Understanding hair loss

It’s not unusual for people to experience hair loss. On average, we lose between 50 and 100 hairs a day as part of the natural regeneration process. However, as there are approximately 100,000 hairs on our scalp, this hair loss doesn’t cause noticeable thinning. Unfortunately, many people experience far more advanced hair loss and the condition is very common in both men and women throughout the UK.

The Different Types of Hair Loss & Causes

While our hair naturally thins with age, there are also a number of other factors that can contribute to more advanced hair thinning.

Hereditary baldness or thinning (androgenic alopecia)

This is the most common form of accelerated hair loss in both men and women, accounting for approximately 95 percent of cases. Genetics impact hair growth and can trigger androgens (a class of hormones) that promote the shrinkage of hair follicles on the scalp. Consequently, women can experience hair thinning at the top of the scalp, while men often develop bald spots on top of the scalp or on the forehead area. Approximately 50 percent of people have symptoms of inherited hair loss by the time they reach 50 years of age.

Other forms of alopecia

Cicatricial (scarring) alopecia is a rare disease that attacks hair follicles and causes scaring. The scar tissue prevents the hair from re-growing, leading to patchy baldness. Another cause of baldness is alopecia areata. This is an autoimmune disease that attacks hair growth, causing round, smooth patches of hair loss. Both these types of alopecia can occur in otherwise healthy individuals.

Health issues

Hair loss can be a symptom of a more serious underlying condition. There are a number of diseases, such as anaemia and thyroid disease, that can cause hair loss. Hair thinning can also occur following an illness, such as a severe infection, high fever, flu or surgery. Untreated ringworm infections can also cause hair loss.

Trichotillomania is an unusual medical condition whereby patients are unable to control the urge to twist or pull their hair until it breaks away. It’s thought to affect approximately 4 percent of the population, with women more susceptible to this impulsive disorder than men1. It can cause significant hair thinning and patchiness.

Stress & Hormones

Traumatic events (e.g. divorce or death of a loved one) can cause hair loss. Changing hormones during menopause and following child birth will trigger hair loss. This is usually temporary thinning, although women 40 years and older can expect to have less hair than when they were younger.


Some medications can cause hair loss, such as blood thinners, birth control pills, excessive doses of vitamin A, and anabolic steroids. Various medications used to treat blood pressure, depression, heat conditions, arthritis and cancer, can also promote hair loss.

Other factors

Certain hairstyles and hair maintenance practices can cause damage to the hair shaft and root, sometime leading to thinning. Diet and lifestyle factors can also influence hair health.

Understanding Hair Anatomy

By understanding the anatomy of hair, it’s possible to investigate suitable treatments to prevent hair loss.

Hair can be divided into two main parts, the shaft and the root. The root is embedded into the epidermis surrounded by a follicle and intercepted by capillaries and nerve fibres. The hard hair shaft is formed as new cells divide, push up and die. The shaft is comprised of three layers, the cortex, medulla and cuticle. The cortex is the inner layer between the medulla and cuticle. It determines the strength and bulk of the hair. The innermost layer is the medulla, and the cuticle is the outer, transparent layer designed to protect the rest of the hair shaft.

These components of hair are comprised principally by structural proteins known as keratin, specifically a-keratins. Keratin is also the key protein that makes up the outer layer of human skin and nails. This fibrous protein arranges itself in parallel sheets bound by hydrogen bonding to provide structure and strength. Collagen is also another important protein associated with hair growth, health and protection.

How Amino Acids Can Protect Against Hair Loss

There are four amino acids that are particularly important in the formation of keratin. They include cysteine, lysine, arginine and methionine. Lysine and methionine are essential amino acids and must be sourced from our diet. Increasing the availability of amino acids associated with keratin production can help to promote hair growth and combat hair loss.

