While it is normal to lose around 50 to 100 hair strands daily, alopecia (the medical term for hair loss) only happens when there is excessive shedding of hair and when the body is unable to replace the lost hairs. There are several reasons why this can happen. Below are probable causes of hair loss, and why each of them makes such an impact in one’s hair growth.


Genetic Makeup

This is the most common cause of Androgenetic/Androgenic Alopecia (which accounts for 95% of all hair loss cases).

People can inherit hair follicles with genetic sensitivity to Dihydrotestosterone (DHT), which is a byproduct of testosterone. Testosterone converts to DHT when it enters the scalp and gets in contact with an enzyme called the Type II 5-alpha-reductase, which is found in the oil glands of the hair follicle. If a hair follicle is sensitive to DHT, it begins to shrink in size. As it gets smaller, it will produce weaker, shorter hairs. Within a few years, this follicle would have shrunk so much that it would be barely visible. At this point, it will no longer be able to produce hair.

The good news is, although most of the hair loss cases can be attributed to our genetic makeup, with proper and early intervention, the condition is highly preventable and treatable. As long as DHT is suppressed, hair follicles will continue to stay healthy and will facilitate hair growth.


Medical Conditions and Treatment Side-Effects

Underlying illnesses can directly or indirectly cause hair loss. Here are some of the medical conditions and their treatment side-effects that can lead to hair loss:

Contrary to popular belief that people with cancer automatically lose their hair because of their illness, it’s actually the medications that cause this. Chemotherapy drugs designed to fight cancer cells are normally very strong. Since they are designed to attack rapidly growing cancer cells, unfortunately, they also attack other growing cells in the patient’s body — like those found in hair roots. This prevents the circulation of oxygen in the hair shaft which kills existing hairs and prevents new growth. Radiation therapy used in treating cancer also causes hair loss in the areas where the radiation is aimed. Depending on the dose and method used for the radiation treatment, hair loss can be temporary or permanent.

Thyroid Disease

Thyroid disease causes hormonal imbalance. It can make one’s hormone levels to drop or rise to unhealthy levels. This imbalance can then lead to hair loss.As mentioned in our Introduction to Hair Loss, each hair strand goes through a cycle of growing and resting. At any given time, around 85% of one’s hair is growing, and only a small portion is resting. However, when the body’s hormone levels go haywire, the hair cycle gets disrupted. A bigger percentage of hair will be resting instead of growing, causing more hair fall and less hair growth which results in hair thinning, hair loss, and balding.


Hair loss can be caused by the lupus disease itself (as it triggers the immune system to attack hair follicles) and by the medications used for treating it (like immune system-suppressants and prednisone). These can cause hair strands or clumps to easily fall out even with just the slightest pull. They also cause hairs to become so thin that they easily break.Once lupus is cured though and once the medications are stopped, the follicles would be able to produce new hairs again. It might take a long while though. An exception to this is the skin lupus which leads to discoid rashes. These rashes are red, scaly, and thick that can scar hair follicles, making them permanently unable to produce hair again.

Polycystic Ovarian Syndrome

An endocrine disorder more commonly known as PCOS, this condition affects women only. It makes the body produce excessive amounts of male hormones called androgens. Women who are genetically predisposed to sensitive follicles will experience a decrease in hair growth due to the high levels of androgens in their body.
One type of androgen is testosterone which, as discussed earlier, becomes DHT when it reacts to an enzyme in the hair follicle’s oil glands. The heightened levels of androgens therefore facilitates for an overproduction of DHT that shrinks follicles and affects their performance in producing, nourishing, and growing hair.


Psoriasis is a dry and scaly skin disease caused by underlying cells reaching and dying on the skin’s surface and scalp. Red plaques resulting from psoriasis eventually flakes off, taking with them thin, weak, and brittle hairs.

Scalp infections

Ringworms that come with infections invade the very sensitive skin of our scalp, affecting parts of it which result to coin-like patches and thinning of hair.


