Healthy nails generally grow about 1 millimeter per week (twice as fast as nails) and take about six months for the nail to grow completely from the base up. Heavy stress can accelerate the growth of nails to beat its strength. In addition, stress can also trigger the unconscious habit to scratch / scrub or bite the fingernails to cause the nail pillow to erode. As a result, the nails will be wavy and brittle when growing back.
