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Hair Loss: How to Stop It?

Hair Loss: How to Stop It?

Published: 22 November, 2023 | 9'

Hair is one of the characteristic features in humans, with a high symbolic value as the style or hairstyle is a means of social communication and identity projection. It is the area of our body that we care for the most and throughout history, it has been associated with beauty, attraction, and self-esteem. Furthermore, from a sociological point of view, it is frequently linked as a marker of age, health, nutrition, and fertility.

The hair has three main functions: protection against external factors, thermoregulation, and the production of sebum and pheromones.

Hair is a derivative of the epidermis and consists of two well-differentiated parts: the follicle (where the hair grows) and the hair shaft (the hair itself). Let's see how it grows and the reasons why we lose hair.

Why does our hair fall out?

The scalp contains around 100,000 hair follicles with different degrees of growth. The average life cycle of a hair is about 3.5 years, with a growth rate of 0.05 centimeters per month.

The hair follicle is responsible for nourishing the hair, the volume of the hair fiber and its thickness, and the speed and regulation of hair growth. Additionally, the hair follicle is subject to a constant and perpetual renewal through three hair regeneration phases:

  • Anagen (proliferation): This is the growth phase and it lasts from 2 to 7 years. The volume of hair can change between 85% and 90.6%. It is the most vulnerable phase in case of factors that negatively affect its development. In general, it is longer in women than in men.
  • Catagen (involvement): It lasts approximately 2-4 weeks. The volume of hair can vary between 1% and 2%.
  • Telogen (rest): It lasts about 3 months and the volume of hair varies between 10% and 15%.

This hair renewal, where there is hair loss, is a normal cycle of the hair follicle's metabolism. When any of these phases becomes imbalanced, especially the anagen phase, excessive hair loss, reduction of hair thickness, slow growth, among other issues, can occur.

How much hair do we lose per day?

As previously mentioned, hair loss due to the hair regrowth cycle is normal. It is estimated that between 50-100 hairs fall out per day under normal conditions. However, it can become a problem when the loss is above 100 hairs and lasts for several weeks. In these cases, the recommendation is to consult a professional who can evaluate the cause and provide guidance on the most appropriate treatment.

Main causes of hair loss

Hair growth and its regrowth phases are influenced by numerous factors. Internal factors are mainly related to genetics, hormonal action, nutrition, among others, while external factors are associated with environmental causes, climatic conditions, occupational practices, hair hygiene products, etc. Let's look at some of these causes.

Effects of stress and anxiety

Stress is a normal reaction to the pressures of everyday life. This reaction causes physiological and psychological changes in order to activate or act efficiently and coherently in different situations. The hormone cortisol is mainly responsible for stress-related reactions; in fact, it has been shown that cortisol has a negative effect on the hair follicle formation mechanism, especially its structure.

Similarly, changes occur at the immune, hormonal, and cardiovascular levels, which are closely involved in the hair follicle metabolism. Both stress and the changes that occur should not be permanent, so hair loss should be temporary. However, if the stressful situation continues and is not properly managed, it can lead to longer-lasting alterations.

There are two types of hair loss associated with stress:

  • Telogen effluvium (TE): This is characterized by a large number of hair follicles entering the resting (telogen) phase and the thinning of the hair. It is classified into acute (6 months) is similar to acute telogen effluvium, with hair loss and diffuse thinning of the hair, as well as a shortening of the anagen phase. Women between 30 and 60 years old are most affected.
  • Alopecia areata (AA): This is a hair loss of autoimmune origin, characterized by localized areas with a noticeable reduction in hair. It mainly affects the hair proliferation phase and is reversible when properly treated.

Seasonal changes

Changes in temperature exert thermal stress on the hair follicle. During the summer, the hair cycle tends to be in the resting (telogen) phase, transitioning to the involutive (catagen) phase in autumn, resulting in hair loss. During spring, although to a lesser extent, the hair goes through the catagen phase and the cycle restarts with hair growth.

Genetic components

Genes determine the thickness, volume, curvature, and color of the hair, among other characteristics. They also regulate the hair growth cycle. The so-called androgenetic alopecia (AGA) is the most common cause of hair loss. AGA is caused by both genetic factors and those related to age. Statistics indicate that it affects 80% of males (50% at the age of 50 and 70% in older age) and 40-50% of females (16% below the age of 50 and 30-40% above the age of 70). It is important to note that the genetic component for developing AGA is only 21% in women, while for men, it is 50%.

The androgenic mechanism is related to the regulation of the enzyme 5-alpha reductase and other prostaglandins. This androgenic mechanism allows vellus hair to convert into longer, thicker, and darker terminal hair. Dysfunction in this mechanism stimulates the regression of hair follicles, causing what is known as follicle miniaturization (the follicle becomes very small).

The importance of nutrition

The normal functioning of the hair depends to a large extent on a proper and balanced diet. Of the more than 100,000 hair follicles present on our scalp, 90% are in the anagen or proliferation phase, making the supply of nutrients such as proteins, vitamins, and minerals crucial for maintaining healthy hair. Furthermore, it has been observed that several micronutrients minimize oxidative stress because they play a role during alopecia.

In general, hair loss (without dandruff problems) occurs in diffuse hair loss, chronic telogen effluvium, androgenetic alopecia, and alopecia areata. Deficiencies in iodine, biotin, inositol, niacin, pantothenic acid, among others, can cause hair loss.

Hair loss in men

In men, androgenetic alopecia (AGA) presents a pattern of hair loss known as male pattern hair loss (MPHL). It is characterized by thinning on both sides of the frontal scalp, along the hairline, extending to the vertex. The rate of progression varies from individual to individual, with clinical heterogeneity among affected family members and racial variations in clinical presentation.

