Keratin is a fibrous protein that serves as a structural building block in the human body. It provides strength and integrity to various tissues, forming a protective barrier against environmental stressors and is a fundamental component of the body’s protective outer layers.
How Your Body Makes Keratin
The human body naturally produces keratin through specialized cells called keratinocytes. These cells are found in the epidermis, the outermost layer of the skin. As keratinocytes mature, they migrate towards the skin’s surface and fill with keratin proteins, forming a durable, protective layer. This process of keratinization is continuous, with old, keratin-filled cells constantly shed and replaced by new ones.
Keratin is also the primary structural protein in hair and nails. Hair follicles produce keratinocytes that synthesize the keratin forming hair strands. Similarly, the nail matrix, located at the base of each nail, generates keratinocytes responsible for nail plate formation. The body continuously synthesizes keratin, maintaining and repairing these protective structures.
Nutrients That Support Keratin
While the body naturally produces keratin, its synthesis depends on specific nutrients obtained through diet. Adequate protein intake is important, as keratin is a protein composed of amino acids like cysteine and methionine. These sulfur-containing amino acids contribute to the strong disulfide bonds that give keratin its rigidity and strength. Without sufficient protein, the body may struggle to produce enough keratin.
Biotin, also known as vitamin B7, supports keratin production, though its exact mechanism is still being researched. It plays a role in metabolic processes that contribute to healthy skin, hair, and nails. Zinc is also involved in protein synthesis and cell division, processes important for the continuous production of keratinocytes.
Vitamin C is important for collagen production, another structural protein that works with keratin to maintain skin integrity. Iron is similarly important, as iron deficiency can impact hair and nail health, indirectly affecting keratin structures. A balanced diet rich in these nutrients provides the necessary building blocks and cofactors for the body’s keratin synthesis.
Keratin in Topical Products
Beyond the body’s internal production, keratin is a common ingredient in many topical cosmetic products for hair and skin. Shampoos, conditioners, hair masks, and serums often contain hydrolyzed keratin, which is keratin protein broken down into smaller peptides. This process allows the keratin fragments to penetrate the outer layers of the hair shaft or skin more effectively.
When applied to hair, hydrolyzed keratin can temporarily fill gaps in the hair cuticle, leading to a smoother surface, reduced frizz, and improved shine. It may also enhance the hair’s strength and elasticity, making it less prone to breakage. For skin, topical keratin products can form a protective film, contributing to a smoother texture and improving hydration by reducing moisture loss. These applications provide external benefits, as the applied keratin does not integrate into the body’s naturally synthesized structures.
Oral Keratin Supplements
Oral keratin supplements are available, typically in capsule or powder form, often containing hydrolyzed keratin derived from animal sources like sheep’s wool or feathers. These supplements are marketed with claims of promoting healthier hair growth, strengthening nails, and improving skin elasticity and hydration. The premise is that ingesting hydrolyzed keratin allows the body to absorb amino acids and peptides for internal keratin synthesis.
Some supplements combine keratin with other vitamins and minerals, such as biotin, zinc, and B vitamins, to support hair, skin, and nail health. While anecdotal reports and some preliminary studies suggest benefits, scientific evidence supporting the efficacy of oral keratin supplements for improvements in hair, nail, or skin health is still developing. The body’s digestive system breaks down proteins into their constituent amino acids, which become available for general protein synthesis, including keratin production. Therefore, direct incorporation of ingested keratin into specific structures like hair or nails is not straightforward.