Two 'Forever Chemicals' Accelerate Biological Aging - and Middle-Aged Men Are Most Vulnerable

Per- and polyfluoroalkyl substances have been called forever chemicals for a simple reason: they do not break down. The carbon-fluorine bonds that make them so useful in non-stick cookware, water-resistant clothing, firefighting foam, and food packaging are among the strongest in organic chemistry. What makes them industrially valuable makes them environmentally persistent - and potentially dangerous to human health.

A new study published in Frontiers in Aging adds biological aging to the list of health concerns associated with specific PFAS compounds. The research, led by Dr. Xiangwei Li at Shanghai Jiao Tong University School of Medicine, found that two particular chemicals in the PFAS family - perfluorononanoic acid (PFNA) and perfluorooctanesulfonamide (PFOSA) - appear to accelerate epigenetic aging, with middle-aged men showing the most pronounced effect.

Measuring age at the molecular level

Biological aging is not synonymous with chronological aging. The cells of a 50-year-old might show epigenetic patterns typical of a 45-year-old or a 55-year-old, depending on a range of factors including genetics, lifestyle, and environmental exposures. Epigenetic clocks - molecular tools that measure patterns of DNA methylation across the genome - allow researchers to estimate biological age independently of birth certificates and compare it to actual age. A gap between the two, where biological age exceeds chronological age, is associated with higher risk of age-related diseases and earlier mortality.

The study analyzed associations between blood PFAS concentrations and epigenetic clock measurements in a study population, finding that higher levels of PFNA and PFOSA were associated with faster epigenetic aging. The effect was not uniform across the population: middle-aged men showed the strongest association, a finding that the researchers describe as suggesting this demographic is particularly vulnerable to the aging effects of these specific chemicals.

Not all PFAS are the same - and newer is not safer

The PFAS family encompasses thousands of synthetic chemicals. Some, like perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), have been targeted for global elimination under the 2001 Stockholm Convention on Persistent Organic Pollutants and have been largely phased out of production and use in many countries. Others - including PFNA and PFOSA, the compounds flagged in this study - are among the alternatives that entered wider use as the legacy compounds were restricted.

PFAS exposure is also evolving in new directions. The rapid expansion of AI data centers has driven demand for specialized cooling and insulating materials, some of which use newer PFAS compounds. The industrial logic has been consistent: when one PFAS compound is restricted, substitute it with a chemically similar compound that has not yet been regulated. The health and environmental profile of the substitute is often poorly characterized at the time of adoption.

The study directly challenges the assumption that newer PFAS alternatives carry lower risks. Dr. Li stated explicitly that some newer PFAS alternatives are not necessarily low-risk replacements and warrant serious attention from regulators and researchers.

Mechanisms and uncertainties

The study demonstrates an association between PFNA and PFOSA exposure and accelerated epigenetic aging. It does not establish a confirmed causal mechanism. Several plausible pathways exist: PFAS are known to interfere with hormonal signaling, inflammatory processes, and mitochondrial function - all of which influence epigenetic aging rates. But the specific molecular chain from PFAS exposure to DNA methylation changes remains to be characterized.

Epidemiological studies of this kind face inherent limitations around confounding. People with high PFAS exposures may differ from those with low exposures in other ways - diet, occupation, geographic location - that also affect aging rates. Statistical controls for known confounders reduce but do not eliminate this concern. The study used available covariates, but unmeasured factors could influence the associations observed.

The question of dose is also important. The study examines naturally occurring variation in blood PFAS levels across a population, not experimental exposures at controlled doses. Understanding the dose-response relationship - whether the effect is linear, whether there is a threshold, whether it varies by age or sex in systematic ways - requires additional investigation.

Regulatory context

The European Union is currently advancing plans to restrict PFAS as a class, rather than addressing individual compounds one at a time. This approach is designed to prevent the substitution problem - the cycle in which banning specific PFAS simply accelerates the adoption of unstudied alternatives. The findings from this study, linking two specific newer PFAS alternatives to biological aging effects, provide evidence directly relevant to that regulatory debate.

PFAS contamination is already widespread. These chemicals are detectable in drinking water sources, agricultural soils, and the blood of people across the world, including populations with no direct occupational exposure. The question is no longer whether PFAS exposure is universal - it largely is - but which specific compounds, at what concentrations, cause what kinds of harm to whom.