Can Scientists Slow Biological Aging? What the Research Shows

Aging is the biggest risk factor for nearly every major disease, and over the past two decades it has come to be seen by many researchers as a process that might be slowed rather than a fact to be accepted. Here is where the evidence stands, as of late 2026.

Has aging been slowed in any animal?

Yes, repeatedly, in laboratory animals. The clearest case is rapamycin, a drug that blocks a nutrient-sensing pathway called mTOR. In the National Institute on Aging’s Interventions Testing Program, which tests drugs in mice at several centers at once, rapamycin consistently extended both median and maximum lifespan, according to a 2023 review in Cell Metabolism. Drugs that kill senescent cells, worn-out cells that stop dividing but linger and inflame surrounding tissue, have improved physical function and delayed frailty in mice. Metformin, a diabetes drug, delays aging in worms and mice. And intermittent, controlled expression of the Yamanaka factors, four proteins that can reset a cell toward a stem-cell state, has forestalled aging and extended lifespan in genetically altered mice, though constant expression causes cancer.

A fruit fly given a combination of three drugs lived 48 percent longer, according to a 2026 review. Flies are not people.

What has been tried in people?

The main candidates and their status:

• Rapamycin. The strongest animal data of any drug, but human use for healthy aging is off-label. Trials in people have been small; one placebo-controlled trial of rapamycin applied to the skin increased skin thickness and reduced senescent cells. The Cell Metabolism review calls it a two-edged sword with side effects that must be weighed against uncertain benefits.
• Metformin. Strong evidence in diabetes, and some suggestion it slows aging processes in the short term. The TAME trial (Targeting Aging with Metformin), designed with the FDA to test whether it delays age-related diseases in non-diabetic older adults, would be the first trial where the indication is aging itself. As of 2026 it is only partly funded and has not fully launched, according to two summaries of the field. Taking metformin to slow aging without a metabolic disease is not currently recommended.
• Senolytics. Combinations such as dasatinib plus quercetin, or fisetin, are in early human trials for conditions including lung fibrosis, Alzheimer’s disease, and kidney disease. They remain experimental.
• Partial reprogramming. The field’s most-watched frontier. The first human trial, for an eye condition, received FDA clearance in 2026, according to a longevity site. There is no approved reprogramming therapy and real safety questions remain.
• Other repurposed drugs. Nir Barzilai, who leads the TAME effort, told the AAMC that metformin, SGLT2 inhibitors, and GLP-1 drugs prevent cardiovascular disease, diabetes, and kidney disease and may prevent Alzheimer’s disease, and that his group has identified already-approved drugs as low-hanging fruit for aging research.

Has anything been proven to extend human life?

No. Every serious review reaches the same conclusion: as of 2026, no drug, supplement, or therapy has been shown in a rigorous human trial to extend human lifespan or reverse biological age. Some interventions have moved readings on “epigenetic clocks,” blood tests that estimate biological age from chemical tags on DNA, but one trial that improved one clock showed no change on two others, and the clocks themselves are research tools, not validated measures of how long you will live.

Why is it so hard to test?

Because a lifespan trial in humans would take decades, and aging is not a recognized disease that drugs can be approved to treat. That is why TAME was designed around delaying diseases of aging rather than extending life, and why most trials use surrogate markers. It is also why the animal evidence runs so far ahead of the human evidence: a mouse study takes three years.

What does the evidence actually support doing?

The unglamorous things. Regular exercise, adequate sleep, a diet rich in plants, not smoking, and treating blood pressure and blood sugar have strong human evidence for extending healthy years, and none of the experimental drugs has shown anything comparable in people. One 2026 summary reports that six months of structured exercise lowered one epigenetic clock by several months, for whatever that measure is worth. The experimental therapies may someday add to this list; today they are experiments.

How should I think about longevity claims?

Ask three questions. Was it tested in humans? Was the outcome a disease or death, not a marker? And who is selling it? A great deal of what is marketed as anti-aging rests on mouse data, markers, or nothing. For the biology behind all this, see why we age and die; for what very long-lived animals suggest, see why scientists study long-lived animals; and for the ceiling question, see could humans ever live to 150.

This is general educational information, not medical advice. Research in this area moves quickly and this page reflects sources available at the date shown; check the date and the sources before relying on a specific claim.