Does metformin help you live a longer, healthier life?
For people with type 2 diabetes, metformin has real health benefits, but whether it also keeps healthy people fit for longer is something we do not yet know. Wait for the results of the large ongoing studies before considering it as an anti-aging agent, and always discuss its use with your doctor.
That metformin extends lifespan in people without diabetes has not yet been demonstrated. Early observational research surprisingly found that diabetes patients on metformin sometimes appeared to live longer than healthy people without diabetes. But those studies had serious methodological problems, and attempts to replicate them have produced mixed results.
In the background, something genuinely interesting is going on. In cell and animal research, metformin inhibits several processes associated with aging: chronic inflammation, stem cell aging, oxidative damage, and the shortening of telomeres (the protective ends of chromosomes). It also activates an internal cellular cleanup mechanism that works through a protein called AMPK. But this kind of laboratory result does not automatically mean that the drug turns back the clock in healthy people as well.
In people with type 2 diabetes, there is reasonable evidence that metformin reduces the risk of cardiovascular disease and certain forms of cancer, thereby extending the period of life spent in good health. Whether that benefit also applies to people without diabetes is the central unanswered question. The large clinical trial designed to find out (the TAME trial) is still ongoing. A smaller precursor study showed changes at the gene level associated with aging, but that is not yet proof that people remain healthy for longer as a result.
If you use metformin over the long term, there is one concrete risk to keep in mind: the drug reduces the absorption of vitamin B12, and a deficiency can develop with prolonged use. This can cause neurological complaints. Regular monitoring of your B12 levels is therefore advisable. Another point of attention is exercise: there are indications that metformin partly negates the fitness gains from endurance sports, although this has not yet been studied sufficiently to draw firm conclusions.
All sources are reviews; no randomised trials or meta-analyses are included in the list. The TAME trial and MILES study are discussed but have not yet been completed. Roundworm research is the only direct causal evidence for lifespan extension, but that is far removed from humans.
How does metformin work in your body?
Metformin lowers blood sugar primarily by suppressing glucose production in the liver, through multiple interrelated mechanisms. Exactly how those mechanisms work together has not yet been fully resolved, but the effect itself is not in dispute.
What do we really know about metformin and ageing?
Metformin may extend your healthy years by helping to prevent disease, from diabetes to heart and vascular disease. Whether it also slows ageing itself in people without diabetes is for the TAME trial to show, the first large study to test that directly. If you are considering it for that reason, expect stomach and bowel complaints and a falling folate level.
What are the side effects of metformin?
Metformin causes gastrointestinal complaints such as diarrhoea, nausea and vomiting in a substantial proportion of users. Discuss with your doctor whether the dose can be built up gradually, or consider an alternative if the complaints persist.
Does rapamycin help people live longer in good health?
Rapamycin demonstrably extends the lifespan of mice and other animals, but whether the same holds true for humans has not yet been supported by large clinical studies. Do not use it without medical supervision: side effects are real and many organ systems have barely been studied in humans.
Does metformin help with weight loss?
Metformin helps with weight loss, but the effect is modest: expect a few kilograms, not a dramatic transformation. Lifestyle changes work better in the short term, but weight loss with metformin remains stable over the long term. Discuss it with your doctor if you want to know whether it suits your situation.
Does metformin lower your risk of cancer or dementia?
In people with diabetes there are indications that metformin lowers overall cancer risk, but the evidence varies or is absent depending on the specific cancer type. Based on the available studies, no conclusions whatsoever can be drawn regarding dementia.