Fingernails grow at a standard rate of 0.5-1.2mm per week, averaging about 0.1mm daily. Toenails grow three times slower, at 1.62mm per month. These rates vary between individuals and even between fingers on the same hand. Nails on the dominant hand tend to grow quicker, as do those on longer fingers.
Interestingly, nails that are habitually bitten can grow up to three times faster than healthy nails. This occurs because the trauma from biting stimulates increased circulation in the nail bed. Doug Schoon's research, cited in his book 'Nail Structure and Product Chemistry', illustrates that longer nails grow quickest to provide their protective function.
Complete fingernail regrowth takes three to six months, while toenails need 12 to 18 months. Factors influencing growth speed include age, sex, season, exercise, diet, and genetics. Despite common myths, nails do not grow after death; skin shrinkage creates an illusion of growth.
For salon professionals, understanding these biological variations is key. While external factors like diet or genetics are beyond direct influence, practicing good hygiene is crucial. The variance in growth speed means clients may notice uneven nail lengths, even if they receive consistent care. The stimulation of growth from nail biting offers a unique insight into how trauma can paradoxically promote faster development, although this is not a recommended practice for nail health.
If a client expresses concern about unusually slow nail growth or exhibits related symptoms, professional advice should point them towards a GP. This is because such issues can signal underlying conditions or nutritional deficiencies requiring medical attention.
