According to Experts.news, the human body likely does not age at a constant rate: several large-scale studies in recent years have identified periods of particularly intense restructuring of proteins, metabolites, the immune system, and other molecular markers during middle and old age. However, the widely held view of two specific “aging spikes” at approximately ages 44 and 60 now needs to be revised.
A study by Stanford University researchers, published in the journal *Nature Aging* on August 14, 2024, analyzed 108 individuals aged 25 to 75. The researchers collected blood, microbiome samples, and other biomaterials every few months and examined ten types of molecular data—ranging from transcriptomics and proteomics to metabolomics, lipidomics, and cytokines. Initial analysis revealed two distinct periods of change, occurring around ages 44 and 60.
Around age 44, processes related to lipid and alcohol metabolism, the cardiovascular system, skin, and muscles changed particularly noticeably. Around age 60, 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 note to the publication. Following further review by the authors and independent researchers, the reliability of the portion of the analysis used to identify peaks in molecular changes during specific age periods was called into question. The authors, together with the editorial board, are continuing to assess the scope of the issue and possible corrections.
This means that the claim that “humans age rapidly specifically at ages 44 and 60” cannot currently be considered a reliably established scientific fact.
At the same time, the more general conclusion that biological aging may occur unevenly is supported by a number of independent studies.
As early as 2019, scientists who studied 2,925 blood plasma proteins in 4,263 individuals aged 18 to 95 identified nonlinear changes in the proteome and three periods of intensified remodeling—at approximately 34, 60, and 78 years of age. The study was published in *Nature Medicine*.
The authors of the later Stanford study attributed the discrepancy between the first peak and their findings to, among other things, different protein measurement methods and a different age range of participants. However, both studies pointed to pronounced changes 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 aging in various human tissues. The scientists found that changes in the protein composition of most of the organs studied accelerated noticeably around the age of 50, particularly between the ages of 45 and 55. Blood vessels proved to be among the tissues most sensitive to age.
Thus, this work also supports the idea of 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 organs within a single person 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.
Additional data became available as early as 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 identified 1,339 proteins associated with signs of frailty.
When analyzing age-related changes, the scientists observed a two-phase pattern: the most pronounced periods of proteomic remodeling associated with frailty occurred around ages 50 and 63.
This is particularly interesting when compared to previous studies: while the exact figures vary, several independent datasets again point to an average age of about 45–55 years and the period after age 60 as stages of significant molecular remodeling in the body.
A separate large-scale study in *Nature Medicine* analyzed data from 45,441 UK Biobank participants and 2,897 plasma proteins, after which the researchers constructed proteomic “aging clocks.”
It turned out that the difference between proteomic and chronological age is associated with the subsequent risk of disease and death. A higher calculated biological age was associated, in particular, with an increased risk of dementia, Alzheimer’s disease, chronic kidney disease, ischemic heart disease, and type 2 diabetes—even after accounting for a range of other risk factors.
The study confirms a broader concept: what matters is not so much a specific birthday—after which a person supposedly begins to age faster—as the individual rate of change in various bodily systems.
The initial study from Stanford University had several significant limitations, which the authors themselves pointed out even before the editorial note was published.
Only 108 people participated in the study, and there were just eight participants in the 25-to-40-year-old group. The median follow-up period was only 1.7 years, although the longest period reached 6.8 years.
Therefore, a significant portion of the age-related differences was actually determined by comparing people of different ages, rather than by observing how the same participants reached ages 40, 50, or 60. The authors explicitly pointed out this aspect of the study and the limitations of extrapolating the results to the entire population.
Following an editorial note in *Nature Aging*, this limitation becomes particularly significant.
The body of research does not yet allow us to identify a universal age at which every person’s body experiences a specific “ageing leap.”
Various studies have identified the most pronounced changes at approximately 34, 44, 50, 60, 63, and 78 years of age, with the results depending on the molecules and tissues studied, the analytical methods used, and the composition of the study participants.
However, a pattern that recurs in several independent studies points to two fairly broad periods of heightened biological restructuring: midlife—approximately ages 45–55—and the onset of old age after age 60.
Therefore, the most accurate conclusion from current research is not that a person necessarily “ages in a sudden leap” at a specific year of life, but rather that the rate of molecular and functional aging of various bodily systems changes over time and varies significantly among individuals.
Studies of the biological clock provide further confirmation of the clinical significance of this approach: molecular age can differ markedly from chronological age and, in several large cohorts, is associated with future risks of chronic diseases and mortality.
