Hair follows a cycle
Losing hair is not in itself unusual. Hair does not simply keep growing; it repeats a cycle of growing, resting, and shedding.
The cycle has three phases. The anagen phase, when hair grows, is the longest, and most of the hair on the head is in it. Next comes the short catagen phase, when growth stops, followed by the telogen phase, a resting period lasting several months. When the telogen phase ends, a new hair pushes up in the same spot and the existing hair falls out.
Hair is known to grow about 0.3 to 0.4 millimeters a day, roughly 1 centimeter a month.
Even a healthy scalp sheds a certain number of hairs each day. What matters is not the number shed so much as whether new hair comes up properly where the old hair fell out, or whether the balance of the cycle has broken down.
Androgenetic hair loss: the cycle shortens
This is the most common type. The name covers both male-pattern and female-pattern hair loss, and genetic predisposition along with the male hormone androgen are regarded as important factors.
Its hallmark is not that hair falls out all at once but that the cycle changes. The anagen phase grows shorter and the proportion of hair in the telogen phase increases. Hair that has not had enough time to grow becomes thin and short and lighter in color. That is why the number of hairs may remain while the overall look becomes sparse.
There are tendencies in how it progresses as well. In men, the hairline receding or the crown thinning is common; in women, a broad thinning centered on the part line is more frequent.
Because it progresses gradually, by the time a person notices it, a considerable amount of time has often already passed.
Alopecia areata: the immune system is involved
This type produces coin-shaped patches with clearly defined borders. It is regarded as an autoimmune condition. The explanation is that the immune system mistakenly identifies hair follicles as targets, and the hair in that spot falls out.
It may appear in a single spot or in several places at once. It can occur not only on the scalp but also in the eyebrows or beard.
Unlike androgenetic hair loss, the follicles themselves are not lost, so recovery does occur in some cases. However, when the area is wide or the condition recurs, the course varies and is hard to predict.
Stress is often mentioned as a trigger, but it does not explain the condition on its own. If sharply bordered hair loss appears suddenly, it is worth having the type confirmed.
Telogen hair loss: everything shifts at once
The third type often has a relatively clear cause. It appears after a major burden on the body, such as childbirth, surgery, high fever, rapid dieting, severe stress, or certain medications.
The mechanism works like this. Hairs that would normally enter the telogen phase at different times all shift into it together following the triggering event. Then, a few months later, they shed at the same time. Being alarmed by clumps of hair coming out while washing falls into this category.
The key point is the time lag. Because the shedding happens several months after the cause, it is easy to feel that nothing particular is going on right now and wonder why the hair is falling out.
When the cause is resolved, recovery often follows. However, if the cause persists or another type overlaps, the course is different.
| Type | Contributing factors | How it presents |
|---|---|---|
| Androgenetic hair loss | Genetic predisposition and androgen are regarded as important factors | The anagen phase shortens, hair becomes thin and short, and it progresses gradually |
| Alopecia areata | Regarded as an autoimmune condition | Coin-shaped patches with clearly defined borders; can also occur in the eyebrows or beard |
| Telogen hair loss | Childbirth, surgery, high fever, rapid dieting, severe stress, certain medications | Hair shifts into the telogen phase all at once and sheds together several months later |
How is the type identified?
It is difficult to determine the type from the pattern of shedding alone, because overlapping types are common.
The first thing we look at is distribution. Whether the hair falls out in sharply bordered round patches, whether specific areas such as the hairline or crown are thinning, or whether the thinning is even overall, points in different directions.
The thickness of the hair itself is another clue. In androgenetic hair loss, thick and thin hairs are mixed within the same area. This is the result of hair with a shortened cycle not growing enough. That is why magnified examination of the scalp and hair is used.
General health is reviewed as well. When telogen hair loss is suspected, we check for childbirth, surgery, fever, dieting, or medications over the past several months, and look at items such as thyroid function and iron status.
This is why the patient interview matters. The current appearance alone makes it hard to trace a cause that occurred months earlier.
The approach differs by type
This is why the type has to be identified first. When the cause differs, what needs to be done differs too.
For androgenetic hair loss, slowing the progression is the primary goal. Rather than reviving follicles that are already gone, the focus is on reducing the rate at which the remaining hair thins. Medication has long been used, and consistency is the key.
Alopecia areata is approached through the immune response. For telogen hair loss, finding and resolving the cause comes first, and factors such as nutritional status and thyroid function are checked alongside.
There are also approaches aimed at the scalp environment. Injecting autologous stem cells obtained from fat (SVF) or growth factors into the scalp to improve the environment around the follicles falls into this category. TheLINE Plastic Surgery's SVF hair treatment is one of these. However, suitability differs by type, so examination and diagnosis must come first.
What lifestyle contributes
Hair loss cannot be prevented by lifestyle habits alone, because genetic predisposition and immune factors are involved depending on the type. Still, the factors that make the condition worse can be reduced.
Nutrition is a leading example. Hair is made of protein, and trace nutrients such as iron and zinc are involved in its growth. When rapid dieting leaves intake insufficient, the body cuts resources first from the areas least urgent for survival. Hair is one of them.
Sleep and stress are involved as well. Rather than being direct causes, they are mentioned as triggers for telogen hair loss.
Scalp irritation is also worth reviewing. Scrubbing too hard, washing too often, and conversely leaving the scalp so long that sebum and dead skin build up all place a burden on the scalp environment.
How the hair is tied up can also become a problem. Pulling the same spot for long periods can cause traction hair loss, in which hair in that area falls out.
Points to keep in mind
No method revives follicles that are already gone. Areas where follicles have been completely lost require a different approach. That is why checking at an early stage is said to be advantageous.
Results take time to appear. Because the hair cycle itself runs in months, it is hard to judge within a few weeks. Observing the course over at least several months is standard.
Outcomes vary considerably between individuals. Genetic predisposition, how far it has progressed, age, and general health all play a part.
Overlapping types are also common. For example, telogen hair loss brought on by childbirth or dieting may overlap with androgenetic hair loss that has been progressing gradually. In such cases, addressing only one may fall short of expectations, so we recommend sorting out the condition first through examination and interview.
Frequently Asked Questions
How many hairs a day is normal to lose?
Even a healthy scalp sheds a certain number every day. More important than the number itself is whether new hair comes up where the old hair fell out and whether the hair is thinning overall.
Can stress alone cause hair loss?
Severe physical or mental strain can be a trigger for telogen hair loss. However, not all hair loss is explained by stress, and the cause differs by type.
When can results be seen?
Because the hair cycle runs in months, it is hard to judge over a short period. Observing the course over at least several months is standard.
Do women get androgenetic hair loss too?
Yes. However, it progresses differently: rather than the hairline receding, broad thinning centered on the part line is more common.
Once treatment starts, does it have to continue?
It depends on the type. Some types recover once the cause is resolved, while others aim at slowing progression and require ongoing management.
How is hair treatment carried out at TheLINE Plastic Surgery Clinic?
TheLINE first identifies the type of hair loss through examination and patient interview, because the approach changes with the type. Autologous SVF is used as a way of approaching the scalp environment, and since the hair cycle runs in months, we do not judge over a short period but review the course together with the patient.
