Hair loss: common causes and habits that help slow it down

Losing some hair every day is normal, but when shedding increases it is worth understanding why. Here are the most common causes, the habits that help and the signs that mean it is time to see a dermatologist.

Finding hair on your brush, on the pillow or in the shower drain happens to everyone. Hair renews itself constantly, and losing between 50 and 100 hairs a day is generally considered normal. The problem starts when that number rises clearly, when the hair looks thinner, or when patches of lower density begin to show.

Before jumping to quick fixes, it is worth understanding why hair falls out in the first place. Not all hair loss has the same cause, and what works for one case can do nothing at all for another.

How the hair growth cycle works

Every follicle goes through several phases that repeat throughout life:

• Growth phase (anagen): can last several years. Most of the hair on your head is in this phase at any given time.
• Transition phase (catagen): lasts a few weeks. The follicle shrinks and the hair stops growing.
• Resting and shedding phase (telogen): lasts a few months. At the end, the hair falls out and makes room for a new one.

When something disrupts this cycle, more hairs enter the shedding phase at the same time, or new hairs grow back thinner. That is the basis of almost every type of hair loss.

Most common causes of hair loss

Androgenetic alopecia

This is the most common cause in both men and women. It has a strong hereditary component and is linked to how sensitive the follicles are to certain hormones. In men it usually starts at the hairline and crown. In women it tends to show up as diffuse thinning on the top of the head, with a widening parting. It is progressive, so the sooner it is assessed, the more options there are to act on it.

Telogen effluvium

This is a diffuse, sometimes dramatic, hair loss that appears two or three months after a trigger: a high fever, surgery, giving birth, a very restrictive diet, a period of intense stress, or stopping certain contraceptives. It is alarming because hair comes out in handfuls, but it is usually temporary and hair tends to recover once the underlying cause goes away.

Nutritional deficiencies

The hair follicle is very active and needs energy and nutrients. Low iron, insufficient protein intake or very low-calorie diets can encourage hair loss. The role of vitamin D or zinc is also being studied. The sensible approach is to check this with a blood test rather than assume it.

Health conditions and medication

Thyroid disorders, some autoimmune diseases, scalp infections and certain medications can cause hair loss. In these cases hair loss is just one more symptom, and the important thing is to treat the underlying problem.

Alopecia areata

This shows up as rounded, well-defined bald patches that appear suddenly. It has an autoimmune origin and needs medical assessment.

Traction and external damage

Tight ponytails and braids, hair extensions, daily use of high-heat straighteners or repeated bleaching can damage the hair and, if the tension is kept up for years, the follicle too.

Habits that help take care of your hair

There is no single trick that works for everyone, but there are habits that support healthier hair and reduce some of the factors that make shedding worse:

• Eat a varied and sufficient diet. Include protein at main meals (eggs, legumes, fish, meat, dairy), along with fruit, vegetables and nuts.
• Avoid drastic diets. Losing a lot of weight in a short time is one of the typical triggers of telogen effluvium.
• Look after sleep and stress. Sleeping well, exercising and setting aside time to unwind helps the body in general, and hair benefits too.
• Cut back on heat. Use a hairdryer on a medium setting, apply heat protectant and do not use straighteners every day.
• Handle it gently. Detangle from the ends up to the roots, with hair slightly dry, and vary your hairstyle so you are not always pulling on the same area.
• Wash your hair as often as you need to. A clean scalp without excess oil or flaking is a good starting point.
• Protect yourself from the sun. A hat or cap in summer protects the scalp, especially if there are already areas of lower density.

Myths worth debunking

Plenty of ideas about hair loss circulate that simply do not hold up:

• "Washing it daily makes it fall out more." The hairs that come out in the shower were already in the shedding phase. Washing it just makes them come loose at that moment rather than another.
• "Cutting it makes it stronger." Trimming the ends improves the look of damaged hair, but it has no effect on the root.
• "Caps cause baldness." There is no reason to think so, unless they are tight enough to pull on the hair.
• "The more vitamins, the better." Supplements make sense when there is a deficiency or a specific need. Taking high doses without needing them brings no benefit, and in the case of biotin can even skew certain blood test results. If you take supplements, tell your doctor before having a blood test.

When to see a dermatologist

Hair loss has many causes, and getting the right diagnosis makes all the difference. Book an appointment if you notice any of the following:

• The shedding is sudden and heavy and lasts more than two or three months.
• Rounded bald patches or hairless areas appear.
• There is itching, pain, redness, flaking or sores on the scalp.
• The hair loss comes with tiredness, weight changes, sensitivity to cold or heat, or other general symptoms.
• In women, if it is linked to irregular periods, acne or increased hair growth on the face or body.
• Hair is visibly thinning at an early age.

A dermatologist may order a blood test, examine the scalp and, if needed, suggest treatments backed by science. In androgenetic alopecia, acting early is usually key to preserving the hair you still have.

Patience and consistency

Hair grows slowly, so any change in habits or treatment needs months before it shows. Be wary of products that promise results in a few days, and track changes with photos taken in the same light every so often, rather than counting hairs on the pillow.

In our hair care category you will find products designed to complement your hair routine. If you have any doubts about whether they are right for you, check with your pharmacist or doctor.