Can you measure your biological age with standard blood markers, such as the PhenoAge test?
Standard blood markers can, via PhenoAge, provide an estimate of your biological age, and that estimate predicts health risks measurably better than chronological age alone. The score is not a definitive measure, but it does provide meaningful information about how quickly your body is ageing.
PhenoAge is a calculation based on standard blood markers such as albumin, creatinine, CRP, glucose and leukocytes. The result predicts mortality: people whose PhenoAge runs faster than their chronological age have a 1.7 to 2.3 times higher risk of death per standard unit of acceleration. That is statistically meaningful, and the test reveals genuine biological differences.
That said, PhenoAge does not measure exactly the same thing as DNA methylation clocks, the 'gold standard' for biological ageing. The correspondence between the two types of clocks is moderate: the correlation ranges between 0.1 and 0.4. The two methods complement each other but are neither interchangeable nor equivalent.
PhenoAge has also been studied as a predictor of disease risk. People with an accelerated biological age had rheumatoid arthritis more than 2.7 times as often, and a 1.8 times higher risk of death from psoriasis. These associations are strikingly large, but because the data come from population studies in which participants were followed over time, it cannot be proven that accelerated biological age is the cause.
Certain factors are associated with higher PhenoAge scores. An unfavourable blood lipid profile (higher triglycerides and lower HDL) was associated with an average of nearly 2 years of additional biological ageing. Iron supplementation above 45 mg per day also showed an association with acceleration, whereas iron from regular food did not. Long-term obesity from childhood onwards was associated with higher inflammatory markers and other ageing markers even at a young age.
Conversely, a high vitamin D level combined with sufficient physical activity was associated with a biological age that was, on average, just over a year lower. Separately, the effect of each was roughly half of that combined figure. Whether a vitamin D supplement achieves the same result as a naturally high level cannot be determined from these studies.
This answer is based on multiple studies in which participants were followed over time or examined at a single point in time; no study is able to establish cause and effect here. No study compared participants randomly assigned to a group with or without a PhenoAge intervention. Correlations with DNA methylation clocks have been measured, but the added clinical value of PhenoAge over conventional risk factors has not yet been systematically compared. The evidence on what PhenoAge predicts is reasonably consistent; the evidence on what influences the score is thinner and based on cross-sectional research.