When clients come to see me about hair loss or excessive shedding, one of the first things I explain is this: hair loss is very often a symptom—not the actual problem.
Your hair is incredibly sensitive to what is happening internally. Hormonal changes, nutrient deficiencies, stress, inflammation, medication, thyroid imbalance, and even digestive issues can all show up in the hair before they appear elsewhere.
This is why blood tests for hair loss can be such an important part of a thorough hair loss investigation. They can help identify potential underlying causes and allow treatment to focus on addressing the root of the problem, rather than simply masking the symptoms.
As a Trichologist, I’m not simply looking at whether your blood work falls within a laboratory “normal” range. I’m looking at whether your results are optimal for healthy hair growth.
Hair is considered a non-essential tissue by the body. If nutrients are low, hormones fluctuate, inflammation is present or the body is under physical or emotional stress, your hair is often one of the first areas to be affected.
Blood tests help uncover what may be happening beneath the surface and can identify underlying factors that contribute to hair thinning and excessive shedding.
Blood tests may help identify:
Without investigating these areas, many people spend money on shampoos, supplements or treatments that never address the underlying cause of their hair loss.
Blood tests are an important part of investigating hair loss, but they don’t always provide the complete answer.
Some forms of hair loss are directly linked to nutritional deficiencies, hormone imbalances or underlying medical conditions that can be detected through blood testing. Others require a detailed scalp examination, trichoscopy, medical history and clinical assessment before an accurate diagnosis can be made.
Blood tests should always be considered as one piece of the overall diagnostic process rather than a standalone answer.
This is something I hear all the time.
The truth is that “normal” does not always mean optimal for healthy hair growth.
Laboratory reference ranges are designed to identify disease or significant medical abnormalities. Hair follicles, however, are highly sensitive and often respond to subtle nutritional deficiencies or hormonal changes long before blood results fall outside the laboratory range.
For example, ferritin levels may technically sit within the laboratory reference range but still be too low to adequately support healthy hair growth.
This is where a trichology-focused interpretation of blood results can provide valuable insight.
Every client is different, and blood testing should always be tailored to the individual. However, there are several blood markers that are commonly assessed when investigating hair thinning or excessive shedding.
Ferritin is one of the most important blood tests for hair loss because it measures your body’s stored iron.
Low ferritin levels are commonly associated with chronic diffuse hair thinning and excessive shedding, particularly in women. Even mild iron depletion may interfere with the normal hair growth cycle.
Iron studies commonly include:
Low ferritin remains one of the most common findings seen during hair loss investigations.
Your thyroid plays a significant role in regulating the hair growth cycle.
Both underactive and overactive thyroid disorders may contribute to excessive shedding, brittle hair, texture changes and diffuse thinning.
Common thyroid blood tests include:
In some cases, thyroid antibodies may become elevated long before thyroid disease is formally diagnosed.
Vitamin D deficiency is extremely common in the UK and may contribute to hair shedding, poor scalp health, fatigue and low mood.
Low vitamin D levels are frequently identified in people experiencing telogen effluvium and female pattern hair loss.
Vitamin B12 and folate are essential for healthy red blood cell production and oxygen delivery throughout the body.
Deficiencies may contribute to fatigue, poor hair quality and increased shedding.
Vegetarians, vegans, individuals with digestive disorders and those taking certain medications may be at greater risk of deficiency.
Hormonal changes frequently contribute to hair loss, particularly during:
Hormonal blood tests may include:
Hormonal hair loss does not always mean hormone levels are elevated. In many cases, hair follicles are simply more sensitive to normal hormonal fluctuations.
A full blood count (FBC) provides useful information about overall health and may indicate anaemia, infection or immune system abnormalities.
Inflammatory markers such as CRP or ESR may also be useful where inflammatory scalp conditions or autoimmune disorders are suspected.
Depending on your symptoms and medical history, additional investigations may include:
Women experiencing hair thinning often benefit from assessing ferritin, thyroid function, vitamin D, vitamin B12, folate and hormone levels, particularly where hair loss is associated with heavy periods, menopause, PCOS or postpartum changes.
Identifying and correcting nutritional or hormonal imbalances can often form an important part of a comprehensive treatment plan.
Although male pattern hair loss is largely genetic, blood testing may still help identify contributing factors such as iron deficiency, thyroid disorders, vitamin D deficiency, inflammation or nutritional deficiencies that may worsen hair shedding.
Blood work is incredibly valuable, but it is only one part of a complete hair loss assessment.
A comprehensive trichology consultation should also include:
Two people can have identical blood test results and completely different causes of hair loss. That’s why a personalised assessment is so important.
To make the investigation process easier, blood testing can also be arranged directly through Fibre Trichology.
Options include:
These tests are designed to investigate possible underlying contributors to hair thinning, excessive shedding and scalp concerns.
You can find more information and book your tests through the Fibre Trichology website.
Absolutely.
Your GP can often arrange initial investigations, particularly if your hair loss is sudden, excessive or accompanied by symptoms such as fatigue, weight changes, menstrual irregularities or scalp discomfort.
If you’ve recently had blood tests performed, bring the results to your consultation. Reviewing them alongside your medical history and scalp examination often provides valuable clinical insight.
There is no single blood test that identifies every cause of hair loss. Ferritin, thyroid function, vitamin D and hormone testing are among the most commonly requested investigations.
Yes. Low ferritin is one of the most common nutritional factors associated with excessive hair shedding and chronic diffuse thinning, particularly in women.
Yes. Both underactive and overactive thyroid conditions can affect the normal hair growth cycle, leading to increased shedding and changes in hair texture.
Low vitamin D has been associated with several types of hair loss, including telogen effluvium and female pattern hair loss, although it is rarely the sole cause.
No. Blood tests provide valuable information but should always be interpreted alongside a detailed consultation, scalp examination and trichoscopic assessment.
Hair loss can feel overwhelming, but blood testing often provides important clues about what your body may be trying to tell us.
Healthy hair growth relies on much more than topical products alone. Understanding the underlying cause allows treatment to be tailored to both your hair and your overall health.
At Fibre Trichology, I take a holistic, evidence-based approach to investigating hair and scalp conditions because lasting results come from understanding why hair loss is happening in the first place.
