Most ageing researchers don’t want to extend the lifespan. They want to extend the length of time people remain healthy, or what is known as “health span,” said Steven Austad, a professor of biology at the University of Alabama at Birmingham.
“If extra years turn out to be a side effect of keeping people healthy longer, well, that’s great,” he said. “But that’s not the goal.”
People are getting healthier and living longer
A 2025 study reported that the average life expectancy in the United States rose by only about six months from 2009 to 2019, while healthy life expectancy actually declined. In fact, from 2010 to 2019, the United States was the only high-income country in which healthy life expectancy decreased. Put another way, we’ve gotten slightly better at keeping people alive, Austad said, but we’ve also been “increasing the period of ill health at the end of life”.
Austad compared this trend to a game of Whac-a-Mole: as researchers have found effective treatments for diseases like cancer and heart disease, other serious conditions, like dementia, have become more prevalent. Studies even suggest that young adults today are more likely to have chronic health conditions than they were a decade ago. Some experts have argued that the American medical system’s emphasis on treating disease, rather than preventing it, is part of the problem.
Drugs and supplements can extend life span
Peptides, resveratrol, NAD+, growth hormone – influencers claim that products like these can extend the human lifespan, but no drug or supplement has been shown to do that, said Aladdin Shadyab, an associate professor of public health, human longevity science and medicine at the University of California, San Diego.
Some substances have been shown to increase lifespan in worms and mice, but human bodies are very different, he said.
One common claim says that low levels of the enzyme NAD+ are a marker of ageing and that older people can benefit from taking supplements that boost it. But a 2026 study found that NAD+ levels in the blood remain stable in old age, suggesting that replenishment may not be necessary and is unlikely to offer any benefit.
Some of these hacks may actually do harm: a review of clinical trials found that human growth hormone (HGH), which is popular in some longevity circles, can actually increase the risk of health issues like joint pain, swelling and carpal tunnel syndrome in healthy older adults.
Women stay healthy longer than men do
On average, women live about five years longer than men. But they often spend a greater proportion of their late life suffering from illness and disability, said Pankaj Kapahi, a professor who studies ageing at the Buck Institute, in Novato, California.
“Especially after menopause, there is a significant decline in multiple facets of their health,” Kapahi said.
The discrepancy may be a byproduct of the fact that ageing research has traditionally focused more on men than on women and, according to recent research, still does.
Among other things, older women are at a higher risk for autoimmune diseases, arthritis and Alzheimer’s disease, and on average, conditions that are more prevalent among women have been studied less than those that are more prevalent among men.
In addition, most compounds that have been shown to increase lifespan in animal studies seem to work better in males than females, said Viviana Perez Montes, director of the ageing biology division at the National Institute on Aging. No one knows exactly why.
Weight loss is always good for you if you’re overweight
Some studies have linked weight loss with a lower risk of death, but others have not, especially among adults over 65. In a 2023 study, Shadyab and his colleagues found that both intentional and unintentional weight loss among women 61 to 81 was linked with lower odds of surviving to 90, regardless of their starting weight or BMI.
A 2021 meta-analysis of 30 studies also found that weight loss among people aged 65 and older is associated with a 59% higher risk of death. The literature is “pretty mixed,” Shadyab said, adding that weight loss may not always be protective.
Why is this? Some studies suggest that when older people shed pounds, they disproportionately lose beneficial muscle and bone mass rather than fat. The findings illustrate a broader point in longevity research: what benefits younger adults does not always benefit older adults.
If you take good care of yourself, you can live to 100
Recent data suggest that genetics shape half of a person’s lifespan, on average, while lifestyle and environmental factors account for the other half. But among people who live to 95 or older, genetics seem to play an even larger role in their exceptional longevity, Milman said. Studies have shown that people who live to at least 95 do not lead healthier lives – as measured by their weight, diet, physical activity, alcohol use or smoking habits – than people who don’t live that long.
“There’s really nothing different about their lifestyle,” Milman said.
This article originally appeared in the New York Times.
Written by: Melinda Wenner Moyer
©2026 THE NEW YORK TIMES
