According to Experts.news, the human body probably does not age at a constant rate: several major studies in recent years have identified periods of particularly intense changes in proteins, metabolites, the immune system and other molecular indicators during middle and old age. However, the widely held view of two specific ‘ageing spikes’ at around 44 and 60 years of age now needs to be reconsidered.
A study by researchers at Stanford University, published in the journal *Nature Aging* on 14 August 2024, analysed 108 people aged between 25 and 75. The researchers collected blood, microbiome samples and other biomaterials every few months and examined ten types of molecular data simultaneously – ranging from transcriptomics and proteomics to metabolomics, lipidomics and cytokines. Initial analysis identified two distinct periods of change, occurring at around 44 and 60 years of age.
Around the age of 44, processes related to lipid and alcohol metabolism, the cardiovascular system, the skin and muscles changed particularly noticeably. Around the age of 60, the authors observed changes in immune regulation, carbohydrate metabolism, kidney function and a number of metabolic processes.
However, on 15 July 2026, *Nature Aging* added a special editorial note to the publication. Following further scrutiny by the authors and independent researchers, the reliability of the part of the analysis used to identify peaks in molecular changes during specific age periods has been called into question. The authors, together with the editorial team, are continuing to assess the scale of the problem and possible corrections.
This means that the claim that ‘humans age rapidly at precisely 44 and 60 years of age’ cannot currently be regarded as a firmly established scientific fact.
However, the more general conclusion that biological ageing may occur unevenly is supported by a number of independent studies.
As far back as 2019, scientists, who analysed 2,925 blood plasma proteins in 4,263 people aged between 18 and 95, discovered non-linear changes in the proteome and three periods of intensified remodelling — at approximately 34, 60 and 78 years of age. The study was published in *Nature Medicine*.
The authors of the latter study attributed the difference between the first peak and the findings of the later Stanford study, in particular, to different methods of protein measurement and a different age range of participants. However, both studies pointed to pronounced changes at around the age of 60.
Another important finding emerged in 2025.
A study published in the journal *Cell* created a large-scale proteomic atlas of ageing in various human tissues. The researchers found that changes in the protein composition of most of the organs studied accelerated noticeably from around the age of 50, particularly between the ages of 45 and 55. Blood vessels proved to be among the tissues most sensitive to ageing.
This study therefore also supports the idea of a period of accelerated biological reorganisation in middle age, although it does not specifically confirm the age of 44.
The authors developed separate ‘proteomic clocks’ for different tissues, as organs within the same individual can age at different rates. This is consistent with the current understanding of biological age as a heterogeneous process, during which the condition of the heart, blood vessels, liver, kidneys or other systems does not necessarily correspond to a person’s chronological age.
Further data became available as early as 2026. In March, the researchers published an analysis of plasma proteins from 50,506 UK Biobank participants in the journal *Cell Metabolism*. They examined 2,911 proteins and identified 1,339 proteins associated with signs of frailty.
When analysing age-related changes, the scientists observed a biphasic pattern: the most pronounced periods of proteomic reorganisation associated with frailty were observed at around 50 and 63 years of age.
This is particularly interesting when compared with previous studies: whilst the exact figures vary, several independent datasets again point to an average age of around 45–55 years and the period after the age of 60 as stages of significant molecular reorganisation in the body.
A separate large-scale study in *Nature Medicine* analysed data from 45,441 UK Biobank participants and 2,897 plasma proteins, after which the researchers constructed a proteomic ‘ageing clock’.
It emerged that the difference between proteomic and chronological age is associated with subsequent risk of disease and death. A higher estimated biological age was associated, in particular, with an increased risk of developing dementia, Alzheimer’s disease, chronic kidney disease, ischaemic heart disease and type 2 diabetes, even after taking into account a number of other risk factors.
The study supports a broader concept: it is not so much a specific birthday, after which a person supposedly begins to age more rapidly, that matters, but rather the individual rate of change across the body’s various systems.
The original study by Stanford University had several significant limitations, which the authors themselves had pointed out even before the editorial caveat was issued.
A total of just 108 people took part in the study, of whom only eight were in the 25 to 40 age group. The median follow-up period was