Here’s what we’ll cover in this blog post:
- What biological aging tests measure
- How organ aging may be more important
- Recent studies on the importance of brain aging
- How to measure organ age
In my 12 years as a longevity scientist, I’ve explored the cellular and molecular levers that drive and slow metabolic disease, cognitive decline, muscle loss, and chronic inflammation.
One lesson has reshaped how I think about aging: we’ve been measuring it the wrong way.
Chronological age, or the number of birthdays you’ve had, can be very misleading in terms of reflecting your true functional health. Biological age is far more revealing. And now, the geroscience field is taking it a step further: it’s not not just about your biological age, but the biological ages of each of your organs. That’s where longevity gets personal—and actionable.
Why Isn’t Chronological Age Enough?
Aging is not a number on your birth certificate. It’s a biological process determined by how well your organs function. Chronological age counts birthdays, but biological age reveals functional health.
Two people can be 60, but if one is running marathons while the other is struggling to climb a flight of stairs, their health profiles may be drastically different. Biological age tests were developed to capture this difference.
The problem is that many biological age tests just give you a number, without further biological insight into what’s actually going on inside the body. That’s like getting a “check engine” light without a mechanic’s insight: you don’t know if it’s the battery, the transmission, or a faulty spark plug.
But a 10-year-old car may drive like new, or feel like it’s on the verge of breaking down, depending on how well its parts are maintained. Your body works the same way, and your organs don’t all wear down evenly.
In reality, your brain, heart, immune system, gut, and other organs each have their own biological clock. Some tick slowly, others race ahead. That’s the type of information we need to take action, like having a car dashboard for your health
Knowing how your individual organs are aging can change how you manage risk factors and protect your future health. And that’s exactly what longevity scientists are building.
How Are Scientists Measuring Organ Age?
In a landmark study, researchers tracked 2,916 proteins in the blood across tens of thousands of participants,grouping them based on each organ they came from. Each organ sheds a unique protein into the blood, which AI models analyze to determine if the organ is younger or older than their calendar age.
Researchers analyzed eleven major systems: brain, heart, immune system, lung, liver, kidney, pancreas, intestine, muscle, fat, and vasculature. This organ-by-organ profiling allows us to see which systems are thriving and which need attention, long before disease develops.
What Did the Study Show?
The study followed 44,498 adults (ages 40–70) for up to 17 years. Researchers found a clear pattern: the older an organ’s biological age, the higher the risk of disease and death.
Brain age was by far the strongest predictor of future health outcomes. A brain with a higher biological age tripled the risk of Alzheimer’s disease, regardless of genetic risk status. On the other hand, lower brain age cut the risk of Alzheimer’s by 74%. This is critical, suggesting that changes in brain proteins drive risk. This is also independent of one of the strongest risk factors for Alzheimer’s: the APOE4 gene.
Which Organs Most Influence Disease Risk?
Older organs were tied to specific diseases:
- Heart: +75–83% risk of atrial fibrillation and heart failure
- Kidneys: +66–80% risk of chronic kidney disease
- Lungs: +39% risk of COPD
- Brain: +300% risk of Alzheimer’s
That last statistic is the most striking: brain age can be as strong a signal of Alzheimer’s risk than our most well known genetic risk factor. This is critical because, unlike your genes, your organ age is modifiable.
Among the most empowering findings from the study is that youthful brains and immune systems reduced mortality risk by more than 56%, while youthful intestines protected against diabetes.
When both the brain and immune system showed lower biological age, individuals had the lowest death risk of all participants. In practice, this means lifestyle, supplement, or pharmacological strategies that protect the brain and immune system could have disproportionate returns on healthspan.
How Does Having Multiple Aged Organs Affect Longevity?
The more aged organs you have, the higher the mortality risk:
- 2–3 aged organs → +230% increased risk of death
- 5–7 aged organs → +450%
- 8+ aged organs → +830%
On the other end of the spectrum, having even 2–4 organs with a lower biological age was found to be protective against multiple diseases, including kidney disease and osteoarthritis. It’s a powerful case for early testing and targeted action, before things get out of hand.
Why Is the Brain Aging So Important?
Biological aging is modifiable. Your organs age at different speeds, and knowing which are accelerating can help guide you to the most impactful interventions for you—whether that’s diet, exercise, supplements, or pharmaceuticals.
I think of the brain as the control tower of aging. If the brain maintains efficient regulation of hormones, inflammation, and metabolism, it slows the biological clocks of other systems. That’s why interventions targeting brain health could yield the greatest longevity benefits.
The future of longevity medicine will feature a dashboard of organ ages, like a car diagnostic scan, showing your brain, heart, gut, and immune health in real time. That’s when longevity care evolves into precision longevity medicine: personalized towards each individual’s unique aging trajectory.
If you want to get a sense of how fast your organs are aging, try iollo. This emerging biological age test now makes organ-specific insights possible with a single blood draw. From there, our medical experts can help you find the right medical or lifestyle choices for you. Alternatively, you can try science-backed longevity interventions to target unique hallmarks of aging, like Methylene Blue for brain aging or Low Dose Naltrexone (LDN) for inflammation.
The earlier you start, the greater the benefits. By testing your biological and organ age today, you can get actionable insights that help you build a longevity strategy that is as unique as your organ aging profile. If you’re looking to extend not just how long you live, but how well you live, these options empower you to take control of your health with targeted guidance to protect the systems that matter most for your future health.
Note: The above statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.