Blood Tests for Hair Loss
& Scalp Investigations
Hair loss can have several causes including inherited pattern thinning, underlying medical conditions and problems affecting the scalp.
Blood tests, scalp biopsies and skin samples can help investigate certain causes. However, not everyone experiencing hair loss needs these investigations. I assess the history and pattern of hair loss first. This helps determine whether further testing is appropriate.
The aim is to establish the likely cause before considering suitable treatments including PRP or hair transplantation.
DrThomas
BSc (Hons) MBBS MRCGP
FUE Hair Transplant Surgeon UK
Tests
Which Blood Tests Can Help Investigate Hair Loss?
Blood tests for hair loss can identify medical conditions or deficiencies that may contribute to excessive shedding or thinning. These include iron deficiency, anaemia and thyroid disorders. In some patients, nutritional deficiencies or hormonal conditions may also be relevant. However, there is no single blood test that can diagnose every cause of hair loss.
Male and female pattern hair loss can often be recognised through the medical history and examination without extensive laboratory investigations. Therefore, Dr Thomas uses targeted blood tests based on individual symptoms rather than recommending the same screening panel for everyone.
Which Blood Tests Might Be Recommended?
| Blood test | What it can help identify |
|---|---|
| FBC | Anaemia or abnormalities in blood cells |
| Ferritin | Reduced iron stores, including deficiency without anaemia |
| Thyroid function | Thyroid abnormalities that may contribute to shedding |
| B12 and folate | Deficiencies when dietary or medical factors suggest a risk |
| Vitamin D | Deficiency in patients where testing is clinically indicated |
| Hormone profile | Possible androgen excess or endocrine disorders when symptoms suggest them |
These are examples and not a standard panel required for every patient. For example, sudden widespread shedding after illness may warrant different investigations from gradual recession of the frontal hairline.
Hormone testing may be relevant when hair loss occurs alongside irregular periods, acne, excess facial hair or other endocrine symptoms.
The choice of tests should reflect the clinical findings.
How Can I Arrange Blood Tests for Hair Loss?
Following consultation, Dr Thomas and the team can advise which blood tests may be appropriate for investigating your hair loss. Patients arrange these through their own GP who will again need to check the indication for them.
Most laboratory blood tests involve taking a sample from a vein in the arm. Private at-home tests are also available but they are not suitable for every investigation.
Dr Thomas recommends choosing tests according to the suspected diagnosis rather than purchasing a full panel privately without a clear medical reason.
What If My Hair Loss Blood Tests Are Normal?
Normal blood results do not rule out hair loss or mean that no treatment options are available. Androgenetic alopecia, commonly known as pattern hair loss, frequently occurs without abnormalities in routine blood tests.
Equally, an abnormal blood result does not automatically explain the cause of thinning. The results should be considered alongside your history, scalp examination and pattern of hair loss.
Where appropriate, further assessment may help determine whether medical treatment or hair restoration could be beneficial.
Biopsy
When Is a Scalp Biopsy Needed for Hair Loss?
A scalp biopsy involves taking small tissue samples for examination under a microscope. It can help when the cause of hair loss remains unclear particularly if inflammation or scarring is suspected. Most patients with typical pattern hair loss do not need a scalp biopsy.
How Is a Scalp Biopsy Performed?
If a biopsy is recommended the procedure is booked at a separate clinic appointment.
Dr Thomas examines the scalp and select the most appropriate areas for sampling. After administering local anaesthetic, two small tissue samples are taken using a small punch instrument. The samples are sent to a laboratory for microscopic analysis.
The biopsy sites may require stitches and will leave small scars. Once the results are available Dr Thomas will discuss the findings and explain the next steps. Depending on the diagnosis we may recommend further assessment or treatment through dermatology.
What Can a Scalp Biopsy Diagnose?
A scalp biopsy can provide information about hair follicles, inflammatory changes and scarring. It may help investigate conditions such as lichen planopilaris, frontal fibrosing alopecia and other causes of unexplained hair loss. However a biopsy does not always provide a definitive diagnosis.
Sampling
Skin Scraping and Scalp Samples for Hair Loss
Scalp skin scrapings and hair samples can help investigate infections affecting the scalp. They may be appropriate when hair loss occurs alongside itching, scaling, inflammation or broken hairs. These investigations are particularly useful when a fungal infection is suspected.
How Is a Scalp Skin Scraping Performed?
Following a consultation the scalp sampling can be arranged at a separate appointment. Dr Thomas gently collects surface scales or affected hairs from the area requiring investigation.
The procedure is usually quick and does not require local anaesthetic. Samples are sent to a laboratory for microscopy and culture analysis.
