THAT'S THE WHY:It's not a question that keeps most people awake at night, but perhaps it may have struck you during the more distracted moments of grooming: why do our fingernails grow more quickly than our toenails?
Nail growth is thought to be generally influenced by nutrition, hormones and disease, yet the literature seems a little fuzzy on exactly why some nails grow more rapidly than others.
A study published in 2009 in the Journal of the European Academy of Dermatology and Venereologywent to the trouble of asking 22 young adults in the US to mark their nails close to the proximal nail fold.
Then between one and three months later, the participants measured the distances between the marks and the proximal nail folds to figure out how much each nail had grown.
The resulting data from 195 fingernails and 188 toenails showed that average fingernail growth rate (3.47mm/ month) was more than twice as fast as that of toenails (1.62mm/month).
Meanwhile, in competitions between fingernails, the little fingernail was the dawdler, while on the feet, the large toenail showed the speediest growth.
Men and younger participants showed faster nail growth overall than women and older participants, but those differences weren’t significant, in the scientific sense. The small study also found no substantial difference between the growth rates of nails on the dominant and non-dominant hands.
The authors argue for the need for further studies to nail down growth rates because clippings are sometimes used to measure “biomarkers” that give clues about a person’s health. “Our findings indicate that toenail clippings as biomarkers may reflect a long exposure time frame given the relatively slow growth rate,” they write.
