Hair loss in women: assessing the causes and understanding test values

What to expect in this article

1. What normal hair loss is—and when it becomes noticeable
2. The three causal pathways compared directly
3. Iron status—and what is disputed about it
4. The thyroid and the documented laboratory recommendation
5. Genetic predisposition and its pattern
6. What a hormone panel cannot do
7. Triggers with a time delay
8. Warning signs: when it should be evaluated by a dermatologist
9. Is a blood test useful in your case?
10. How to have the values mentioned tested
11. What a blood test cannot answer about hair loss
12. What ultimately matters
Frequently asked questions
Sources

What normal hair loss is—and when it becomes noticeable

“A little hair loss is normal” is true, but not helpful unless someone says where “a little” ends. The Institute for Quality and Efficiency in Health Care gives a figure: healthy people lose about 70 to 100 hairs a day (IQWiG, as of 01/02/2023).

The second figure from the same source explains why this goes unnoticed: “At any given time, about 90 percent of all a person’s hair is in the growth phase.” Because new hair is growing back at the same time, the loss is offset.

Why a trigger becomes visible only later

An event that sends many hairs from the growth phase into the resting phase at the same time does not become apparent immediately. How long it takes can be inferred from two documented figures. The transitional phase between growth and rest lasts 2 to 4 weeks (IQWiG, as of 02.01.2023). In hair loss after childbirth, 2 to 4 months elapse between the event and the hair loss (Wolff et al., Deutsches Ärzteblatt International 2016). Both figures describe different processes, and the sources reviewed do not provide a general time range for every trigger.

In practical terms, this means that hair in the brush is not a finding. It becomes a clue when the pattern persists for weeks, the hair becomes thinner, or the scalp shows through in places where it did not before.

The three causal strands in direct comparison

The three causal strands differ in what underlies them. But they also differ in how well the relationship is actually substantiated, and that is the point that is usually overlooked in advisory texts. The table compares them along the same four criteria. The third row is the uncomfortable one: It does not say what is assumed, but what the sources reviewed actually support.

Two of the three columns have no entry in the first row. This is not an oversight: The sources reviewed do not describe a distinct hair pattern for iron or the thyroid. Only genetic predisposition has a pattern description, and even that comes from a source discussing men.

Iron status—and what is disputed about it

“Hair loss? You should get your iron levels checked” is something many women hear repeatedly before questioning the statement. It contains two claims that do not mean the same thing.

The first is supported by evidence. Ferritin, the laboratory value for iron stores, is part of laboratory diagnostics when the cause is unclear. This is stated by Wolff, Fischer, and Blume-Peytavi in Deutsches Ärzteblatt International (2016).

The second is not supported by evidence. The fact that a low ferritin level is the reason for hair loss does not follow from this. Almohanna and colleagues stated in Dermatology and Therapy (2019) that the relationship between hair loss and low serum ferritin has been debated for many years. Debated means: unresolved. And in its derivation of iron reference values (2023, published in 2024), the German Nutrition Society lists physical performance, thermoregulation, susceptibility to infections, and anemia as consequences of iron deficiency. Hair does not appear in this list.

Why the difference matters in practice

“Ferritin is part of the evaluation” means that the level is measured to investigate one possible explanation and rule out others. “Iron deficiency is the cause” means that if the level is low, the question has been answered. The second interpretation ends the search too soon.

For the same reason, this article does not provide target ferritin levels. The figures in circulation are recommendations from individual groups of authors, not a professional consensus. A number that looks like a threshold but is not one can do more harm than no number at all.

Here, the iron thread is organized only far enough for you to recognize whether it is yours. The details are covered elsewhere: Iron deficiency and diffuse hair loss examines the thread in detail, including laboratory values and progression.

The thyroid and the documented laboratory recommendation

This thread is most often overlooked because its symptoms seem harmless when considered individually. In countries such as Germany, approximately 5 in 100 people have an underactive thyroid, with women and older people particularly often affected (IQWiG, as of April 24, 2024). Dry hair and hair loss are included in the list of symptoms, alongside fatigue, feeling cold, dry skin, and weight changes.

The same source makes the limitation clear: the symptoms are nonspecific. None of these signs by itself indicates an underactive thyroid; the diagnosis is made through blood tests. An elevated TSH level may be an indication, but nothing more.

The most practically useful point is this: this thread rarely occurs alone. If hair loss is the only item on your list, there is little to suggest the thyroid. If months of fatigue that sleep does not relieve appear alongside it, the combination points in that direction.

Effluvium is the medical term for increased daily hair loss. Two aspects of this sentence carry more weight than they may seem to when reading it. It says “to rule out,” not “to detect”: The values are not measured to identify the cause, but to eliminate possible causes. An unremarkable result makes the list shorter.

