair care. A great demand exists for methods of extraction that preserve keratin's valuable components, according to a Russian study published in "Applied Biochemistry and Microbiology." Researchers note the difficulty of extracting quality hydrolosates from keratin through the use of chemical agents and enzymes due to the protein's inherently strong and highly organized covalent bonds.
According to the Russian study, hydrothermal, acid, alkaline and enzymatic hydrolysis are the main methods of breaking down keratin-containing stock. Enzymatic is the most successful in preserving amino acids because it's a relatively gentle process, and it's safer for the environment than other methods. Controlled enzymatic hydrolysis of wool yields keratin lysate in liquid and powder forms for cosmetic use. Some believe the melting and heating of keratin-containing stock causes chemical changes that alter its efficacy for skin and hair, rendering it useless.
A New Zealand-based method of deriving keratin from wool is claimed to be less degrading than traditional hydrolyzation methods. This "bioavailable" form known as functional keratin is said to preserve keratin in its natural form, allowing it to work better with skin's chemistry when applied. It's often referred to as "liquid skin" for its ability to match and improve skin's own elasticity and generate new skin cell production.
Some companies have used the functional keratin method to produce their lines of keratin products, such as Liquid Keratin, a line of hair-straightening products.