When the results are available Dr Thomas will discuss the findings and advise on appropriate management. Depending on the diagnosis, further treatment through the patient’s GP or dermatologist may be recommended.
What Can Scalp Sampling Identify?
Scalp scrapings and hair samples can help identify fungal infections, including tinea capitis. Microscopy and culture may help detect the organism responsible and guide subsequent treatment.
Conditions like psoriasis, eczema and seborrhoeic dermatitis are generally diagnosed through clinical examination rather than routine scraping. Persistent inflammation, unexplained hair loss or suspected scarring may require a different investigation or specialist assessment.
What If My Hair Loss Blood Tests Are Normal?
Normal blood results do not rule out hair loss or mean that no treatment options are available. Androgenetic alopecia, commonly known as pattern hair loss, frequently occurs without abnormalities in routine blood tests.
Equally, an abnormal blood result does not automatically explain the cause of thinning. The results should be considered alongside your history, scalp examination and pattern of hair loss.
Where appropriate, further assessment may help determine whether medical treatment or hair restoration could be beneficial.
Assessment
Which Hair Loss Investigation Is Right for You?
The type of investigation depends on your symptoms, scalp examination and how your hair loss has developed.
For example, gradual hairline recession may suggest pattern hair loss without requiring blood tests or a biopsy. But sudden shedding may prompt consideration of medical conditions, nutritional factors or recent illness. Persistent redness, pain, scaling or unexplained patches of hair loss may require closer assessment of the scalp.
If further investigations are indicated Dr Thomas and the team will explain the available options and why they may be useful. These may include blood tests through your GP or scalp investigations arranged at a separate clinic appointment.
Patients can also pursue assessment through their GP or a dermatologist, privately or through the NHS. For further guidance, see my article on when dermatologists can help with hair loss.
Planning
What Treatments Are Available After Hair Loss Investigations?
Once the likely cause of hair loss is established the next step is deciding whether treatment is appropriate.
Some conditions require medical treatment before hair restoration can be considered. However, patients with pattern hair loss may benefit from treatments aimed at maintaining existing hair or improving coverage.
The most appropriate option depends on the diagnosis, stage of hair loss and long-term expectations.
Non-Surgical Hair Loss Treatments
Medical treatments such as minoxidil or finasteride may help manage certain forms of pattern hair loss.
Platelet-rich plasma (PRP) treatment may also be considered for suitable patients experiencing thinning.
Additionally, low level laser therapy for hair loss offers a home-use, non-medicated approach that may improve hair density in selected patients.
These treatments have different indications, benefits and limitations.
When Might a Hair Transplant Be Appropriate?
FUE hair transplantation may be appropriate for patients with established pattern hair loss and sufficient donor hair. However, surgery is not suitable for every patient.
Active inflammatory or scarring hair loss requires appropriate medical assessment and management before considering surgical restoration. Dr Thomas also considers future progression, existing hair density and long-term donor preservation when assessing transplant suitability.
If you’re considering a hair transplant, you can also try the suitability tool. It provides an initial guide to your options based on your hair loss pattern and other factors.
Started
Considering Hair Loss Investigations?
Understanding the cause of hair loss is an important step towards choosing the right treatment. Dr Thomas’s medical background and experience in hair restoration help inform this assessment.
During the consultation we will review your medical history, examine your scalp and discuss the progression of your hair loss.
If further investigation is indicated we can consider blood tests, scalp biopsy or skin sampling. Once we understand the likely cause we can discuss appropriate treatment, including PRP or FUE transplantation where suitable.
Questions
Hair Loss Tests FAQs
References
Primary Care Dermatology Society (2026) ‘Alopecia — an overview’. Available at: https://pcds.org.uk/clinical-guidance/alopecia-an-overview
British Association of Dermatologists (2025) ‘Telogen effluvium’. Available at: https://www.bad.org.uk/pils/telogen-effluvium/
National Institute for Health and Care Excellence (2019, updated) ‘Thyroid disease: assessment and management’, NG145. Available at: https://www.nice.org.uk/guidance/ng145
Fuller, L.C. et al. (2014) ‘British Association of Dermatologists’ guidelines for the management of tinea capitis 2014’, British Journal of Dermatology, 171(3), pp. 454–463. Available at: https://academic.oup.com/bjd/article/171/3/454/6615682
Dr Peter Thomas
MBBS MRCGP FUE Hair Transplant Surgeon
UK-trained doctor and specialist FUE hair transplant surgeon with postgraduate qualifications including MRCGP and specialist training to CCT level. Bringing refined FUE hair restoration techniques and renowned for natural results.