Could ridges in my nails be a sign of a thyroid problem?

Yes, nail ridges can be a sign of thyroid problems. Both hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid) can cause visible nail changes, including vertical or horizontal ridges, brittleness, dryness, splitting, and slow nail growth. These changes occur because thyroid hormones play a key role in cell regeneration and keratin production, which directly affect nail health.

However, nail ridges alone aren't a definitive diagnosis. They can also result from aging, nutrient deficiencies (like iron, biotin, or zinc), eczema, or injury. If you notice ridges alongside symptoms like fatigue, weight changes, hair loss, temperature sensitivity, or mood shifts, a thyroid issue becomes more likely.

Because nail ridges can point to many possible causes, it's worth understanding your full symptom picture before assuming the worst—or dismissing it. A free, instant, online symptom check can help you connect the dots between your nail changes and other clues your body may be giving you, guiding you toward the right next steps and whether to see a doctor.

Reviewed for medical accuracy: 07/15/2026