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Published on: 8/20/2026

What do different types of lines in fingernails indicate about my health?

Yoshinori Abe

Reviewed by Yoshinori Abe, MD

Internal Medicine

Lines in fingernails can reveal important clues about your health. They may indicate past illness, injury, nutritional deficiencies, or an underlying health condition.

What do lines in fingernails mean?

  • Horizontal lines (Beau's lines): Often signal a past illness, high fever, injury, or stress that temporarily halted nail growth.
  • Vertical ridges: Usually a normal part of aging, but can occasionally point to nutrient deficiencies.
  • Dark vertical lines: Should be evaluated promptly, as they may indicate a more serious condition.
  • White lines (Mees' lines): Can be linked to systemic illness or exposure to certain toxins.

Because nail changes can reflect anything from minor stress to significant health issues, it's worth understanding what your body may be telling you. Instead of guessing—or worrying unnecessarily—take a few minutes to complete a free, instant, AI-powered symptom check. It's private, evidence-based, and helps you identify possible causes and next steps so you can make informed decisions about your health with confidence.

Reviewed for medical accuracy: 07/15/2026

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Explanation

Fingernail lines can be more than just a cosmetic issue; they might reveal important information about your health. Beau's lines, which are horizontal indentations across the nail, often appear after an illness or injury that temporarily stops nail growth. These lines can also be linked to conditions like diabetes or malnutrition.

Mees' lines are white lines that run across the nail and can be a sign of arsenic poisoning or other systemic issues. Muehrcke's lines are pairs of white lines that appear across the nail and may indicate liver or kidney problems.

Vertical lines, or longitudinal ridges, are usually harmless and can be a normal sign of aging, but if they are dark or change in appearance, they should be checked by a healthcare provider.

If you notice new or changing lines in your nails, you can use Ubie's free AI-powered symptom checker to help understand what might be causing them and whether you should seek medical attention.

(References)

  • Lipner SR, & Scher RK. (2016). Evaluation of nail lines: Color and shape hold clues. Cleveland Clinic journal of medicine, 27168515.

  • Braswell MA, Daniel CR 3rd, & Brodell RT. (2015). Beau lines, onychomadesis, and retronychia: A unifying .... Journal of the American Academy of Dermatology, 26475537.

  • Fawcett RS, Linford S, & Stulberg DL. (2004). Nail abnormalities: clues to systemic disease. American family physician, 15053406.

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