Our hair is a vital aspect of presenting ourselves to the world. Having healthy hair is essential for both aesthetic and practical reasons. It is one of the few physical characteristics you can alter to suit the dictates of culture and fashion.
Healthy hair looks and feels good. It’s shiny and smooth, and it’s more resistant to damage and breakage. But is there a more precise way to define it? What exactly makes healthy hair healthy? And what are the factors that have an impact on the health of our hair?
These are the questions we aim to explore in this article.
Table of content
What are the key elements that promote healthy hair?
There are 3 main elements that impact the health of our hair. Its chemical composition, its structure, and its physical and mechanical properties. We’ll take a closer look at each one below.
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The main components of hair
In a chemical sense, about 80% of human hair is made of a protein called keratin, a vital component of not only hair but also skin and nails. Keratin is insoluble in water - this is what makes hair waterproof and helps to protect it from damage. It is rich in a type of sulfur amino acid called cysteine that forms bridges between molecules - this gives hair its rigidity and strength.
If you'd like to learn more about the importance of cysteine and other amino acids in keeping hair healthy, you can explore more here.
The structure of hair
Each thread of hair is organised in a 3-layer structure:
- The first is the pith, also known as the medulla, which is the central part of the shaft. A soft and greasy substance having amorphous nature makes up the pith. Its function isn’t completely clear and it has little effect on most cosmetic treatments of hair.
- The layer around the medulla is called the cortex, which makes up 75% of the hair’s structure. It contains long chains of keratin that give the hair its elasticity, flexibility, and resistance.
- The cuticle is the protective layer that covers the hair thread, consisting of scale-like cells that overlap each other. This is the part most affected by cosmetic treatments and gives healthy hair its smooth appearance and lustrous shine.
Physical and mechanical properties of hair
Whether your hair is healthy is affected largely by its physical and mechanical properties, such as resistance to stretching, shine, and elasticity. For example, hair that has a shiny appearance and a high resistance to stretching is considered healthy, while hair that’s matt and breaks easily when stretched is considered unhealthy.
Below, we’ll take a look at some of the most important properties of hair.
Hair elasticity
Hair fiber has an elastic characteristic. When dry, the hair thread may stretch up to 20-30% of its length without damage. When wet, this can go up to 50% - one of the reasons hair is more prone to damage when wet. Stretching it to 80% can cause hair to break. Physical and chemical treatments, such as ammonia or the use of heat tools can negatively affect hair’s elasticity.
Resistance to stretching
Hair’s resistance to stretching contributes to its resistance to breakage. How well hair tolerates stretching depends on the diameter of the thread and the condition of the cortex and is negatively affected by chemical treatments.
Friction
Due to its scale shape, the cuticle has high friction. The constant rubbing of one hair thread to another can wear down and damage the cuticle. Factors such as humidity, permanent waving/straightening, and discoloration can increase the friction between the hairs. Conditioners, masks, and oils can help reduce friction and prevent damage to the hair.
The static load of hair
The hair's friction and high electric resistance can generate static load between the hairs. This creates flyaways and frizz that make hair difficult to handle. Moisture and humidity can help reduce the static load of the hair.
Shine
Shine is one of the hair's most desirable cosmetic attributes as it signals health and strength. As shine is a surface property, the cuticle is mainly responsible for it. Any damage to the cuticle and a build-up of dust particles and sebum can reduce the shine of the hair.
Figure 1. Shiny hair reflects light and its surface appears smooth.
Note: While a shiny and smooth surface can signal good hair health, it is important to note it’s not always the case. Some ingredients in hair products, such as silicones, can create a film on the surface of the hair, which helps to create a glossy look. However, the damage may not actually be repaired. In addition, a silicone coat on the hair shaft can prevent the hair from absorbing important nutrients.
Weathering factors or elements that negatively impact hair health
Weathering is the gradual deterioration of the hair due to everyday wear and tear. It can manifest as damage to the cuticle and the development of longitudinal fissures called split ends.
The hair shaft reflects an individual's hair care practices. The older part of the shaft, particularly the tip, has been exposed to more washing, styling, and cosmetic procedures such as bleaching, coloring, and perming. As a result, it may exhibit more signs of weathering compared to the root, which may be less porous and have different chemical properties.
Weathering can happen for several reasons. Below, we will explore the most common ones.
Figure 2. Visible signs of weathering on the hair shaft.
