The human body probably does not age at a constant rate: several major studies in recent years have identified periods of particularly intensive restructuring of proteins, metabolites, the immune system and other molecular indicators in middle and old age. However, the widely held conclusion that there are two specific "aging spikes" around the ages of 44 and 60 is now in need of revision.
A study by Stanford University scientists, published in the journal Nature Aging on August 14, 2024, analyzed 108 people between the ages of 25 and 75. The researchers collected blood, microbiome samples, and other biomaterials every few months and studied ten types of molecular data at once—from transcriptomics and proteomics to metabolomics, lipidomics, and cytokines. Initial analysis revealed the two most pronounced periods of change around age 44 and 60.
At around age 44, processes related to lipid and alcohol metabolism, the cardiovascular system, skin and muscles were particularly markedly altered. For nearly 60 years, the authors observed changes in immune regulation, carbohydrate metabolism, kidney function, and a number of metabolic processes.
However, on July 15, 2026, Nature Aging added a special editorial disclaimer to the publication. After further review by the authors and independent researchers, the reliability of some of the analysis used to detect peaks in molecular change at specific age periods was questioned. The authors, together with the editors, continue to assess the scale of the problem and possible fixes.
This means that the statement "a person ages sharply precisely at the age of 44 and 60" cannot currently be considered a reliably established scientific fact.
At the same time, the more general conclusion that biological aging can occur unevenly is confirmed by a number of independent studies.
As recently as 2019, scientists who investigated 2,925 blood plasma proteins in 4,263 individuals aged 18 to 95 years, revealed non-linear proteome changes and three periods of increased rearrangement — at approximately 34, 60, and 78 years. The work was published in Nature Medicine.
The difference of the first peak from the later Stanford work was explained by the authors of the latter, in particular, by different methods of measuring proteins and the different age range of the participants. At the same time, both works indicated pronounced changes around the age of about 60.
Another important result appeared in 2025.
The study, published in the journal Cell, created a large-scale proteomic atlas of aging in various human tissues. The scientists found that changes in the protein composition of most of the examined organs noticeably accelerated around the age of 50, especially in the 45-55 age range. Blood vessels turned out to be one of the most sensitive to age.
Thus, this work also supports the idea that there is a period of accelerated biological remodeling in middle age, although it does not specifically confirm the age of 44.
The authors developed separate "proteomic clocks" for different tissues, since the same person's organs can age at different rates. This corresponds to the modern idea of biological age as a heterogeneous process, during which the state of the heart, blood vessels, liver, kidneys or other systems does not necessarily coincide with the calendar age of a person.
Additional data appeared already in 2026. In March, researchers published an analysis of plasma proteins from 50,506 UK Biobank participants in the journal Cell Metabolism. They examined 2,911 proteins and found 1,339 proteins associated with signs of senile fragility — frailty.
During the analysis of changes with age, the scientists obtained a two-phase picture: the most pronounced periods of proteomic rearrangement associated with the frailty of the body were observed around the ages of 50 and 63.
This is especially interesting compared to previous studies: the numbers are accurate vary, but several independent data sets again point to the average age of around 45-55 and the period after 60 as stages of significant molecular remodeling of the body.
A separate large study in Nature Medicine analyzed data from 45,441 UK Biobank participants and 2,897 plasma proteins, after which the scientists constructed a proteomic "aging clock".
It was found that the difference between proteomic and calendar age is associated with subsequent risk of disease and death. A higher estimated biological age was associated, in particular, with the risk of dementia, Alzheimer's disease, chronic kidney disease, coronary heart disease and type 2 diabetes, even after taking into account a number of other risk factors.
The study supports a broader concept: what matters is not so much the specific birthday after which a person supposedly starts aging faster, but the individual rate of change in different body systems.
The initial work from Stanford University had several important points. limitations, which the authors themselves pointed out even before the appearance of the editorial disclaimer.
Only 108 people participated in the study, and there were only eight participants in the group from 25 to 40 years old. The median follow-up period was only 1.7 years, although the longest period was 6.8 years.
Therefore, much of the age difference was actually determined by comparing people of different ages, rather than by observing how the same participants reached their 40s, 50s, or 60s. The authors directly pointed out this feature of the work and the limitation of extrapolation of the results to the entire population.
After the editorial disclaimer of Nature Aging, this limitation becomes especially significant.
The body of research does not yet allow us to name a universal age at which the body of each person experiences a certain "jump of aging".
Various studies revealed the most pronounced changes at around 34, 44, 50, 60, 63 and 78 years, and the result depended on the studied molecules, tissues, methods of analysis and the composition of the participants.
At the same time, a pattern that is repeated in several independent works indicates two rather broad periods of increased biological restructuring: the middle of life — approximately 45–55 years — and the beginning of old age after 60 years.
Therefore, the most correct conclusion of modern research is not that a person necessarily “jumps” in a specific year of life, but that the rate of molecular and functional aging of various body systems changes over time and differs significantly between people.
An additional confirmation of clinical the significance of such an approach is the study of the biological clock: molecular age can differ markedly from calendar age and in a number of large cohorts is associated with the future risk of chronic diseases and mortality.
