Hair Loss: Do You Need Blood Tests?

Let’s answer the main question first: most often, no. Not everyone with hair loss needs to undergo a large number of tests.

Which investigations are actually needed and when they should be performed depends primarily on the type of hair loss and accompanying symptoms.

How Much Hair Loss Is Normal Per Day?

Hair is constantly renewing itself: some hairs are growing, others are in a resting phase, and some fall out so that new hairs can grow in their place.

Losing approximately 50–100 hairs per day is considered normal.

You should consult a doctor if you notice that:

• there is significantly more hair than usual on your brush, pillow, or in the shower;
• your hair has become noticeably thinner;
• your scalp has become more visible through the hair;
• bald patches have appeared.

1. Telogen Effluvium

Telogen effluvium usually occurs after a certain type of “stress” to the body. Hair loss is generally diffuse, affecting the entire scalp, rather than occurring in separate patches.

Possible triggers include:

• childbirth;
• an illness, especially one accompanied by a high fever;
• surgery;
• severe emotional stress;
• strict diets and significant weight loss;
• certain medications.

When Does Hair Loss Start?

An important point: hair loss usually begins not immediately after the triggering event, but approximately 2–3 months later.

As a result, people often do not connect their hair loss with an illness, stressful event, childbirth, or weight loss that occurred several months earlier.

After the underlying cause is addressed, hair shedding usually gradually decreases. Restoration of hair density may take 6–12 months.

If significant hair shedding continues for more than 6 months, the situation should be reassessed to exclude other causes, including chronic telogen effluvium and other forms of alopecia.

Which Tests May Be Needed?

When telogen effluvium is suspected, a doctor may recommend:

• TSH — to assess thyroid function;
• complete blood count (CBC) and hemoglobin — to assess for anemia;
• ferritin — to assess iron stores.

Additional tests may be recommended depending on other symptoms and the individual clinical situation.

2. Androgenetic Alopecia

The pattern of hair loss is different in androgenetic alopecia.

In men, it typically presents with:

• a receding hairline at the temples;
• thinning at the crown;
• gradual reduction in overall hair density.

When the clinical presentation is typical, hormonal testing is usually not necessary in men. The diagnosis is generally made based on the examination and characteristic pattern of hair loss.

In women, androgenetic alopecia more often presents as gradual thinning at the crown and widening of the central part.

Hormone levels may remain normal.

When Do Women Need Hormonal Tests?

Hormonal evaluation may be appropriate if hair loss is accompanied by signs of hyperandrogenism, such as:

• irregular menstrual cycles;
• increased hair growth on the face or body (hirsutism);
• other signs of androgen excess.

One possible cause of these symptoms is polycystic ovary syndrome (PCOS).

Depending on the clinical situation, a doctor may recommend tests such as total testosterone and DHEA-S.

How Is Androgenetic Alopecia Treated?

Treatment depends on sex, age, the underlying cause, and any accompanying medical conditions.

Treatments with evidence of effectiveness include:

• minoxidil — may be used in both men and women;
• finasteride — used primarily in men;
• in women with hyperandrogenism, a doctor may consider combined oral contraceptives (COCs) or other anti-androgen medications, when clinically indicated.

What Is Important to Know About Treatment?

Treatment of alopecia takes time.

• The first noticeable results are usually assessed after 3–6 months.
• Hair shedding may temporarily increase during the early stages of treatment in some patients.
• Treatment often needs to be continued long-term to maintain the results.
• After treatment is discontinued, the achieved effect may gradually be lost.

Can Vitamins and Supplements Help With Hair Loss?

“Hair vitamins,” biotin, collagen, and various hair-growth supplements are often perceived as an easy way to restore hair density.

However, if a person does not have a confirmed deficiency, there is insufficient evidence that these supplements prevent or treat hair loss.

Therefore, taking large amounts of vitamins and supplements “just in case” is generally not recommended.

It is particularly important to be aware of biotin. It is found in many hair supplements and can significantly interfere with certain laboratory tests, including TSH and other hormone tests.

Supplements are also not completely risk-free. Their composition and dosages may vary, and some supplements or high doses of certain substances can cause adverse effects, including drug-induced liver injury.

Therefore, when experiencing hair loss, it is better to first determine its cause and then decide whether any vitamins or supplements are actually needed.