[Source: Healthy Hair: What Is It?]
Cosmetic alterations
Cosmetic alteration of the hair involves chemical processes that change the typical structure of the hair shaft. It includes coloring/bleaching, perming, or straightening the hair. Such procedures tend to alter the physical properties of the hair and can lead to damage. They may remove the outer layer of hair and break the internal bonds in the cortex.
Hair's affinity for different coloring and waving methods can vary, and damaged hair may also have a distinct affinity for hair products. Hair strength and resistance to damage from external factors depend on race and individual differences.
UV radiation
UV radiation, particularly solar UV radiation, is harmful to the scalp and hair. It can cause hair damage, such as loss of tensile strength and shine, embrittlement, split ends, and increased friction. It is due to UV radiation's ability to decrease hydration and improve the permeability of the hair.
It changes the keratin structure, including reactions in amino acids, sterols, and fatty acids. It can cause disruptions in sulfur bridges, lipid decomposition, and reduction in melanin. UV radiation can also bleach and degrade hair properties through the oxidation of melanin, which can lighten blond hair and change red and brown hair. This process is especially severe in chemically treated hair, such as dyed or chemically straightened hair.
Aging
Aging is a natural process affecting different body parts, including the hair. Some of the most visible signs of aging on the hair are greying, thinning, and balding. If you would like to learn more about what happens to hair with advancing age, you can find an in-depth summary below:
What Happens To Hair With Advancing Age?
How to maintain hair vitality
You can maintain healthy hair by taking proper care of it. Grooming and caring for hair involves using shampoos that help to clean the scalp and conditioners that help to keep it moisturised.
Haven't found the hair products that work best for you? Why not take a look at the Scandinavian Biolabs Hair Strength & Recovery Bundle designed to help rebalance the scalp, help strengthen the hair shaft, and help improve smoothness?
There are many different shampoos and conditioners, each with unique formulations. Many newly designed hair care products help to repair and improve the appearance of damaged hair by restoring the cuticle and cortex. Intensive conditioning treatments can help to improve the moisture retention and physical properties of the hair, resulting in enhanced shine.
Unsure what products could help you best to keep your hair healthy? Why not take our quick Hair Health Quiz to find out?
For healthy hair, keep heat away as much as possible. When using heat on hair, make sure to apply the heat-protecting serum. This will help you protect the hair cuticle and prevent damage to the hair protein.
In addition to grooming habits, it is crucial to maintain a balanced diet. A nutritionally rich diet can help you ensure that new hair growth is strong and healthy, and will help you to keep it as such for a longer period of time. Looking for more information on how to eat for healthy hair? Why not take a look at some of our other blog articles on hair nutrition?
FAQ
Can damaged hair be repaired?
It depends on how damaged the hair is. In some cases where the damage is minor, it might be possible to repair it with conditioning products, masks, or oils.
My hair isn't shiny and smooth. Does it mean that it's unhealthy?
As we've seen above, hair health is influenced by many factors, so we can get a more accurate picture by examining all of them. While dullness can certainly be a sign that hair is unhealthy, it is important to note that shine is a property that's hard to measure. In addition, certain hair types and colours can appear shinier than others.
Can split ends be repaired?
While some products might help to improve the look of split ends temporarily, they cannot be repaired permanently. Taking proper care of your hair can help you keep your ends intact for longer.
Disclaimer:
The information we provide is not intended to mitigate, prevent, treat, cure or diagnose any disease or condition. If you have any concerns about your health, please consult your doctor.
References
Sinclair, R.D. Healthy Hair: What Is It? Journal of Investigative Dermatology Symposium Proceedings (2007) 12, 2–5. doi:10.1038/sj.jidsymp.5650046
Robles Velasco, M.V., De Sá Dias, T.C., De Freitas, A. Z., Vieira Júnior, N.D., Sales de Oliveira Pinto, C.A., Kaneko, T.M., Baby, A.R. Hair fiber characteristics and methods to evaluate hair physical and mechanical properties. Brazilian Journal of Pharmaceutical Sciences (2009) vol. 45, n. 1, jan./mar. doi.org/10.1590/S1984-82502009000100019
Dawber, R. Hair: Its Structure And Response To Cosmetic Preparations. Clinics In Dermatology. (1996). 14, 1. doi.org/10.1016/0738-081X(95)00117-X
