Horizontal lines on the nails, known as Beau’s lines, can be a sign that the body has gone through stress or illness. As noted in the original text, “These can suggest past illness, significant stress, or chronic conditions such as diabetes or circulation issues.” While they may fade over time, their presence can reflect deeper health concerns.

Vertical ridges are often harmless and linked to aging, but they are not always insignificant. The article explains that “unusually deep or uneven ridges could point to nutritional deficiencies like iron or vitamin B12 shortage.” When these ridges become more pronounced, they may signal that the body is lacking key nutrients.

Dark streaks under the nails are more concerning, especially if they appear suddenly. According to the article, “Sudden appearance of dark streaks may signal melanoma, a serious skin cancer, and require immediate medical attention.” These changes should never be ignored or assumed to be harmless.

White lines, called Muehrcke’s lines, can also reflect internal health problems. The text states that “These may be linked to liver or kidney problems, or low protein levels.” They often indicate issues that need medical evaluation.

The main message is clear. “After age 40, changes in your nails—especially unusual lines—should not be ignored.” As the article concludes, “Your nails might be revealing health issues before other symptoms appear,” making early medical advice especially important.