My fingernails keep splitting straight down instead of chipping. What causes this?

Nails are composed of keratin, a protein also found in hair and skin. They grow from the matrix, located under the cuticle at the base of the nail. As new cells form, the older ones are pushed out, forming the hard plate that we recognize as the nail.

Splits typically begin when there is a disruption in this growth process. Factors such as damage to the cuticle or nail bed can affect the health of the nail matrix, leading to weak spots. Over time, these weak spots can develop into full splits, especially if the nails are subjected to additional stress or trauma.

Everyday activities can contribute significantly to nail splitting. Typing on keyboards, playing musical instruments, or using nails as tools to open packages can all exert stress on the nails. Additionally, habitual nail picking or biting can introduce micro-tears that eventually lead to larger splits.