Hair loss is a common phenomenon encountered daily. It is therefore normal to find a few strands on the pillow, on clothing or in the shower. But do you know the reasons for this hair loss? We explain everything in this article.
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Why do we lose hair every day?
Summary
- The progression of the hair life cycle
- Losing hair every day is normal
- Hair loss associated with health issues
- Sources
Published June 27, 2023,
updated on May 29, 2024,
by
Manon, Scientific Editor
—
5 min read
The progression of the hair life cycle.
The skin naturally possesses hair follicles. There are approximately 1 million on the head, which can produce up to 150,000 hairs depending on the individual. Each hair is composed of a hair shaft divided into three parts: the medulla, the cortex, and the cuticle. Originating from a hair follicle, each has its own life cycle that unfolds in three stages:
The anagen phase: This is the growth phase of the hair during which there is proliferation of the matrix cells that form the inner sheath of the root, the cortex, and the medulla of the hair shaft. The synthesis and pigmentation of the hair shaft only occur during this phase. Its duration determines the length of the hair.
The catagen phase: The first sign of the catagen phase is the cessation of melanin production, the pigment responsible for the colour of our hair, in the hair bulb. The hair stops growing but remains attached to its hair follicle.
The telogen phase: After the catagen phase, the follicles enter a resting stage, known as the telogen phase. The hair shaft eventually detaches from its follicle, which has already begun to produce a new hair beneath the skin.
Thelifespan of a hair lasts between 2 to 7 years depending on the individual. Once its cycle is complete, the hair follicle begins a new one. It is estimated that each hair follicle will undergo an average of twenty cycles until it is exhausted.
Losing hair every day is normal.
Each hair has its own life cycle. When a hair dies, it falls out to make way for another. As each hair has an independent life cycle, they do not all fall out at the same time.
It is estimated that our hair is made up of approximately 85 to 90% of hairs in the growth phase. The 10 to 15% remaining are dead hairs or are in the resting phase, that is, about to fall out. It is these dead hairs that we find every day on the hairbrush, on the pillow, etc. Generally, we lose about 50 to 150 hairs per day. However, this quantity can vary from one individual to another.
Hair loss associated with health issues.
It is normal to lose hair every day. Hair loss can be occasional or chronic, depending on several criteria. However, when you notice that you are losing a lot of hair or that your scalp is starting to thin, this could be a sign of a health issue.
Skin Diseases
Some illnesses can lead to an increased loss of hair. These may include infectious diseases or thyroid problems. However, there are periods during which hair loss intensifies, such as pregnancy, childbirth, and menopause.
The various diseases known to cause hair loss include: androgenetic alopecia, alopecia areata, seborrheic dermatitis, scalp psoriasis, and lupus erythematosus...
Diet, the foundation of healthy hair
Daily hair loss can also be exacerbated by a deficiency in one's diet. A lack of iron often increases the number of hairs that fall out each day. This is why hair loss is pronounced among vegetarians or women during menstruation.
Vitamin D also plays a pivotal role in hair loss. Indeed, hair follicles have Vitamin D receptors (VDR: Vitamin D Receptor) which, once activated, promote the initiation of the anagen phase. Therefore, a lack of Vitamin D does not facilitate the transition between the telogen-anagen phases.
A hormonal imbalance caused by stress or depression
When the body is in a state of stress, this impacts the production and functioning of many hormones. Oestrogen is the hormone that plays a crucial role in maintaining hair health. A higher amount of testosterone than oestrogen can thus accelerate the hair production process. The rate of hair renewal will therefore increase, but within a short cycle.
Sources
PRICE V. H. Treatment of hair loss. The New England Journal of Medicine (1999).
RASHEED H. & al . Serum Ferritin and Vitamin D in Female Hair Loss: Do They Play a Role? Skin Pharmacology and Physiology (2013).
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