The following is a collection of concepts that helped me better understand the causes of hair loss. Please always refer to your health care provider for professional advice.

Causes of hair loss

Normal hair shedding

It's normal to lose hair. We can lose between 50 and 100 hairs a day, usually without noticing.

This is true for both women and men. Generally, if you see some hair on the floor, on your pillow or sticking in your brush, there is nothing to worry about. Although 50 to 100 hair can actually feel like a lot, especially if you have long hair, that is considered normal shedding.

Important concepts

To fully understand how to keep hair longer, we need to understand a few important concepts first.

1. Stages of hair growth

Growing phase (Anagen): This stage usually lasts 3 to 5 years. Roughly 90% of your hair are in this phase at any time.

Transition phase (Catagen): Hair growth slows. It usually lasts 10 days, and only about 5% of your hair are in this phase.

Resting phase (Telogen): This lasts about 3 months. About 10 to 15% of your hair prepare to shed.

Shedding phase (Exogen): This final phase lasts around 2 to 5 months. Old hair shed, leaving space for new hair to grow.

2. The concept of "losing" hair

There is a common misconception: we become bald because our hair detaches itself from the scalp and never comes back. This, except for some serious medical conditions, is not true. It is imperative to understand that hair loss is a gradual process, and it is caused by the shrinking of our hair follicles.

Shrinking happens when hair goes from the shedding phase to the growing phase. Basically, they grow thinner and thinner each time, until they disappear. But why is this happening? Note down this word: DHT.

3. DHT our friend, yet our hair's biggest enemy

If you are affected by hair loss your hair is, most likely, susceptible to a hormone called Dihydrotestosterone, often called DHT" for short. DHT is derived from testosterone, and it is of vital importance for our body. However, it is believed to gradually shrink hair follicles in men and women with hair sensitivity to DHT.

DHT is what defines male sex characteristics when you go through puberty. Together with testosterone, it has many other benefits such as maintaining muscle mass and promoting sexual health and fertility.

Eliminating or strongly lowering DHT, since DHT can be so useful to the body, is not a great idea. But reducing it to a suitable level may help to stop or even revert hair loss.

What is DHT's suitable level to prevent hair loss?

There is no real answer to this question, and the reason is because everyone is different. Our bodies do not react the same to lowering DHT, thus lowering DHT may have different results when it comes to stopping hair loss.

It is also important to differentiate between plasma DHT and scalp DHT. Plasma DHT flows through our body and is responsible for all the good things mentioned above, whereas scalp DHT is present on top of our head, exactly where our beloved hair grows. With this distinction in mind, the goal of most of hair loss treatments is to reduce the amount of scalp DHT.

Please see the dedicated treatments tabs for ways to reduce DHT.

4. The unwritten 50% rule

According to several hair restoration doctors, only hair follicles that lost less than 50% of their original size can be saved with hair loss treatments. For instance, if your original hair diameter is 80 micrometers, it is possible to prevent the hair to disappear only if the treatment starts before the diameter shrinks below 40 micrometers.

Types of hair loss

Male and female pattern hair loss

Hair loss that primarily affects the top and the front of the scalp is called "pattern hair loss." It is believed to be connected to genetics. If you look into your family tree, there is a good likelihood that one of your close relatives is affected with a certain degree of hair loss. Being aware of this can help you to start treatment early enough.

Marco's note: "My father has a full head of hair at 77. My grandpa from my mom's side was bald as a potato. Thanks to my grandpa, I made and use this app ;-)"

Men

To classify pattern baldness in men, the simplified Hamilton-Norwood scale comes to help:

Norwood 1 and 2 can be also referred as mature hair lines. As we grow old, our hairline can slightly recede without necessarily be considered hair loss.

Women

There are three clinical manifestation of women pattern hair loss.

The first is diffuse thinning in the region of the vertex and in front of the vertex towards the head front. This pattern leaves the frontal hairline intact. The severity can start from mild thinning until complete baldness.

A second manifestation is a thinning of hair that appears in triangular or Christmas tree form.

A third, even though considered less common, is a deep recession of the hairline, similar to the one typically seen in men.

The diagnosis for women is not an easy task, and I strongly recommend talking with your health care provider if you experience thinning.

You can read more in this great article:

Alopecia areata

Alopecia areata, on the contrary, is a disease. The body's immune system attacks the hair follicles, and this results in localized hair loss. This can happen in any part of the body, including the scalp, nose, ears, and even eyebrows.

Currently, there is no cure for alopecia areata, but some treatments can help preventing the immune system to attack the follicles and to stimulate regrowth.

If you notice localized patches of hair fall, it is advisable to promptly seek medical attention.

Stress

Prolonged stress affects our body in many ways. One possible consequence of stress is a noticeable thinning of your hair. Why does this happen?

The technical term for this is "Telogen effluvium." Basically, significant stress can push large numbers of hair into the resting (telogen) phase. After 2-3 months, this can result in important hair fall.

Marco's note: "A couple of years ago, I helped a friend to overcome depression, and it took us about a year to see good results. Even though I would do that again, I must admit that I had to cope with a lot of extra stress. After six months, I noticed a thinning in my temples and forehead. I would say a good 30%. Luckily, after my stress level decreased, the thickness came back where it was before."

Hairstyle pulls

Pulling your hair violently will cause the follicle to be pulled off the scalp. Yet, also prolonged pulling can lead to permanent hair loss. This can happen if long hair is tightly pulled back with regularity.

Medications and cures for cancer

Some kind of medications, including chemotherapy, may cause hair loss. Usually, the hair will fall more aggressively, and healthy hair will be affected. Radiation is also another cause of hair loss. Hair will be likely regrow within weeks/months of finishing such therapy.

Other causes of hair loss

There are several less occurrent causes of hair loss. These include scarring alopecia, poisoning, child birth, friction, scalp infection, hormonal imbalance, and even hair care products.

Due to the long list of possible causes, it is always advisable to consult your health care provider before coming to conclusions and starting treatments on your own.

Sources