SPECIALTY TOPICS · GUIDE
Insulin Resistance and Metabolic Aging
What insulin resistance is, how it relates to aging, what mouse studies of lower insulin show, and what the Diabetes Prevention Program found in people at high risk.
Content last updated . This page has not been medically reviewed.
Back to Longevity & Healthy AgingWhat a large human trial found
The Diabetes Prevention Program randomly assigned 3,234 adults with elevated fasting and post-meal glucose to placebo, metformin, or a lifestyle program aiming for at least 7 percent weight loss and 150 minutes of weekly activity. [4] Over an average of 2.8 years, lifestyle change reduced the number of new diabetes cases by 58 percent and metformin by 31 percent compared with placebo. [4] The NIDDK says the program showed that for people at high risk, losing 5 to 7 percent of starting weight helped reduce the chance of developing diabetes. [1]Label: established for diabetes prevention in people at high risk. That outcome is a disease outcome, not a longevity outcome: the trial did not test lifespan. Metformin was one arm of this trial, which tested diabetes prevention and not aging. Metformin's aging research is covered at metformin and aging research.
Exercise, antioxidants and insulin sensitivity
A small trial in 39 healthy young men found exercise improved insulin sensitivity only in men who did not take antioxidant vitamins C and E, which blocked the effect in that study. [5] This is a short, small result that is discussed with other antioxidant evidence on oxidative stress and antioxidant defenses.Frequently asked questions
What is insulin resistance?
It is a condition in which the body does not respond to insulin the way it should. [1]
Does insulin resistance cause aging?
That has not been established. The 2017 mouse study suggests elevated insulin contributes to age-related insulin resistance in mice, but it is animal evidence. [3]
Can lifestyle change prevent type 2 diabetes?
In the Diabetes Prevention Program, a lifestyle program cut new diabetes cases by 58 percent compared with placebo in high-risk adults. [4]
Is there a standard test for insulin resistance?
The NIDDK says clinicians may not test for it, and the test is mainly used in research. [1]
Does metformin slow aging?
Metformin lowered diabetes incidence in the Diabetes Prevention Program, but that is not a test of aging. [4]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
How to read the evidence labels
Labels used on this page: approved medicine, established, promising but limited, mixed, insufficient evidence and preclinical (cells/animals only).
What insulin resistance is
Insulin helps glucose move from the blood into muscle, fat and liver cells. In insulin resistance those cells respond poorly, and over time the pancreas may not make enough insulin, so blood glucose rises. [1] When glucose is higher than normal but below the diabetes cutoff, the condition is called prediabetes. [1] The US National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) says researchers do not fully understand what causes insulin resistance and prediabetes, and that clinicians may not test for insulin resistance because that test is mainly used in research. [1] The NIDDK reports that in 2021 about 97.6 million US adults had prediabetes. [1] (Page last reviewed March 2025.)Where "metabolic aging" fits
"Metabolic aging" is not a diagnosis. It is a research phrase for age-related changes in how the body handles glucose, fat and energy. In the 2023 update of the hallmarks of aging, "deregulated nutrient-sensing" is listed among twelve proposed hallmarks. [2] Hallmarks are a framework for research and not a treatment map; see the hallmarks of aging and mTOR, AMPK and nutrient-sensing pathways.What an animal study suggests
In a 2017 mouse study, halving the Ins2 gene lowered circulating insulin by 25 to 34 percent in aged female mice. These mice had lower fasting glucose, better insulin sensitivity and extended lifespan on two diets. [3] The authors concluded that elevated insulin may contribute to age-related insulin resistance and that limiting basal insulin can extend lifespan in mice. [3]Label: preclinical (cells/animals only). Genetic changes in mice do not show that lowering insulin would extend life in people. For the reason, see aging in animals vs humans.
Safety and limits
- Do not start, stop or change a diabetes or other medicine because of anything here. Talk with the prescriber.
- Home glucose monitors in people without diabetes are covered at continuous glucose monitors in people without diabetes.
- For practical guidance and when to seek care, see prediabetes, type 2 diabetes and metabolic syndrome.
- GLP-1 medicines are prescription drugs; their aging research is covered at GLP-1 medicines and healthy aging research.
References
- NIDDK, Insulin Resistance & Prediabetes. Last reviewed March 2025. Read 2026-10-22.
- López-Otín C et al. Hallmarks of aging: An expanding universe. Cell, 2023. Read 2026-10-22.
- Templeman NM et al. Reduced circulating insulin enhances insulin sensitivity in old mice and extends lifespan. Cell Reports, 2017. Read 2026-10-22.
- Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. New England Journal of Medicine, 2002. Read 2026-10-22.
- Ristow M et al. Antioxidants prevent health-promoting effects of physical exercise in humans. PNAS, 2009. Read 2026-10-22.