Medically reviewed by Cynthia Cobb, DNP, APRN on April 22, 2020
Written by Kathleen Davis, FNP
Over styling, exposure to heat, chemical processing, and other habits can strip the hair of its moisture and natural oils, which can result in damaged hair. In some instances, however, hair damage can be due to a medical condition.
In this article, we discuss how hair can become damaged, how to treat it, and when to see a doctor.
What is hair made of?
Hair consists of two structures.
The hair bulb follicle is the living part located under the skin. The human scalp contains approximately 100,000 hair follicles.
The hair shaft is the nonliving part above the scalp’s surface. The shaft is composed of the protein keratin, which makes hair strong and flexible.
The shaft consists of three layers:
- Medulla: This is the innermost portion of the shaft that consists of air spaces and a thin core of cells.
- Cortex: This consists of long keratin fibers held together by hydrogen bonds, which gives the hair strength, flexibility, and elasticity. The cortex contains melanin, which gives the hair color.
- Cuticle: The cuticle is composed of overlapping, dead cells. It protects the fragile inner layers from damage. A healthy cuticle is smooth and flat, maintaining the hair’s moisture and bounce.
What happens to hair when it is damaged?
Hair damage can occur in a variety of ways.
Hair is porous, but a lipid-coated membrane prevents it from becoming waterlogged. According to an article in the International Journal of Trichology, when a person strips their hair of natural oils and moisture, it also causes the loss of this lipid layer, causing the hair to become extremely porous.
The article also states that brushing wet hair can cause it to stretch. Although stretching the hair up to 30% of its original length should not cause damage, stretching it to 70% may cause irreversible damage, and stretching it beyond 80% can cause fractures in the hair.
Grooming habits, chemical treatments, and environmental exposure can also cause weathering of the hair shaft and change the texture of the hair. This leads to breakage.
When hair is badly damaged, the outer cuticle lifts and becomes worn, and the overlapping cells no longer lie flat.
How to treat damaged hair
The best way to maintain healthy hair is to get regular haircuts and prevent damage from heat and other grooming habits.
Once a hair shaft splits, a person will need to trim the hair up to the point where the hair shaft is whole.
If a person does not remove the split ends, the split will continue up the hair shaft, leading to hair breakage and further damage.
For hair that is in the early stages of damage, hair treatment methods can smooth down the hair follicles, which may then help repair the look of damaged hair.
Conditioning
Everyday conditioners contain lubricating and anti-static substances.
They also lubricate the hair cuticles and help to keep the hair from absorbing too much water.
Deep conditioning
A person can also use leave-in conditioner treatments.
Products vary, but some reports suggest that a person should leave a deep conditioner on their hair for 20–30 minutes.
Deep conditioning helps smooth and seal the hair cuticles, allowing them to maintain moisture balance.
A person can buy hair conditioning products online here.
Hair glaze
Hair glaze coats and seals each hair shaft, smoothing the cuticles in a similar way to a conditioner.
Heat protection
Heat and ultraviolet can damage a person’s hair.
The sun can damage hair, reducing the protein and bond strength of the hair fiber. This makes hair weak, dry, and brittle.
Individuals who spend time in the sun should wear a hat or apply a UV protector product.
A person can buy UV protection for hair online here.
Oil application
Applying certain oils may help condition a person’s hair.
According to a 2015 article, oils can help prevent further damage. They can penetrate the hair and help reduce the amount of water the hair absorbs. This can then reduce repeated swelling and drying that causes hair damage.
Oils can also fill the gaps that occur between the cuticles and protect the hair from aggressive substances and provide lubrication of the shaft.
Coconut oil may reduce protein loss for undamaged and damaged hair.
Coconut oil is better than vegetable oils due to its low molecular weight, meaning that it is easier to enter the hair shaft.
A person can buy hair products containing coconut oil here.
According to 2019 research, extra virgin olive oil and coconut oil can protect the hair follicles from heat, restoring hair’s moisture.
Peppermint oil may also help maintain healthy hair, according to a 2014 study on mice.
Good nutrition
Vitamins and nutrients are essential for healthy hair growth and shine.
According to an article in Dermatology and Therapy, a diet that lacks vitamins, minerals, essential fatty acids, and proteins can lead to hair structural abnormalities and hair loss.
People should consume a balanced diet that contains a variety of products, including protein, fruits, vegetables, grains, and healthful fats.
Tips for healthy hair and scalp
According to the American Academy of Dermatology, these tips can help a person maintain healthy hair:
- Wash hair according to hair type: If a person has oily hair, they may need to wash it daily. If a person has dry hair due to age or chemical treatments, they should wash it less frequently.
- Use shampoo correctly: People should apply shampoo primarily to the scalp and not the hair.
- Always use conditioner: People should apply conditioner to the tips of the hair and avoid the scalp.
- Choose products carefully: A person should choose hair products appropriate for their hair type.
- Protect hair from chemicals and harsh substances: A person should use a swim cap when swimming to protect the hair from the chemicals such as chlorine.
What can cause damaged hair?
Hair damage and breakage tend to happen when a person exposes their hair to harsh conditions or over-styling practices.
These practices include:
- use of heated styling tools, such as blow dryers, flat irons, or hot combs
- chemical processing including perms, coloring, and bleaching
- overexposure to the sun and swimming pool chemicals
- infrequent hair trimming
- lack of conditioning
- brushing too often
In some cases, medical conditions can damage hair:
- Malnutrition: According to 2015 research, a person’s nutritional health has links to the quality of their hair. Vitamins A and B-12, folate, selenium, and iron may affect hair quality.
- Hormones: Hormone imbalances can cause a person’s hair to become thin or weak. Both polycystic ovary syndrome (PCOS) and menopause can cause a person’s hair to become thinner.
- Thyroid disease: Hypothyroidism, which occurs when the thyroid is unable to produce enough thyroid hormones, can cause thinning hair, according to the National Institute of Diabetes and Digestive and Kidney Diseases.
- Autoimmune disorders: Autoimmune connective tissue diseases, such as lupus and scleroderma, can cause a person’s hair to become fragile and thin.
When to see a doctor
Individuals who have damaged hair and experience other symptoms, such as fatigue, heat or cold intolerance, weight loss, excessive hair loss, or headaches, should consult a doctor for further evaluation.
A person should also see a doctor if they experience symptoms of PCOS, including:
- an irregular menstrual cycle
- excessive hair growth
- acne
- weight gain
- darkening of the skin
Summary
Overexposure to heat and chemical treatments often cause damaged hair.
Occasionally, damaged hair can be due to an underlying medical problem.
Individuals can try different treatment methods to help repair the damage, allowing healthy new hair to grow back.