"Ageless" is a favorite word in beauty ads. But the real question behind it is much bigger: can humans become ageless, meaning not just looking young but actually stopping the body from getting older? Today the answer is no. Every person ages. But biology has some surprising examples of creatures that barely age, and scientists are studying whether any of their tricks could ever help us.
What "ageless" means to a biologist
For most animals, including us, the risk of dying rises every year after adulthood. Our bodies slowly get weaker, more fragile and more prone to disease. That's aging.
An ageless animal would be one whose risk of dying doesn't climb with time, and whose body doesn't gradually wear out. Biologists call this negligible senescence. These animals still die, from predators, accidents or disease, but not from growing old in the way we do.
Animals that seem to be ageless (or close)
Hydra
Hydra are tiny freshwater animals related to jellyfish. In long-term lab studies, they show little or no sign of increasing death risk with age. They constantly renew their bodies from stem cells.
The "immortal jellyfish"
Turritopsis dohrnii can turn itself back into an earlier life stage, a polyp, when it's damaged or stressed, and then grow up again. It's the closest thing nature has to hitting a reset button.
Naked mole-rats
These odd-looking rodents live for decades, far longer than other rodents their size, and are remarkably resistant to cancer. Their aging appears very slow.
Turtles, tortoises and some fish
Some turtles and tortoises appear to age very slowly, and some fish live for centuries. The Greenland shark is believed to live for several hundred years.
None of these animals is literally immortal, and their bodies are very different from human bodies. But they prove that fast aging isn't a law of nature for every living thing.
Why humans age
Scientists group the causes of aging into several overlapping kinds of damage, including:
- DNA damage that builds up over a lifetime.
- Shortening telomeres, the protective caps at the ends of chromosomes, which limit how many times many cells can divide.
- Senescent cells, old cells that stop working but don't die, and release substances that inflame nearby tissue.
- Worn-out cell machinery, including mitochondria, the parts of cells that make energy.
- Changes to how genes are switched on and off as we age.
To become ageless, a person would need all of these fixed or prevented, not just one. That's why no single pill or treatment can do it.
Research that aims to turn back the clock
Cell reprogramming
In 2006, Japanese scientist Shinya Yamanaka discovered that a few genes could turn adult cells back into a young, stem-cell-like state, work that later earned a Nobel Prize. Researchers have since tried "partial" reprogramming, turning cells only part of the way back, and have reversed some signs of aging in mice. It's exciting, but it carries risks, including cancer, and it's still lab research.
Clearing old cells
Drugs called senolytics remove senescent cells. In mice they've improved several signs of aging. Human trials are early.
Drugs that slow aging in animals
Rapamycin has extended lifespan in mice in careful studies. Whether it does anything similar in people is unknown.
So, can humans become ageless?
Honestly:
- Today: no treatment stops or reverses human aging.
- Soon: we may get treatments that slow some parts of aging or delay age-related diseases. That would be a huge achievement, even if it falls short of agelessness.
- Someday: nobody knows. Some scientists believe aging will eventually be treatable like a disease; many others think that's very far off or unrealistic.
Be wary of anyone selling agelessness today. No product, cream or clinic can deliver it. Our guide to anti-aging vs. cryonics has tips on spotting overhyped claims.
What you can do in the meantime
You can't become ageless, but you can age better: stay active, don't smoke, eat well, sleep, and stay connected with people. Our guide to longevity science covers what has the best evidence.
And it's worth thinking about the bigger question. If science someday could restore people who had died, would you want that chance? Under what conditions? Writing your answer down, even "not sure yet," helps your family know your wishes. The Revival Registry is a private place to do that.