How our body regenerates

If an axolotl loses a limb, it grows a new one in just five weeks. With people, this only happens in Hollywood films. Or perhaps not? Cutting-edge cell research shows that almost all human cells regenerate.

Text: Michael Suter; infographic: Codeplay

It is a long-held myth that the human figure, hair and personality change every seven years. However, cutting-edge cell research today shows that our body really does regenerate – but it does so constantly. Be it our skeleton or organs, some cells are completely replaced within a short period of time, some regenerate only partially and over a period of some years, while others never regenerate. In fact, our most essential organ – the heart – is only able to regenerate up to 40% of its cells over the course of its lifetime. How do other body cells compare?

The effects of stopping smoking are immediately noticeable. Our sense of smell and taste recovers after just two days. And after five years, the risk of a heart attack is similar to that of a non-smoker.

New skin cells are constantly being generated in the basal cell layer. They keratinize within four weeks and move to the surface of the skin. Our skin completely regenerates in just one month. So this happens 12 times a year and 120 times in 10 years.

Good news for organ donors: The liver is the only organ that grows back to its original size if pieces of it are removed.

Our nails not only look different, they also grow at different rates. On average, they grow by about 0.5 to 1.2 mm a week. The nails of the middle fingers grow fastest. Nails grow more slowly if we’re sick and as we get older.

On average, our hair grows by 1 to 1.5 cm a month. How fast our hair grows depends on age, hormones and ethnicity.

Mature blood cells have a limited life span. Our body must therefore constantly produce new blood cells. The bone marrow produces several billion blood cells a day.

Our bones also renew themselves, but in many cases the system doesn’t work as well in older people as it does in young people, which is why the risk of bone diseases, such as osteoporosis, increases.

Take our quiz to find out how much you know about regeneration. You’ll find the answers below. Have fun!