And there is a syphilis test listed there. This line is regularly cut because it does not fit the picture. That is precisely why it remains here: It shows how broad the diagnostic workup is. A laboratory result does not answer a question here; it rules out possibilities.

The predisposition and its pattern

The third strand is the most common and the one for which a blood test contributes the least. The Federal Ministry of Health describes pattern hair loss as the most common form overall; it affects both men and women, but men much more frequently.

Here, attribution is necessary, though it is rarely provided. The article from which this information is taken concerns male pattern hair loss (gesund.bund.de, updated 05 November 2025). It draws a distinction itself: the course in women differs from this. There is no separate official page there on female pattern hair loss. The statement “up to 70 percent of men and 40 percent of women” also appears in this article about men. It can be cited, but it is not an independent official statement about women, and this article does not present it as one.

The pattern can be adopted directly without taking a detour: While women typically retain their frontal hairline and gradually lose hair in all directions from the center of the scalp, men typically develop a receding hairline at the temples. This is the most practically useful distinction in this article because it does not require laboratory testing. The actual classification is made in a dermatology practice.

A laboratory result does not change this assessment—not because it would be incorrect, but because it does not contribute to answering this question. Anyone who tests anyway gets numbers, but no answer.

What hormone testing cannot do

Sooner or later, the term hormone status comes up. The expectation behind it is understandable: Hair loss is considered a hormonal issue, so hormone testing should show what is going on. The evidence does not support this expectation.

The simplest test is the laboratory recommendation from the previous chapter. It lists ferritin, TSH, T3, T4, and a syphilis test. It does not mention a hormone panel, and the list above is reproduced in full.

Checked against the evidence

The second line has a consequence that causes more trouble in everyday life than the lack of benefit. Anyone who takes a high-dose hair supplement and then has blood values measured may distort precisely the figures they are testing.

The conclusion from this chapter is uncomfortable but brief: Testing hormone levels without a specific indication generally does not help with hair loss. Neither does taking a preparation without a specific indication, and it may interfere with the test that could provide useful information.

Triggers with a time lag

Two situations cause increased hair loss in women without anything being wrong. Both are textbook examples of the delay described in the first chapter.

The first case is the period after childbirth. Wolff, Fischer, and Blume-Peytavi describe postpartum effluvium as physiological—that is, a process that is part of the normal course and passes. The timing is decisive: Shortly after childbirth, birth-related stress and hormonal changes cause many hairs to enter the resting phase at the same time and fall out 2 to 4 months later (Deutsches Ärzteblatt International 2016).

The second case is starting or stopping hormonal contraceptives. The same paper notes that women should be asked about gynecological factors such as starting or stopping hormonal contraceptives. Here too, a change that occurred months ago can easily be overlooked as an explanation.

Before testing, therefore, review the last six months, not the last six weeks. If that period includes giving birth or changing your contraceptive method, bring it up yourself during the doctor’s appointment. It is not always asked about.

Four figures for context

Warning signs: when dermatological evaluation is needed

So far, this has concerned hair loss where sorting through the possibilities is helpful. There are situations in which that is the wrong approach because the evaluation belongs not in the laboratory but in a dermatology practice.

The first point concerns the scalp. Wolff, Fischer, and Blume-Peytavi note: “Attention should be paid to inflammatory redness and scaling, as psoriasis and eczema can lead to effluvium.” (Deutsches Ärzteblatt International 2016). A reddened or irritated scalp is a finding in its own right that a ferritin level does not explain.

The second point carries more weight. The same paper states: “Scarring or atrophic alopecias are a heterogeneous group of diseases that lead to the irreversible destruction of hair follicles.” Irreversible means that what is lost does not come back. Because diagnosis can be difficult in the early stages, waiting is the worst option when there are sharply defined or smooth-looking areas.

The German Federal Ministry of Health describes the process without dramatizing it: “If another cause is suspected, doctors initiate targeted examinations such as blood and hormone tests.” (gesund.bund.de, 05.11.2025). First the suspicion, then the targeted examination.

Editorial addition, without claiming a source: Hair loss that starts suddenly and changes significantly within a few weeks should also be assessed by a doctor rather than observed for months. The sources reviewed contain no citable statement for this assessment. It is included here as an editorial recommendation, not as evidence.

Is a blood test appropriate in your case?

A blood test is not a standard step for hair loss, but one that fits certain starting points and not others. The comparison covers both, including cases where testing is of no benefit.

How to have the listed values tested

Every general practitioner’s office can test ferritin and thyroid values. If you can take this route, it is best to do so there, because the results and consultation are handled together. A self-test is the alternative if this is not possible at short notice or if you want a baseline before your appointment.

A test by mybody®x (MYBODY Lab GmbH) covers both options. You collect the sample at home using a finger prick.

