Changes in your nails can sometimes reflect what’s happening inside your body, especially after 40. While some changes are harmless, others may signal underlying health issues that shouldn’t be ignored.

Horizontal lines, also known as Beau’s lines, can indicate past illness, stress, or chronic conditions like diabetes or circulation problems. These lines often appear after the body has gone through a significant physical challenge.

Vertical ridges are common with aging, but if they become deep or uneven, they may suggest deficiencies such as low iron or vitamin B12. Monitoring their appearance can help identify potential nutritional issues early.

More serious signs include dark streaks. As noted, “Sudden appearance of dark streaks may signal melanoma,” which requires immediate medical attention. Similarly, white lines, called Muehrcke’s lines, may be linked to liver or kidney issues or low protein levels.

The key message is simple: “changes in your nails—especially unusual lines—should not be ignored.” They can act as early warning signs, so noticing and checking unusual changes with a healthcare provider can help detect problems before other symptoms appear.