Quick summary: Hair Loss What Tests Should You Do
- Hair loss can have many causes, ranging from vitamin deficiencies to hormonal imbalances.
- Basic diagnostics include a complete blood count, ferritin, thyroid hormones, and vitamin levels.
- If needed, a doctor may order additional hormonal, microbiological tests, or trichoscopy.
- Early identification of the cause increases the chances of effective treatment and hair regrowth.
Spis treści
Hair loss is a problem that affects both women and men of all ages. The causes are diverse — from temporary conditions (such as telogen effluvium after stress or illness), through hormonal disorders and nutritional deficiencies, to dermatological and autoimmune diseases. In order to correctly identify the cause and plan effective treatment, appropriate diagnostic tests are often necessary. In this article, we explain which tests are most commonly recommended, when to perform them, and what the results may indicate.
When should you see a doctor and get tested?
If you notice excessive thinning of hair, sudden increased shedding (for example, losing hair in handfuls), general weakness, symptoms suggesting hormonal imbalance (such as sudden weight gain or menstrual irregularities), or visible skin changes on the scalp, you should consult a general practitioner, dermatologist, or trichologist. Based on a detailed medical interview and physical examination, the doctor will decide which tests are most appropriate.
Basic blood tests — what doctors usually order
Below is a list of tests most commonly recommended at the initial stage of hair loss diagnostics:
- Complete blood count (CBC) — helps detect anemia, which is frequently associated with increased hair loss.
- Iron and ferritin levels — ferritin, which reflects iron stores in the body, plays a crucial role. Low ferritin levels are commonly linked to telogen effluvium and weakened hair structure.
- Thyroid function tests (TSH, fT3, fT4, sometimes anti-TPO antibodies) — both hypothyroidism and hyperthyroidism can lead to hair loss. Thyroid tests are among the first investigations to consider.
- Vitamin D, vitamin B12, and folic acid — deficiencies in vitamins and micronutrients may contribute to excessive hair shedding. Growing evidence suggests a link between low vitamin D levels and certain types of hair loss.
- Hormonal profile (especially in women or when androgen-related disorders are suspected) — tests such as total testosterone, free androgen index, DHEA-S, and SHBG are useful when symptoms of androgen excess are present (e.g., hirsutism, acne, irregular menstrual cycles).
Additional tests — depending on clinical presentation
- Cortisol levels — recommended when chronic stress or disorders of the adrenal glands are suspected.
- Microbiological tests (swabs, cultures, mycological examination) — useful if inflammatory lesions, scaling, pustules, or suspected fungal infection of the scalp are present.
- Zinc, selenium, and copper levels — may be considered in selected cases, especially in patients with long-term hair loss or dietary deficiencies, although scientific evidence is mixed.
Specialist examinations performed by a dermatologist or trichologist
- Trichoscopy — a non-invasive dermatoscopic examination of the scalp that allows assessment of hair follicles and characteristic features of different types of alopecia. It is particularly helpful in differentiating androgenetic alopecia, telogen effluvium, and alopecia areata.
- Scalp biopsy (histopathological examination) — performed when clinical evaluation and trichoscopy do not provide a clear diagnosis, especially when scarring alopecia or inflammatory conditions are suspected. A biopsy helps determine whether permanent damage to hair follicles has occurred.
How to prepare for tests
Most blood tests are performed in the morning, often on an empty stomach — especially when metabolic parameters are assessed. However, tests such as ferritin, TSH, or vitamin levels do not always require fasting. If hormonal tests are ordered, women should ask about the optimal day of the menstrual cycle for testing, as some hormones are cycle-dependent. Always inform your doctor about medications and supplements you are taking, as some may influence test results.
Understanding the results — key indicators
- Low ferritin levels — may indicate iron deficiency; in many patients, iron supplementation improves hair density and quality.
- Abnormal TSH or fT4 values — suggest thyroid disorders; appropriate treatment often reduces hair shedding.
- Abnormal androgen levels — may prompt further evaluation for conditions such as polycystic ovary syndrome (PCOS) and require consultation with an endocrinologist or gynecologist.
When is specialist consultation necessary?
If basic tests do not identify the cause, hair loss continues to worsen, or systemic symptoms appear, referral to a dermatologist or trichologist is recommended. In cases involving hormonal or hematological abnormalities, cooperation with an endocrinologist or internist may be necessary.
Summary
The diagnostic process for hair loss begins with a thorough medical history and basic blood tests — complete blood count, ferritin, thyroid function tests, and vitamin levels are among the most commonly ordered. Depending on the clinical picture, diagnostics may be expanded to include hormonal testing, microbiological examinations, trichoscopy, or scalp biopsy. Early identification of the underlying cause significantly increases the chances of effective treatment and hair regrowth. If you are unsure which tests are appropriate, consult a general practitioner or dermatologist.
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