Capillary blood test

Women’s Wellness Check | Women’s Health Test

18 values from one blood sample, including ferritin and the complete thyroid profile consisting of TSH, fT3, and fT4, plus vitamin B12, vitamin D3, and the key organ values. What the test does not do: It measures ferritin and thyroid values, but it does not say why someone is losing hair. It does not include cycle hormones, and interpreting the findings remains a medical task.

Price €169.00 As of 30 August 2026; subject to change

Sample type Capillary blood

Processing time Kit shipping 1–3 business days
Laboratory analysis 3–5 business days after receipt of your sample central specification for blood tests, as of 4 August 2026

Laboratory Specialist laboratory in Germany
Product page information, accessed 30 August 2026

Go to the Women’s Health Test

Whichever route you choose, take the result to a discussion with a doctor. Numbers are not an interpretation, let alone a diagnosis.

What a blood test does not answer about hair loss

The most honest statement about blood values in hair loss is already in the cited source: They are used for exclusion. Here, a lab value works backward, ruling out possibilities instead of identifying a cause.

This leads to three limitations. An unremarkable result does not answer the question; it narrows it. If ferritin and thyroid values are unremarkable, the hair loss remains, but there are two fewer explanations to consider.

Conversely, an abnormal finding does not prove a connection. A low ferritin level in someone with existing hair loss means that two things are present at the same time, not that one causes the other. This confusion is why the discussion about iron and hair has remained open for years (Almohanna et al., Dermatology and Therapy 2019).

And the most common strand contributes nothing to laboratory testing. In hereditary hair loss, classification is based on the pattern and progression. Anyone who measures here is collecting numbers where the question needs to be framed differently.

If your nails have also become brittle or your skin has changed, Skin, hair, nails and blood values considers the three tissues side by side. This article deliberately focuses on just one.

What matters in the end

If you take away just one action from this article, let it be this: Write down when you first noticed it and what happened in the six months beforehand. A birth is relevant, as is starting or stopping hormonal contraceptives. Also note whether anything besides your hair is different from before.

Also take a look in the mirror: Is the hairline intact, and is the hair thinning at the crown? This takes five minutes and shows whether the third strand is even relevant. A medical practice will assess this, but you can write it down yourself.

It all began with the question of when hair loss becomes noticeable. The more useful question is which of the three strands is meant. With these notes, a doctor’s appointment is a different kind of appointment. Without them, you simply talk about hair in the brush.

Frequently asked questions

Sources

1. Wolff H, Fischer TW, Blume-Peytavi U: Diagnosis and treatment of hair and scalp disorders. Deutsches Ärzteblatt International 2016; 113(21): 377–86 – aerzteblatt.de
2. Federal Ministry of Health: Genetic hair loss in men (androgenetic alopecia), updated 5 November 2025 – gesund.bund.de
3. Institute for Quality and Efficiency in Health Care (IQWiG): Hypothyroidism, as of 24 April 2024, and How is hair structured and how does it grow?, as of 2 January 2023 – gesundheitsinformation.de
4. van Zuuren EJ, Fedorowicz Z, Schoones J: Interventions for female pattern hair loss. Cochrane Database of Systematic Reviews 2016 – cochrane.org

The verbatim quotation on laboratory diagnostics, the information on postpartum effluvium, the reference to hormonal contraceptives, scarring alopecias, and the scalp findings are taken from [1]. The frequency, patterns in women and men, the description of follicular hypersensitivity, and the differentiation from other causes are taken from [2], an article that explicitly addresses hair loss in men. The prevalence of hypothyroidism, hair loss as a listed symptom, TSH as a diagnostic pathway, and the figures on the hair cycle are taken from [3]. The assessment of the evidence on efficacy is based on [4]. The information on the iron debate and the effect of high biotin intake on laboratory results is attributed in the text to the authors, specialist journal, and year (Almohanna HM, Ahmed AA, Tsatalis JP, Tosti A, Dermatology and Therapy 2019); the consequences of iron deficiency are cited by the German Nutrition Society in its derivation of the reference values for iron (2023, published 2024). Information on price, biomarkers, sample type, and laboratory comes from the mybody®x product page, accessed on 30 August 2026. The processing times do not come from the product page but from the central specification of the blog system for blood tests, as of 4 August 2026; shipping time and analysis time are listed separately there. All sources were accessed and reviewed on 29 August 2026.

mybody®x Editorial & Specialist Team

Laboratory diagnostics Blood analysis interpretation Nutritional science Women's health

This article was produced by the mybody®x editorial and specialist team. The team combines laboratory diagnostics, nutritional science, and the interpretation of blood analyses. The people who contribute to it are listed on the authors page.

Published on 30 August 2026 · Last updated on 30 August 2026

The content is for general information purposes and does not replace medical advice, diagnosis, or treatment. Reference ranges depend on the laboratory, method, and age; the information on your test report is always authoritative.