There is no scientific evidence that autistic people age more slowly. In fact, most biological markers point in the opposite direction: autistic individuals show signs of accelerated aging at the cellular and brain level. But this question comes up often for a reason. Many autistic people are told they look younger than their age, and there are plausible explanations for that perception, even as the underlying biology tells a different story.
What Biological Aging Markers Actually Show
Several lines of research suggest that autism is associated with faster, not slower, biological aging. A 2023 study using Mendelian randomization found that autistic individuals have significantly shorter telomeres, the protective caps on chromosomes that shorten as cells divide and age. Shorter telomeres are one of the most established markers of accelerated biological aging. The researchers attributed this partly to the chronic stress that autistic people experience from social isolation, stigma, and lack of support, all of which activate the body’s stress response and speed up telomere loss over time.
At the cellular level, autism is also linked to higher oxidative stress and mitochondrial dysfunction, particularly in the frontal lobe, temporal lobe, and cerebellum. Oxidative stress means the body produces more damaging molecules than its antioxidant defenses can handle, which injures neurons and disrupts energy production. Mitochondria in autistic brains show reduced energy output and increased production of these harmful molecules. Both oxidative stress and mitochondrial dysfunction are hallmarks of aging in any population, and their elevated presence in autism suggests the opposite of slowed aging.
Brain Aging Appears Faster, Not Slower
The brain’s outer layer, the cortex, naturally thins as people get older. In autistic adults, this thinning happens faster. A large cross-sectional study using brain imaging data from over 300 adults (ages 18 to 64) found that autistic individuals showed significantly greater age-related cortical thinning compared to non-autistic adults. The differences were largest in the left temporal lobe, a region important for language processing and social cognition, but also appeared in frontal, parietal, and occipital areas.
A separate epigenetic study looked at brain tissue and found that in autistic adults over 45, the cerebellum showed signs of being biologically older than expected. The epigenetic “clock,” which estimates biological age based on chemical modifications to DNA, showed an age acceleration score of about 5 years ahead in autistic individuals over 45, compared to controls whose cerebellum appeared about 6 years younger than their chronological age. That’s a gap of roughly 11 years in the cerebellum’s apparent biological age between the two groups. In younger adults, this difference wasn’t significant, suggesting the divergence may widen with age.
Why Some Autistic People Look Younger
Despite these biological realities, the perception that autistic people “look young” persists in autism communities and anecdotally. There’s no published study directly measuring perceived age in autistic populations, but a few factors could explain the impression.
One is connective tissue. Autistic people have significantly higher rates of joint hypermobility and connective tissue differences associated with conditions like hypermobile Ehlers-Danlos syndrome. In a large case-control study, 25% of autistic participants reported having velvety skin compared to 14% of non-autistic controls, and 11% reported hyperelastic skin versus 4% of controls. The overall odds of having symptomatic connective tissue signs were nearly five times higher in the autistic group. Velvety, elastic skin can give a smoother, more youthful appearance, which may contribute to the perception of looking younger without reflecting actual slower aging.
Behavioral and social factors likely play a role too. Many autistic adults have different patterns of facial expression, less sun-seeking social behavior, and different lifestyle habits than their neurotypical peers, all of which can influence how old someone appears to others. Looking younger and aging slower biologically are two very different things.
Hormonal Differences Add Complexity
One intriguing finding is that autistic individuals tend to have higher levels of DHEA, a hormone that declines steadily with age in the general population. A meta-analysis of 10 studies found significantly elevated DHEA levels in autistic males. DHEA is sometimes called the “youth hormone” because of its role in maintaining muscle mass, skin health, and cognitive function as people age. Higher baseline DHEA could theoretically buffer some visible effects of aging, but no study has tracked whether this translates into slower physical aging in autistic people over decades. It’s a piece of the puzzle that doesn’t yet connect to a clear picture.
How Autism Traits Change With Age
A longitudinal study from the Waisman Center at the University of Wisconsin tracked autistic individuals over 22 years, from adolescence into the early years of old age. The researchers found that some core autism traits improved over time. Social reciprocity difficulties decreased for those without intellectual disability, and verbal communication challenges lessened regardless of intellectual disability status. This improvement could contribute to the impression that autistic people seem “younger” in middle age, as they may be hitting social and functional milestones later than typical timelines would predict.
However, the trajectory wasn’t uniformly positive. Daily living skills, repetitive behaviors, and social engagement all followed a pattern of improving through early adulthood, plateauing, then worsening from midlife onward. This mirrors and possibly exceeds typical age-related functional decline.
Life Expectancy Tells the Clearest Story
If autistic people aged more slowly, you’d expect them to live longer. The opposite is true. Autistic individuals have a shorter life expectancy than the general population. The causes are complex and not fully understood, but researchers point to lifestyle factors like diet, exercise, and sleep as significant contributors, alongside higher rates of co-occurring health conditions. Chronic stress, metabolic challenges, and barriers to healthcare access all compound over a lifetime.
The gap between perception and biology here is striking. Some autistic people genuinely appear younger than their age, likely because of connective tissue differences, behavioral factors, and possibly hormonal profiles. But beneath the surface, the available evidence consistently points toward accelerated biological aging across multiple systems: shorter telomeres, faster cortical thinning, higher oxidative stress, and reduced life expectancy. Looking young and aging slowly are not the same thing.