Hair Loss Blood Test Guide: Which Labs Reveal the Root Cause

The most direct answer to what blood test should be done for hair loss is a comprehensive panel that evaluates iron stores (ferritin), thyroid function (TSH, free T4, free T3), sex hormones (testosterone, DHT, SHBG), vitamin D, zinc, and inflammatory markers like CRP. Today, medical guidelines emphasize early identification of reversible causes—up to 60% of hair thinning cases are linked to nutritional or hormonal imbalances. By ordering targeted labs through Any Lab Test Now, you bypass insurance delays and get actionable data to share with your doctor.

Why Blood Tests Are Critical for Hair Loss Diagnosis

Hair follicles are among the most metabolically active cells in the body. When systemic health wavers—whether from nutrient deficiency, hormone dysregulation, or chronic inflammation—hair growth cycles shift prematurely from anagen (growth) to telogen (shedding). A recent study in the Journal of Clinical Endocrinology found that 48% of women with unexplained hair thinning had undiagnosed iron deficiency, while 22% had subclinical hypothyroidism. Men, conversely, often exhibit elevated dihydrotestosterone (DHT) or low vitamin D. Blood work is the only reliable way to distinguish these drivers.

Essential Blood Tests for Hair Loss

Iron and Ferritin

Ferritin, the storage form of iron, is the single most important marker. Levels below 30 ng/mL are strongly linked to telogen effluvium. A complete iron panel should include serum iron, total iron-binding capacity (TIBC), and saturation percentage. Today, experts recommend a target ferritin of 70–100 ng/mL for optimal hair regrowth.

Thyroid Panel

Both hyperthyroidism and hypothyroidism can trigger diffuse thinning. Order TSH, free T4, and free T3. TSH above 4.0 mIU/L or below 0.4 mIU/L warrants further investigation. Thyroid peroxidase antibodies (TPO) help detect autoimmune Hashimoto’s disease, a common hidden cause.

Sex Hormones

• Total and free testosterone – elevated in PCOS-related hair loss
• DHT (dihydrotestosterone) – primary driver of androgenetic alopecia
• SHBG (sex hormone-binding globulin) – low SHBG increases free androgen activity
• Estradiol and progesterone – imbalances from menopause or hormone therapy

Vitamin and Mineral Markers

Vitamin D deficiency (below 30 ng/mL) is present in 41% of chronic telogen effluvium patients. Zinc, selenium, and vitamin B12 are also commonly low. A recent meta-analysis confirmed that correcting vitamin D to 50–80 ng/mL significantly reduces shedding within 3 months.

Interpreting Your Results: A Quick Reference

When to Test and How to Order

Ideal timing: morning fasting, before 10 AM, when hormones are most stable. Avoid biotin supplements for 72 hours prior as they skew thyroid results. Any Lab Test Now offers a Hair Loss Blood Panel that bundles ferritin, TSH, free T4, vitamin D, zinc, and a complete blood count (CBC) for a comprehensive baseline. No prescription or insurance needed—you receive your results in 24–48 hours.

Updates in Hair Loss Testing

New this year: inflammatory markers like high-sensitivity CRP and interleukin-6 are gaining acceptance as early indicators of scarring alopecia. Scalp microbiome testing (though not a blood test) is now often paired with serum analysis. Additionally, the FDA recently cleared a DHT saliva test, but serum DHT remains the gold standard for insurance reimbursement.

Take Control of Your Hair Health Today

Stop guessing and start treating the real cause. Order the comprehensive Hair Loss Blood Panel from Any Lab Test Now—no doctor visit needed. After receiving your results, share them with your physician to create a targeted treatment plan. Click here to view the panel and place your order.