Hair Loss and Thinning Hair: Is Your Thyroid to Blame?

Watching your hair thin or fall out can be incredibly distressing. While hair loss has many causes, your thyroid could be playing a bigger role than you realize. Understanding this connection can help you get the answers — and relief — you need.

Why This Symptom Matters

Your thyroid controls your body’s metabolism, including how your hair grows and regenerates. When thyroid hormone levels are too high or too low, it disrupts the normal hair growth cycle. This can lead to noticeable thinning, hair falling out in clumps, or changes in hair texture.

With hypothyroidism (underactive thyroid), hair often becomes dry, brittle, and falls out more easily. The hair loss is typically gradual and affects the entire scalp, not just specific areas. You might also notice your eyebrows thinning, especially the outer third.

Hyperthyroidism (overactive thyroid) can cause hair to become fine and weak, breaking easily. The hair loss tends to be more sudden and dramatic. Many people also experience changes in hair color or texture during thyroid imbalances.

The good news? Thyroid-related hair loss is often reversible once hormone levels are properly managed. However, it can take several months for hair to regrow after treatment begins, as hair follicles need time to reset their growth cycle.

Could It Be Your Thyroid?

Hair loss has many potential causes beyond thyroid issues. Genetics, hormonal changes (like menopause), certain medications, stress, nutritional deficiencies, and autoimmune conditions can all affect hair growth. Even tight hairstyles or excessive heat styling can cause thinning.

However, thyroid testing makes sense if you’re experiencing hair loss alongside other symptoms. These might include unexplained weight changes, feeling unusually hot or cold, fatigue, mood changes, or changes in your menstrual cycle. Family history of thyroid disease also increases your risk.

Women are particularly susceptible to thyroid-related hair loss, especially during pregnancy, postpartum, or menopause when hormones naturally fluctuate. If your hair loss seems disproportionate to other life factors, a thyroid evaluation is a smart first step.

What Tests Should You Consider?

For hair loss concerns, a comprehensive thyroid panel gives you the clearest picture. TSH (thyroid stimulating hormone) is the standard screening test, but additional markers can reveal issues TSH might miss. Free T4 measures your active thyroid hormone, while Free T3 shows how well your body converts and uses thyroid hormones.

If autoimmune thyroid disease runs in your family, antibody tests like TPO and thyroglobulin antibodies can detect conditions like Hashimoto’s disease, which often causes gradual hair thinning. These tests help identify thyroid problems even when other markers appear normal.

What to Expect from Testing

Thyroid testing is straightforward and convenient. Most services let you order tests online without a prescription, then visit a nearby lab for a simple blood draw. The process takes just minutes, and you’ll typically receive results within 1-3 business days through a secure online portal.

Your results will show whether your thyroid hormone levels fall within normal ranges. If abnormal, you’ll want to share these results with a healthcare provider who can recommend next steps, including potential treatment options.

When to See a Doctor

While at-home thyroid testing is valuable for screening, certain situations warrant immediate medical attention. See a doctor promptly if you experience sudden, dramatic hair loss, hair loss in patches, scalp irritation or pain, or hair loss accompanied by severe fatigue, heart palpitations, or significant weight changes.

Also consult a healthcare provider if your test results show abnormal thyroid levels, or if you have normal thyroid results but continue experiencing concerning symptoms. They can evaluate other potential causes and recommend appropriate treatment.

This content is for informational purposes only and does not constitute medical advice. Always consult a healthcare provider for diagnosis and treatment.