The study, run with Nagoya University and published in npj Aging, a Nature Portfolio journal, also found that people with diabetes score older than their calendar age. Craif describes the urinary microRNA aging clock as a world first.
Craif Inc., a bio-AI startup based in Tokyo, said today that it has developed an aging clock that estimates biological age, meaning the degree of aging at the cell level, from microRNA in a single urine sample. The study behind it was published on December 15, 2025 in npj Aging, a Nature Portfolio journal covering aging and healthy lifespan.
The model was built with Nagoya University on urine from 6,331 Japanese people and estimated biological age with an average error of about 4.4 years. Craif describes this as the world's first aging clock based on urinary microRNA.
What the study found
- A model built on urinary microRNA estimated biological age with an average error of about 4.4 years. Craif says this approaches the accuracy of DNA methylation testing, which it calls the mainstream method to date, from a non-invasive and lower cost sample.
- The analysis covered microRNA patterns in 6,331 Japanese people. Craif reports high reproducibility when the model was checked in an independent cohort.
- A number of microRNAs closely associated with aging were identified, including miR-34a-5p and miR-146a-5p.
- Delta age, the gap between estimated biological age and calendar age, was significantly higher in people with diabetes. Craif says this suggests diabetes may act as a factor that speeds up aging in the body.
- The test needs only a urine sample. Craif says it could in future be applied to health management at home.
What the aging clock does not claim
The aging clock estimates biological age. It is not a cancer test, it does not screen for or detect any disease, and it does not diagnose anything. The diabetes finding is an association between a higher delta age and the presence of diabetes in this cohort, not evidence that the clock identifies diabetes or predicts who will develop it. The output is a model estimate carrying an average error of about 4.4 years, not a measurement of a person's true age.
Why biological age is worth measuring
Aging is the underlying risk factor for many chronic diseases, including cancer, cardiovascular disease, diabetes and dementia, so an objective measure of aging sits at the center of preventive medicine. Until now, knowing how far aging has actually progressed inside the body has required a blood draw or a test at a specialist medical institution, which puts it out of reach of routine use.
Because a urine sample is something people produce every day, Craif says a urinary clock allows repeated assessment with minimal burden on the person being tested. Craif also says it could serve as a way to test the link between biological age and disease risk in large datasets, as an indicator of accelerated aging in lifestyle-related and age-related disease, and as a way to quantify whether a medical or lifestyle intervention is working when biological age is tracked over time.
The Japanese release states that the market for anti-aging and healthy-lifespan extension is forecast to grow to tens of trillions of yen by 2030.
What delta age means
Calendar age counts the years since a person was born. Biological age is an estimate, from molecular measurements, of how worn or how well functioning that person's cells and organs are. Two people who are both 50 can differ: one may look closer to 40 at the cell level, another closer to 60.
Craif defines delta age as biological age minus calendar age. A large positive delta age means aging inside the body has run ahead of the calendar. A negative value means the person is in better shape than others of the same age. In this study delta age was significantly higher in people with diabetes, which Craif says points to diabetes acting through mechanisms such as vascular damage and chronic inflammation to push aging forward.
Publication information
- Title: A urinary microRNA aging clock accurately predicts biological age
- Journal: npj Aging
- Published: December 15, 2025
- Authors: Milos Havelka, Atsushi Satomura, Hiroki Yamaguchi, Akira Cortal, Yoriko Ando, Motoki Mikami, Mika Mizunuma, Yuki Ichikawa
About Craif
Craif is a bio-AI startup founded in 2018 that works on early detection of cancer. It combines AI with its own analytical platform, NANO IP (NANO Intelligence Platform), which detects a range of biomarkers including DNA and microRNA from biofluids such as urine, to develop tests intended to make very early cancer detection, early treatment, and an early return to daily life possible. Craif's stated vision, in its own English wording, is to help people live longer, healthier lives.
Company details
- Company: Craif Inc.
- Representative: Ryuichi Onose, Representative Director and CEO
- Founded: May 2018
- Business: research and development of next-generation tests for early detection of disease and personalized medicine, centered on cancer, and provision of the miSignal urine cancer risk test
- Headquarters: THE PORTAL iidabashi B1F, 8-30 Shin-Ogawamachi, Shinjuku-ku, Tokyo
URL: https://craif.com/
