As the title suggests, I\’ve noticed that my fingernail grow much faster than my toenails. For instance, I usually trim my fingernails every two week or so, but for toenails the number would be about 6 to 8 weeks. A bit of research revealed this In mammals, the length and growth rate of nails is related to the length of the terminal phalanges (outermost finger bones). Thus, in humans, the nail of the index finger grows faster than that of the little finger; and fingernails grow up to four times faster than toenails.  In humans, nails grow at an average rate of 3 mm (0. 12 in) a month.  Fingernails require three to six months to regrow completely, and toenails require 12 to 18 months. Actual growth rate is dependent upon age, sex, season, exercise level, diet, and hereditary factors. Nails grow faster in the summer than in any other season.  But, so why should the growth rate of nails depend on the length of the terminal phalanges? Then why do babies grow nail much faster? I wasn\’t satisfied by its answer, so I looked a bit more where I found. They had two possible candidates: because hands are physically closer to the heart than are feet, fingers get better blood circulation and consequently better access to oxygen and nutrients.
Fingernails experience almost constant trauma through tapping, typing, bumping, and other seemingly insignificant actions. These persistent minor traumas stimulate fingernail growth. Toes, on the other hand, are not exposed to nearly as much trauma as they are usually bundled up safely inside socks and shoes. Similarly, fingernails on a person\’s right hand grow faster in right-handed people than on their left hand and vice-versa. However they don\’t give actual experimental results. So my question is which of the above is the real cause of this difference in the growth rate of nails; or simply why toenails grow much slower than fingernails? P. S. The season dependence and the lefthand-righthand asymmetry were news to me; it would be really nice if the answer explains them as well. Nails are made of many layers dead keratin protein cells, which are similar to hair and skin cells. The hard part of the nail, called the nail plate, protects the sensitive skin underneath, called the nail bed.
The material that makes up the nail plate is formed in the matrix, located under the cuticle. According to the American Academy of Dermatology, fingernails grow an average 2 or 3 millimeters per month, while toenails grow about 1 millimeter per month. Many factors influence how fast individual nails may grow. The speed of nail growth changes throughout a person\’s lifetime. Infant nails grow more slowly than adult nails, but children\’s nails grow more quickly than those of adults. Nails tend to grow the fastest between the ages of 10 and 14. After that, growth begins to slow, and continues to slow with age. Toenails grow more slowly than fingernails, and the growth rate of each fingernail also differs. The nail on the pinky finger grows the slowest. The thumbnail also grows relatively slowly. On most people, the nails on the index and middle fingers grow the fastest. In general, the difference in growth is quite small, and is measured in tenths of a millimeter. Handedness can also affect nail growth, so the nails on your dominant hand grow faster than those on the non-dominant hand. Additionally, people who use their hands a lot on a daily basis tend to have faster nail growth than people who don\’t use their hands much.
The weather can affect nail growth. Nails grow faster in warm weather than they do in cold weather. The American Academy of Dermatology points out that a hormone imbalance can cause nails to grow more slowly. However, hormones can affect nail growth in healthy people as well. For example, women tend to experience faster nail growth during pregnancy and slower nail growth during lactation. Women also might experience faster nail growth right before menstruation begins. Cutting your nails causes them to grow a little more quickly. Nail-biting also makes nails grow more quickly. Compulsive nail-biting, however, can lead to infection or permanently damage the nail and nail bed, which may cause a nail to stop growing. The condition and growth rate of the nails can be indicative of a health condition. The American Academy of Dermatology states yellow nails may indicate diabetes, while yellowing thick nails that grow slowly might be a symptom of a lung condition. Nail growth may also be slowed by poor circulation.