Harvard doctor reveals signs on fingernails predict longevity

'The rate at which your nails grow is a really good indicator of how well you're aging,' Dr. Sinclair said in an episode of the Lifespan podcast. He cited a 1979 study in which scientists tracked the growth of hundreds of people's nails over several years. The results showed that nail growth slowed by about 0.5% per year after age 30. When less blood is delivered to the fingertips, the nails grow slower and weaker, experts say. In addition to age, other factors that affect nail growth include: diet (deficiencies in vitamin A, zinc, calcium, or iron can cause nails to grow more slowly and become brittle); hormonal changes (puberty and pregnancy often cause nails to grow faster due to hormonal influences); underlying medical conditions (certain chronic heart and lung conditions can reduce the amount of oxygen reaching tissues, affecting nail growth).

People whose nails grow faster and need to be trimmed more often than their peers may be aging more slowly than average. This means they can maintain their youthful appearance longer and have a higher chance of living longer than those whose nails grow slowly. Because when the body produces new cells quickly, the replacement and regeneration process is strong, helping to maintain youthfulness and slow down the effects of biological aging (the actual age of cells and tissues in the body, not necessarily the same as the age according to birth year).

Dr David Sinclair, a geneticist at Harvard Medical School, said the growth rate of fingernails indicates the rate of aging and predicts longevity. Photo: Dailymail

Dr. Sinclair revealed that he also regularly pays attention to the growth rate of his nails: "Every time I have to cut my nails, I wonder, how long has it been?"

In addition to growth rate, nail shape can also reflect health status.

- Ridges on the nails: Often seen in older people due to the slowing down of new cell production. However, if it appears in young people, it can be a sign of mumps, diabetes, hyperparathyroidism or vitamin deficiency.

- Dark spots under the nail: Can be a sign of melanoma (a form of skin cancer) or warts under the nail bed.

- White spots on nails: Shows that the body is not absorbing enough zinc, calcium or iron, or can be a sign of a fungal infection.

- Clubbing (nails that widen and curve around the fingertips): May be associated with heart or lung disease or low blood oxygen levels.

Recognizing signs of illness through fingernails. Photo: Dailymail

Despite the controversy, monitoring your nails for unusual signs is still a simple way to help you grasp your overall health. If you notice a significant change in the growth rate, color, or shape of your nails, you should consult a doctor for a timely health check.

Kareem Winters

Update 19 February 2025