💇‍♀️ Female Hair Loss & Thinning

What this panel can settle, and by what logic

The order of these ten markers is the argument. A tertiary-center series of 155 women investigated for hair loss found nutrient deficiencies in 83.9%, iron deficiency specifically in 70.3%, autoimmune causes in 14.8%, psychological stress in 12.3% and thyroid disease in 7.7% Lin 2023. Androgenic loss is further down that list than the marketing suggests, and this panel is built in that order.

1. Ferritin with the Iron Panel (Iron, TIBC, Transferrin Saturation) is the first question, and the threshold is not the anemia one. In that series the ferritin corresponding to the anemia cut-off of 12.0 g/dL hemoglobin was 5.1 ng/mL, while the level the authors identified as adequate for hair growth was 40 to 60 ng/mL, corresponding to a hemoglobin of 13.1 to 13.8 g/dL Lin 2023. Those two numbers are an order of magnitude apart, which is exactly why a laboratory report can say ‘normal’ while a follicle is starving.
2. TSH (Thyroid-Stimulating Hormone) with Free T4 (Thyroxine) and Thyroid Antibodies (TPO + TgAb) is the second. Antibodies are on the list because autoimmune thyroid disease can shed hair before the TSH moves, which a TSH-only screen cannot show you.
3. Free Testosterone with SHBG (Sex Hormone-Binding Globulin) and DHEA-S is the third, deliberately. Low SHBG raises the free fraction without moving the total, and DHEA-S separates an adrenal contribution from an ovarian one. Reaching this question only after iron and thyroid is the correct sequence rather than a cost-saving one.
4. Zinc, Plasma and Vitamin D (25-Hydroxy) close the nutrient half, both correctable, both with awkward assays — zinc needs strict collection conditions Ceballos-Rasgado 2024 and 25-hydroxyvitamin D varies measurably between laboratories Wise 2021.

What it cannot settle, and what would

It cannot tell you which kind of hair loss you have. Distinguishing female pattern hair loss from telogen effluvium, alopecia areata and the scarring alopecias is done by looking: distribution, part width, pull test, trichoscopy and occasionally a scalp biopsy, inside a staged clinical algorithm Singh 2021. Those four have different treatments and different prognoses, and no combination of these ten results separates them.

It cannot predict whether minoxidil or an anti-androgen will work. Nothing here is a response marker. A normal androgen result does not rule out pattern loss, and a raised one does not guarantee that lowering it regrows anything — female androgen concentrations also sit where direct assays lose precision Casals 2023.

It cannot date the trigger, which is the question telogen effluvium turns on. Shedding follows the insult by 2 to 4 months, so the illness, surgery, birth or crash diet that caused it has usually resolved by the time the hair falls and by the time the blood is drawn. A calendar answers this; a panel does not.

And there is no hs-CRP on the list, so the most important number on it is unguarded. Ferritin rises with inflammation, which is what the BRINDA adjustment methods exist to correct Luo 2023. Read the transferrin saturation on the Iron Panel (Iron, TIBC, Transferrin Saturation) beside it, and treat a mid-range ferritin in someone recently unwell as unproven rather than reassuring Cancado 2025.

Draw conditions that decide whether the money is wasted

Of everybody in this cohort, the reader of this page is the most likely to be taking the one supplement that ruins the panel.

1. Stop biotin for 72 hours, and check the label of anything sold for hair, skin or nails. Those products commonly contain 5,000 to 10,000 mcg, and at those doses biotin distorts streptavidin-based immunoassays — here that is TSH (Thyroid-Stimulating Hormone), Free T4 (Thyroxine) and Thyroid Antibodies (TPO + TgAb), three of the ten Li 2020. A false Graves' pattern in a woman who came in about her hairline is the specific failure this instruction prevents.
2. No oral iron for 5 to 7 days before. Serum iron and transferrin saturation follow the last tablet; Ferritin does not, and ferritin is the number the 40 to 60 ng/mL target is written against Lin 2023.
3. Days 2 to 5 for the androgens if you are cycling, but do not delay the whole panel for it. The iron and thyroid half is where the treatable findings are, and postponing a ferritin by three weeks to align a free testosterone is a bad trade on this particular page Casals 2023.
4. Morning, fasted, clean draw for Zinc, Plasma. Zinc status assessment is sensitive to time of day, recent meals and hemolysis, which is why the methodological reviews specify the collection rather than just the interval Ceballos-Rasgado 2024.

How you would know it answered your question, and what each pattern means next

Five patterns. Every interval here is set by the hair cycle, which is slow and which is why so many people conclude a treatment failed.

• Ferritin under 40 ng/mL: treat it, and start early. In that series, disease duration predicted the ferritin response and beginning iron within 6 months of onset carried the better prognosis Lin 2023. Recheck ferritin at 12 weeks; judge the hair at 4 to 6 months, because a follicle re-entering anagen is not visible before that.
• Positive Thyroid Antibodies (TPO + TgAb) with a normal TSH (Thyroid-Stimulating Hormone): autoimmune thyroid disease in progress. Monitor TSH annually and do not attribute the shedding to it until the TSH actually moves.
• High Free Testosterone with a low SHBG (Sex Hormone-Binding Globulin) and raised DHEA-S: this is the androgenic picture, and it is worth checking for PCOS rather than treating the scalp alone. SHBG responds to metabolic change over 12 to 16 weeks, so that is the retest window.
• Low Zinc, Plasma or Vitamin D (25-Hydroxy): correct and recheck at 8 to 12 weeks, then stop — neither is a long-term hair supplement, and vitamin D results move between laboratories enough to make small changes uninterpretable Wise 2021.
• All ten normal: the panel did its job by clearing the reversible list. The next appointment is dermatological, with a trichoscope, because the remaining question is which pattern this is Singh 2021.

Sources read for these sections

• Lin CS, et al. Diagnosis and treatment of female alopecia: Focusing on the iron deficiency-related alopecia. Tzu Chi Medical Journal 2023 · PMID 38035053
• Singh M, Acharya A. Overview and Algorithmic Approach to Management of Male and Female Pattern Hair Loss. Indian Journal of Plastic Surgery 2021 · PMID 34984079
• Cancado RD. Defining Global Thresholds for Serum Ferritin: A Challenging Mission in Establishing the Iron Deficiency Diagnosis in This Era of Striving for Health Equity. Diagnostics (Basel) 2025 · PMID 39941219
• Luo H, et al. A Practical Guide to Adjust Micronutrient Biomarkers for Inflammation Using the BRINDA Method. Journal of Nutrition 2023 · PMID 36792034
• Ceballos-Rasgado M, et al. Methods of Assessment of Zinc Status in Humans: An Updated Review and Meta-analysis. Nutrition Reviews 2024 · PMID 38917458
• Wise SA, et al. Vitamin D Standardization Program (VDSP) intralaboratory study for the assessment of 25-hydroxyvitamin D assay variability and bias. Journal of Steroid Biochemistry and Molecular Biology 2021 · PMID 34010687
• Casals G, et al. Recommendations for the measurement of sexual steroids in clinical practice. A position statement of SEQCML/SEEN/SEEP. Advances in Laboratory Medicine 2023 · PMID 37359897
• Li D, Ferguson A, Cervinski MA, Lynch KL, Kyle PB. AACC Guidance Document on Biotin Interference in Laboratory Tests. J Appl Lab Med 2020 · PMID 32445355