Healthy hair with a good amount of keratin
Photo: Andrii Borodai/Canva
Q: What exactly is keratin in our hair and what is it good for?
A: Keratin is a strong protein that plays a crucial role in forming the structure of hair, nails, and the outer skin layer in mammals, including humans. This protein provides toughness, elasticity, and protection. When it comes to hair, keratin is essential for determining its texture, strength, elasticity, and overall appearance, helping it resist damage and breakage.
Skin cells known as keratinocytes, found in the bottom layer of the skin, produce keratin. As these cells mature, they start producing keratin, which accumulates inside the cell. Eventually, the cell dies and becomes hardened, and the dead keratinocytes are pushed toward the outer skin layer, forming a protective barrier. Notably, keratin is hydrophobic, meaning it repels water.
In the context of hair, keratin production begins at the hair follicle's root, where keratinocytes continuously generate new keratin protein. As the hair shaft grows, these cells move up the follicle, adding layers of keratin to the shaft and forming the visible hair fibers.
Hair consists of three keratin layers: the cuticle, cortex, and medulla. The outermost layer, the cuticle, is composed of flattened, overlapping scales that create a protective barrier for the hair shaft. The cuticle also plays a role in retaining moisture, contributing to a smooth and glossy appearance. The medulla, the innermost layer, is present in specific hair types.
The cuticle layer with overlapping scales of a hair
Photo: Science Photo Library/Canva
The middle layer of hair, known as the cortex, is responsible for both the color and strength of our hair. This part is made up of long strands of keratin protein, tightly packed and woven together to create a complex three-dimensional structure. This structure is what gives our hair shaft its toughness and flexibility, helping it withstand the impact of styling, chemical treatments, UV rays, and other environmental factors.
Let's talk about Keratin and Hair Color:
Our hair color is determined by a pigment called melanin, produced by cells called melanocytes. These cells create and transfer melanin to the nearby keratinocytes. As our hair grows, the melanin becomes part of the cortex.
There are two types of melanin crucial for hair color: eumelanin and pheomelanin. Eumelanin is responsible for darker hair shades like brown to black, while pheomelanin produces lighter, reddish-yellow hues. The balance between these two in the cortex determines our hair color.
However, it's not just about the amount of melanin; distribution matters too. Hair filled densely with melanin appears darker than less densely filled hair. As we age, our hair follicles' melanocytes become less active and produce less pigment, leading to gray or white hair.
Microscopic view of a gray hair root and follicle
Photo: Sergii Trofymchuk/Getty Images via Canva
Understanding Keratin's Role:
The makeup and arrangement of keratin in our hair can differ based on factors like genetics, age, diet, and surroundings. For instance, African-American hair usually has tightly packed and more complex keratin, giving it a unique texture and curl. Changes in keratin due to aging or illness can also alter hair texture and appearance.
Beyond structure, keratin is crucial for healthy hair. Frequent heat styling, like blow-drying and using flat irons, can break down keratin bonds, causing damage, breakage, and split ends. Proper hair care, including the use of products designed to protect and strengthen keratin fibers, can prevent this.
Keratin Shortage:
Insufficient keratin can lead to dry, brittle hair prone to breakage. A deficiency weakens the hair shaft, making it struggle with regular brushing, combing, and styling. This results in increased breakage and split ends.
Moreover, a lack of keratin can bring about dryness and lackluster hair. When there's not enough keratin, the hair struggles to retain moisture, leading to dry, frizzy, and unruly strands. This is particularly noticeable in people with curly hair, which tends to be naturally more prone to dryness.
Several factors, such as genetics, age, stress, illness, and exposure to environmental toxins, can contribute to keratin deficiency. Additionally, a diet lacking essential vitamins and minerals may lead to insufficient keratin.
Keratin Treatments:
Keratin-based hair treatments are gaining popularity for repairing and strengthening damaged hair. These treatments typically involve applying a keratin-based solution to the hair, sealed in with heat. Keratin in hair care products can come from various sources, including both animals and plants. The most commonly used source is animal-based, specifically from sheep wool and feathers.
Sheep as a source of Keratin for human hair
Photo: Eyewave/Canva
Sheep wool and feathers play a key role in many hair care products like shampoos, conditioners, and treatments. The keratin found in sheep wool gets broken down into a soluble form that the hair easily absorbs. We often call this kind of keratin "soluble keratin," and it's believed to enhance the overall health and appearance of our hair.
Similar to sheep wool, feathers are rich in keratin, and when broken down, they become a soluble form that the hair readily absorbs. This type of keratin is frequently used in hair treatments to boost strength, elasticity, and overall hair health.
Beyond animals, we can also get keratin from plants like soy, corn, and wheat. These plant-based sources, known as "plant-based peptides," are thought to offer similar benefits to animal-derived keratin. However, some experts debate whether plant-based keratin is as effective as the animal-derived kind, suggesting that the structure of plant-based keratin might not closely match that of human hair.
When selecting a hair care product with keratin, it's crucial to opt for those containing high-quality, hydrolyzed keratin. This type of keratin is believed to be the most effective in promoting hair health.
See also:
How to analyze your hair
What is hair made of and how does it grow?