AI technology can now reveal your true “biological age” from just five drops of blood. The state of the art system can work out how well your body is coping with the passage of time, say Japanese scientists. The test could be used to help people live longer, healthier lives.

Researchers at Osaka University believe they have found a way to quantify why some people seem to defy ageing and look younger than their peers – despite being the same age. By incorporating hormone metabolism pathways into an AI-driven model, the Japanese team have developed a new system to estimate a person’s biological age: a measure of how well their body has aged, rather than just counting the years since birth.

Using just five drops of blood, the new method analyses 22 key steroids and their interactions to provide a more precise health assessment. The team say their breakthrough study, published in the journal Science Advances, offers a potential step forward in personalised health management, allowing for earlier detection of age-related health risks and tailored interventions.They explained that ageing isn’t just about the number of years we’ve lived, it’s also shaped by genetics, lifestyle, and environmental factors.

Study co-first author Dr Qiuyi Wang says traditional methods for estimating biological age rely on broad biomarkers, such as DNA methylation or protein levels, but those approaches often overlook the “intricate” hormonal networks that regulate the body’s internal balance.

Dr Wang said: “Our bodies rely on hormones to maintain homeostasis, so we thought, why not use these as key indicators of ageing?” To test the idea, the research team focused on steroid hormones, which play a crucial role in metabolism, immune function, and stress response.

The researchers developed a deep neural network (DNN) model that incorporates steroid metabolism pathways, making it the first AI model to explicitly account for the interactions between different steroid molecules. Instead of looking at absolute steroid levels – which can vary widely between people – the model examines steroid ratios, providing a more personalised and accurate assessment of biological age.

Co-first author Dr Zi Wang said: “Our approach reduces the noise caused by individual steroid level differences and allows the model to focus on meaningful patterns. The model was trained on blood samples from hundreds of individuals, revealing that biological age differences tend to widen as people get older—an effect the researchers liken to a river widening as it flows downstream.”

The research team said one of the study’s most striking findings involves cortisol, a steroid hormone commonly associated with stress. The team found that when cortisol levels doubled, biological age increased by around 50%.They say it suggests that chronic stress could accelerate ageing at a biochemical level, reinforcing the importance of stress management in maintaining long-term health.

Study corresponding author Professor Toshifumi Takao said: “Stress is often discussed in general terms, but our findings provide concrete evidence that it has a measurable impact on biological ageing.”

The researchers believe that AI-powered biological age model could pave the way for more personalised health monitoring. They said future applications may include early disease detection, customised wellness programmes, and even lifestyle recommendations tailored to slow down ageing.

Dr Zi Wang added: “This is just the beginning. By expanding our dataset and incorporating additional biological markers, we hope to refine the model further and unlock deeper insights into the mechanisms of ageing.”

Dr Wang said that ongoing advancements in AI and biomedical research make accurately measuring – and even slowing – biological ageing is becoming increasingly feasible.