Diet and exercise produced more consistent effects on age-related goals than many supplements, according to an analysis of 51 human studies. Certain medications also changed these goals – especially in people who were being treated for diseases they already had.
The researchers collected studies that use DNA-based age tests. These tests estimate aspects of biological aging based on chemical marks on the genetic material – but they do not directly measure how many years someone will live.
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The analysis, which is published in Nature Medicine, aims to clear up a field where different studies use different biological clocks. The core question was which treatments produce measurable changes across a broader set of tests.
Chronological age counts the years since birth. Biological age measures instead try to capture age-related changes that may vary between people of the same chronological age.
Many such tests look at DNA methylation – chemical markers that help regulate gene activity without altering the genetic material itself. Patterns in these markers can be used to build statistical predictions related to age or health.
The team used an analysis platform called TranslAGE to look at 16 ageing clocks and 94 additional methylation-based measures. A common framework made it easier to compare findings that might otherwise seem contradictory.
Exercise and diet had the clearest impact
Lifestyle treatments that combined exercise and dietary changes produced relatively consistent signals. Mediterranean-inspired, low-carb, and low-fat-based approaches were among the dietary treatments examined – although the studies did not establish one universal best diet.
Medications such as metformin, semaglutide, and treatments that block an inflammatory signal called TNF also affected age-related targets. Some of the strongest responses were seen in people with disease, where the treatment may improve the underlying health problem.
However, many over-the-counter supplements and certain medical procedures showed little measurable effect in the available studies. This applies to the treatments and tests that were investigated – not every single product or every possible health effect.
The choice of clock also plays a role
Newer watches were often more responsive to treatment than older ones – illustrating that a claim of altered biological age depends in part on how biological age is measured.
The studies varied in participants, duration and treatment schedule. The results cannot therefore be treated as a direct competition that proves that one treatment is superior to another for an otherwise identical person.
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Most importantly: Altered score is not evidence of rejuvenation
A change in a DNA-based score is not evidence of rejuvenation, longer life, or fewer future diseases. These measures still need validation as reliable indicators of real health benefits.
Larger and more diverse studies are needed to determine which changes predict lasting health improvements. Researchers also need to find out how long the clock changes persist after a treatment has ended.
The analysis offers a stronger way to test ageing claims – while keeping its limitations visible. It suggests that established health treatments deserve careful study, but that a lower biological age alone is not enough to show an anti-ageing breakthrough.
