Scientists have for decades searched for ways to extend human lifespan. Research has shown that certain lab animals can live longer when they eat less, but similar studies haven’t been done on humans.
A study from nearly a hundred years ago found that rats who consumed less food lived longer than those who ate regularly, though sticking to a permanent diet is extremely difficult for most people.
Now, researchers from the School of Biological Sciences at the University of East Anglia suggest that a mix of FDA-approved drugs could offer a solution. The two drugs—Rapamycin and Metformin—mimic the effects of calorie restriction and have been shown to increase the lifespan of mice by up to 30%.
Rapamycin, originally discovered in the 1970s from bacteria in the soil of Easter Island, has long been used as a potent immunosuppressant to prevent organ transplant rejection.
It functions by turning off a specific cellular signal that tells cells they have an abundance of nutrients. Metformin, on the other hand, is a synthetic compound derived from the French Lilac (also known as Goat’s Rue) and is commonly prescribed to manage blood sugar levels in people with type 2 diabetes, Indian Express reported.
Because both drugs play roles in detecting nutrient and energy levels in the body, biologists were interested in whether using them together could replicate the benefits of a calorie-restricted diet.
To explore this, researchers reviewed thousands of prior studies and identified 167 focused on eight different vertebrate species—including fish and monkeys—which provided detailed insights into the effects of these drugs on animals.
Among the three main strategies linked to longer life—calorie restriction, Rapamycin, and Metformin—scientists found that reducing food intake is the most reliable method for extending lifespan, regardless of the animal's sex.
Rapamycin ranked as the second most effective option, while Metformin showed little to no significant impact. However, researchers pointed out that Rapamycin's effects varied across studies; in some instances, both dietary restriction and Rapamycin actually shortened lifespan.
It is also important to note that most of the favourable outcomes were observed in mice and rats, which, while genetically similar to humans, are not identical.
Given that Rapamycin can cause side effects such as weakened immunity, scientists are now investigating whether smaller doses could deliver benefits without the associated risks.
An ongoing human trial involving Rapamycin has shown some promise, suggesting that lower doses might help extend lifespan. However, the study is still underway, and final results are expected to take a few more years.