Not only is arginine important for the synthesis of keratin, it’s also the precursor for nitric oxide (NO), making it essential for hair growth. Nitric oxide opens potassium channels and this improves blood and nutrient supply to the roots and promotes hair growth. Studies have shown that arginine can also protect hair from the damaging effects of bleaching or hair colouring2. Also, as arginine is an important amino acid for supporting the immune system, it can play a role in reducing disease-related hair loss.

While the body can produce arginine, during periods of stress the body’s demand for this amino acid can increase. This may occur simply as a response to poor diet or daily stress. Boosting arginine levels through diet can help, especially when the hair loss is a symptom of an underlying disease.

Some of the best animal dietary sources include poultry, dairy, beef and fish. Other good plants sources include oatmeal, wheat germ, chick peas, sesame seeds, soybeans, pumpkin seeds, granola, nuts and sunflower seeds.

This amino acid is an integral building block of keratin, accounting for approximately 24 percent of the protein. Several studies have shown a significant improvement in androgenic alopecia as a result of cysteine supplementation3. Cysteine is also an important amino acid in the formation of glutathione, an extremely potent antioxidant. Consequently, cysteine also has a role to play in the protection of the sensitive hair root structure from oxidative stress.

Like arginine, cysteine is produced from within the body. However, a regular intake of cysteine rich foods can help boost levels of this important amino acid. Good animal sources include pork, poultry and dairy. While broccoli, legumes and whole grains all offer a good plant source.

The second largest component of keratin is methionine. Like cysteine, methionine is also a sulphur containing amino acid and is essential for the production of procollagen (the precursor to collagen). Without methionine, hair growth will subside and hair health decline4. Methionine is also an important free radical scavenger and reduces oxidative stress on hair follicles. Research has suggested that this amino acid may have a role to play in reducing or preventing hair loss, as well as greying of the hair5.

Methionine must be sourced from our diet as it cannot be manufactured within the body. Ideal food sources include eggs, fish, soy, nuts and seeds.

This amino acid has a major role in the stimulation of collagen production and is thus important in the repair of damaged hair. Roots also require lysine to correctly function. Studies have shown that lysine supplementation can help to reduce hair loss 6.

Foods rich in lysine include dairy products, fish (sardine, cod and salmon in particular), red meat, pork and poultry. Other top sources include legumes, pulses, spirulina and nuts.

How Nutrients Can Protect Against Hair Loss

In addition to amino acids, certain vitamins and minerals also play a key role in the health of hair. Vitamin A is important for supporting the sebaceous glands that lubricate and protect hair follicles. Vitamins B12, B6, E and folic acid are required to keep hair follicles healthy through regulating haemoglobin within the blood and promoting good circulation. Vitamin C is important for collagen synthesis and thus, essential for keeping hair strong and preventing split ends and hair breakage. Zinc, silica and iron are also important minerals needed for hair growth and protection.


Hair loss and balding are very common conditions, particularly prevalent in the older generation. While the majority of cases are closely linked to genetics, it’s still possible to slow the process of hair loss. As we get older, oxidative stress within the body damages cells and make us more susceptible to the effects of aging and more vulnerable to certain diseases. Also, hormonal changes and an increase in androgens are common. Hair loss can occur as a consequence of these processes.

By boosting amino acids associated with hair growth, maintenance and protection, it’s possible to reduce hair loss. Amino acids such as methionine, cysteine and arginine will also help to slow the aging process by reducing oxidative stress. These amino acids can also help to restore hormonal balances. Through a balanced diet full of amino acid and nutrient rich foods, it’s possible to support healthy hair and protect against hair loss. There are also a wide range of dietary supplements available that are especially formulated to promote healthy hair growth and maintenance.

  1. “http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002485/”
  2. “http://www.ncbi.nlm.nih.gov/pubmed/15645092
  3. “http://onlinelibrary.wiley.com/doi/10.1111/j.1610-0379.2011.07802.x/full”
  4. “http://jcs.biologists.org/content/119/3/391.short”
  5. “http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2929555/”
  6. “http://www.ncbi.nlm.nih.gov/pubmed/18498491”