Stress and Anxiety

Body systems do not function normally when a person is under stress. It also causes the scalp capillaries to become spasmed, preventing hair follicles from getting nourishment because the circulation of blood is disrupted. When stress becomes chronic (leading to anxiety), the hair follicles shrink, causing the hairs that they host to fall off. These follicles will also produce unhealthy and weak hairs.

Stress and anxiety also makes your immune system weaker, which can lead to other underlying medical conditions that can further aggravate hair loss. They can also cause hormonal imbalance that affects the hair growth cycle (forcing the hairs that should still be growing to enter the resting phase prematurely) causing more hair shedding than normal.



There are three possible reasons why you can experience hair loss as you grow older. Here they are:

1. As you age, your hair stays in the Telogen phase (the last stage of the hair cycle where hair is resting and would eventually fall off) at a longer period of time than what the normal cycle requires. This means that you will be shedding more hair than usual and that growing a replacement for lost hairs will be slower.

2. Your estrogen levels will gradually decrease starting on your late 20s or early 30s. Since the body has to cope with this change, your hair follicles will produce thinner and sparser hairs.

3. Your scalp’s sebaceous glands will produce less and less sebum as you grow older. Sebum is essential in keeping hair healthy and strong. It is a natural oil that nourishes hair starting from the root down to the shaft. When you do not have enough sebum to nourish your hairs, they will get dry, brittle, and unhealthy — causing more hair falls.


Nutritional Deficiencies

Certain vitamins are crucial to keep hair and follicles healthy. If a person is lacking essential vitamins in the body, especially those playing a huge part in hair growth, (s)he will most likely experience hair loss. In a lot of cases too, deficiency in vitamins is a precursor to having medical conditions that cause hair loss. Below are the vitamins that are especially important in preventing and treating hair loss:


Zinc is important for keeping a balanced level of hormones in the body. As mentioned earlier, hormonal imbalance can cause hair loss. With hypozincemia (zinc deficiency), hair follicles would not be able to function well, causing them to produce unhealthy hair. Sometimes, they wouldn’t be able to produce any hair at all.

Vitamin A

To create sebum, sebaceous glands need Vitamin A. Previously, we discussed how sebum is essential in healthy hair growth as it acts as a natural conditioner. Without it, hair strands will become, dry, brittle, and weak — leading to more hair breakage and loss.

Vitamin B3 (Niacin)

Niacin helps in blood circulation, including in the scalp. It is important for the scalp to have a good circulation of blood to maintain proper hair nourishment.

Vitamin B6 (Pyridoxine)

Since Pyridoxine aids in cell-building and blood circulation, it is a key vitamin in stimulating hair growth. A deficiency of this vitamin (associated with microcytic anemia) will cause hair loss.

Vitamin C (Ascorbic Acid)

Vitamin C is one of the nutrients utilized in the production of red blood cells (which is a source of nourishment for hair). It is also an essential vitamin for building collagen, a kind of protein that is important for hair growth. Vitamin C also helps in better iron absorption, which makes hair healthy and strong.

Vitamin E

Like Vitamin B3 and B6, Vitamin E is needed to have a healthy circulation of blood all over the body, including in the scalp. As long as there’s good blood circulation, follicles will stay nourished and healthy.


Biotin, which is a kind of B-vitamin, is needed for cellular growth and for the production of amino acids — both of which are essential for healthy hair growth. It stimulates hair development, thickens the hair strands, and reduces hair loss. Although it can be found in natural food, it’s usually present in small amounts. The body can easily be deficient of this when one goes through high stress levels, intense exercise/physical activities, and long hours of work.


Inositol, another kind of B-vitamin, is a vital component of structural lipids that help in strengthening hair follicles. It also keeps the hair cell membranes healthy. Clinical studies that explored on the effects of B-vitamins (including inositol) in the body, showed that dramatic hair loss was experienced by people who were deficient of this vitamin.


Now that we have discussed the different causes of hair loss, we can proceed to identifying the different Types of Hair Loss and which of the causes above lead to each type.