💇♀️ Hair Falling Out in Clumps? These Lab Tests Can Reveal the True Cause
You run your hand through your hair, and a distressing clump comes out. You see a startling amount in your brush or the shower drain. It’s an alarming experience, but before you panic, it’s important to understand what’s happening.
Your hair is a sensitive barometer of your internal health. When it starts shedding excessively, it’s not the disease itself, but a signal. Your job is to decode that signal, not with miracle shampoos, but with objective data from lab tests.
Iron Deficiency: The Invisible Enemy of Your Hair
The short answer: More often than not, excessive hair shedding is linked to a deficiency in your body’s iron stores. The key marker here is not hemoglobin, but ferritin. This protein acts as your body’s iron warehouse. When your reserves are low, your body starts cutting back on “non-essential” functions, and hair growth is one of the first to go.
Why ferritin drops:
- Inadequate Intake: A diet low in red meat or other sources of highly absorbable heme iron is a primary culprit.
- Chronic Blood Loss: For women, heavy menstrual periods are a major and often overlooked cause of iron depletion.
- Poor Absorption: You can eat all the steak you want, but if you have gut issues like celiac disease or low stomach acid, you won’t absorb the iron effectively.
- Increased Demand: Pregnancy, intense athletic training, and periods of rapid growth all increase the body’s demand for iron.
What to look for: Lab reference ranges for ferritin are notoriously wide. For hair health, “normal” isn’t good enough; you need “optimal.”
- Red Flag: A ferritin level below 30 ng/mL is a major deficit that will almost certainly impact your hair.
- Optimal for Hair Health: Most trichologists and functional medicine doctors aim for a ferritin level of at least 50-70 ng/mL.
Thyroid Hormones: When the Conductor is Out of Tune
The short answer: Your thyroid gland is the master conductor of your metabolism. When it’s underactive (hypothyroidism), every process in your body slows down, including the hair growth cycle. Hair becomes dry, brittle, and sheds diffusely from all over the scalp.
Why the thyroid slows down: The most common cause is Hashimoto’s disease, an autoimmune condition where the immune system attacks the thyroid. Other causes include iodine deficiency and postpartum thyroiditis.
What to look for: The primary screening test is TSH (Thyroid-Stimulating Hormone). When the thyroid is sluggish, the brain’s pituitary gland “shouts” at it by releasing more TSH.
- Consult an Endocrinologist: A TSH level above 4.0 mIU/L warrants a medical evaluation. Many doctors consider a TSH above 2.5 mIU/L to be suboptimal, especially if you have symptoms like fatigue, weight gain, and hair loss.
Stress Hormones: The Cortisol Connection
The short answer: Chronic stress, whether physical or emotional, leads to prolonged high levels of the hormone cortisol. This shifts your body into “survival mode,” and “luxury” functions like robust hair growth are put on hold. The result, typically 2-4 months after a major stressor, is a massive shedding event called telogen effluvium.
What triggers it?
- Emotional Stress: Divorce, job loss, grief.
- Physical Stress: Major illness (especially with a high fever, like COVID-19), surgery, childbirth.
- Lifestyle Stress: Chronic sleep deprivation, over-training, or crash dieting.
Sex Hormones: The Androgenetic Factor
This is a different type of hair loss, known as androgenetic alopecia or pattern hair loss. Instead of diffuse shedding, you see thinning at the part line and crown. It’s caused by a genetic sensitivity of the hair follicles to male hormones (androgens).
When to check: If your hair loss fits this pattern, and especially if you have other signs of hormonal imbalance like acne or irregular periods, a hormonal workup is necessary.
Your Action Plan for Hair Loss
- Don’t Panic. Stressing about hair loss will only make it worse. Most cases are reversible once the underlying cause is addressed.
- Start with a Basic Lab Panel. The most informative initial tests are:
- Complete Blood Count (CBC)
- Ferritin
- TSH
- See a Doctor. Start with your primary care physician. They can interpret your initial results and refer you to the right specialist, whether it’s an endocrinologist, gynecologist, or dermatologist.
- Be Patient. Hair growth is a slow process. It can take 3-6 months after correcting an underlying issue to see a noticeable improvement in shedding and new growth.