As mentioned earlier, AGA is caused by dysfunction of 5-alpha reductase, which is involved in converting testosterone into dihydrotestosterone (DHT). When DHT levels rise within the hair follicle, the hair cycle is shortened, the follicle shrinks, and as a result, hair becomes thinner and of poorer quality, leading to hair loss.

Hair loss in women

In women, the pattern of hair loss (FPHL) related to AGA is more diffuse and accentuated in the frontal and mid-scalp regions, and in some cases, it can affect the parietal or occipital area. Similar to men, the enzyme 5-alpha reductase may be involved as it also affects estrogen metabolism, weakening the hair follicle.

The prevalence of AGA in women is more common after the age of 70, while hair loss during adolescence, reproductive age, and menopause indicates that hormonal cycles during these times influence the hair cycle.

Pregnancy, Postpartum, or Lactation

The hormonal changes that occur during these three stages are determined by elevated levels of estrogen, progesterone, gonadotropin, prolactin, as well as growth factors. Let's explore what happens to the hair during these changes.

  • During pregnancy, the combined action of these hormones delays the catagen phase, increases the growth rate and hair diameter. Prolactin and progesterone inhibit the activity of 5-alpha reductase, which is responsible for hair loss.
  • The rapid decrease in estrogen and progesterone levels during postpartum leads to telogen effluvium (TE) that can last between 2 to 4 months. TE stimulates synchronized hair shedding for 6-24 weeks, and it rarely extends beyond 15 months.
  • When the release of breast milk begins and prolactin levels remain elevated, telogen effluvium reverses, and the hair cycle returns to normal with a balance between the anagen and telogen phases.

Hormonal Changes

Other changes in hormone levels directly affect the hair growth cycle. Some are related to stages of sexual development, while others are due to external factors or internal dysfunctions.

During puberty, the release of androgens stimulates the growth of body hair and hair growth. Thyrotropin (produced by the thyroid) positively influences the hair follicle, elongating the hair shaft and promoting the anagen phase.

On the other hand, high levels of corticotropin and cortisol (related to stress) stimulate the catagen phase and inhibit the production of hyaluronic acid and proteoglycans that are essential for the hair follicle. Another factor that can contribute to hair loss is an imbalance in levels of the neuropeptide galanin, which also regulates the hair cycle and participates in appetite sensation, memory, and learning processes.

Menopause is another stage where hormonal changes affect the hair growth cycle, resulting in a marked decrease in hair density and hair diameter. The cessation of ovarian estrogen production and interactions with other hormones, growth factors, and cytokines contribute to altering the characteristics of hair growth. Androgens levels persist longer, and increased luteinizing hormone not only causes hair loss but also modifies the balance between the anagen and catagen phases. The areas with the least hair presence during this stage are located parietally and fronto-sagittally.

Natural Solutions to Stop Hair Loss

It is widely recognized that the nutrients we obtain from food provide the energy and essential elements for the growth, repair, and maintenance of our tissues and organs, including the scalp. Therefore, a balanced diet is crucial for maintaining good hair health. Let's review the key natural ingredients that promote hair growth.

The Importance of Zinc and Biotin

  • Biotin: is essential for the production and breakdown of proteins, fats, and carbohydrates in the body. It plays a role in the production of keratin and collagen proteins and contains sulfur, which promotes hair growth and regulates sebum production. Biotin can be found in plant-based foods (mainly in cereals, vegetables, and some nuts) and animal-based foods (liver, eggs, and milk). The recommended daily intake of biotin for adults is 40 µg/day, with maximum doses between 1000-2000 µg/day.
  • Zinc: plays a key role in the antioxidant system of the scalp and collagen production. It regulates androgen activity in the hair follicle and the catagen phase, promoting hair growth and increasing thickness and strength. The main dietary sources of zinc are fish and meat, and the recommended daily intake for adults is 10-12 mg, with a maximum intake of 25 mg/day.

The Role of Collagen and Keratin

Collagen and keratin form the structure of both the hair follicle and hair shaft. Collagen provides firmness and elasticity to the surrounding skin, while keratin provides firmness, elasticity, and shine, and stimulates hair growth factors.

Cystine and Methionine

These sulfur-containing amino acids form the structure of hair keratin proteins. Cystine is the main amino acid found in keratin (10-17%), and its production is regulated by certain growth factors. Cystine presence favors hair growth, diameter, firmness, and protein synthesis.

Food sources of these two amino acids include animal sources such as tuna, salmon, shrimp, beef, lamb, eggs, and dairy products, as well as plant-based sources such as red peppers, onions, cereals, beans, lentils, soy, wheat germ, and spirulina.

Saw Palmetto

The extract or oil obtained from the berries of the Saw Palmetto plant is rich in fatty acids. Its activity enhances the antioxidant capacity of the scalp, regulates the activity of 5-alpha reductase, and its active component, beta-sitosterol, has a positive effect on the anagen phase.

Hyaluronic Acid

Hyaluronic acid is a polysaccharide present in all our connective tissues, including the skin and scalp. Its presence in the hair follicle is crucial for maintaining viscoelasticity, moisture, and regulating metabolism. Furthermore, hyaluronic acid allows the construction of other essential components of the hair follicle, such as proteoglycans.

Final Recommendations to Prevent Hair Loss

Hair is one of the defining features of our appearance and requires proper care. A healthy diet that provides the necessary nutrients for hair health is essential and can be complemented with dietary supplements.

There are various reasons for hair loss, from factors like stress and hormonal changes to climate variations. It is crucial to identify the underlying cause and seek professional advice to implement appropriate measures that restore a healthy hair cycle.


Content written and reviewed by MARNYS Scientific Information team. This article is for informational purposes only and does not replace consultation with a healthcare professional.