Highlights: 

  • Epigenetic clocks have great predictive power in determining the probability of human disease and mortality risks. 
  • While Bryan Johnson has reduced his epigenetic age, suggesting potential improvements in longevity, his calculation for reducing his pace of aging by 31 years is unsubstantiated. 

Bryan Johnson has spent millions of dollars to devise an anti-aging regimen called Blueprint that he claims slowed the pace of his aging by the equivalent of 31 years. However, Dr. Morgan Levine, who pioneered the development of advanced epigenetic clocks, says otherwise. 

In a tweet, Dr. Levine said that epigenetic clocks determine aging rates and are not measured in units of years. Therefore, Johnson cannot say that he has reduced his pace of aging by 31 years. She also says that epigenetic clocks are a “single imperfect estimate of aging, not a direct measure… and pace [of aging] is not meant to be used in reference to an age.”

What Are Epigenetic Clocks? 

As we age, a multitude of changes occur to our organs, tissues, and cells, including epigenetic modifications. Unlike genetic modifications, which alter the sequence of our DNA, epigenetic modifications reconfigure the three-dimensional structure of our DNA to turn genes on and off. The most investigated epigenetic modification is called methylation, whereby a chemical structure called a methyl group is attached to specific regions of our DNA. 

Epigenetic clocks measure age-related changes in DNA methylation. The first epigenetic clocks (e.g., Hovarth’s and Hannum’s clocks) were found to predict someone’s chronological age — the years an individual has lived. Subsequently, newer clocks have since been developed that can predict mortality and disease risks. Thus, measuring one’s DNA methylation patterns with epigenetic clocks can predict someone’s age, the likelihood they will succumb to disease, and how long they might live.  

The Problem with Bryan Johnson’s Age-Reversal Claim 

Epigenetic clocks were initially developed to estimate chronological age. However, it was found that epigenetic age deviates from chronological age in some individuals. Thus, age acceleration refers to when one’s epigenetic age is older than their chronological age, and deceleration refers to when one’s epigenetic age is younger than their chronological age. Research has shown that several interventions, including diet, exercise, and various supplements can reduce one’s epigenetic age, suggesting age reversal. 

The specific epigenetic clock that Bryan Johnson uses is called DunedinPACE, which is based on a study done on participants in Dunedin, New Zealand. With this clock, Johnson has determined that his average pace of aging is 0.66 years per year. That is, 0.66 years of epigenetic aging per chronological year. In other words, his rate of aging, or his epigenetic age is reduced relative to his chronological age, suggesting age reversal. 

How Johnson calculated his 31-year age reversal based on his average epigenetic age is unclear. If applying his rate of aging to his chronological age, 47, we obtain 31 years (47 x 0.66 = 31.02), which may be where he got this number from. However, it makes more logical sense that he has reduced his pace of aging by 16 years (47 – 31.02 = 15.98). 

What Dr. Levine points out is that a rate of aging cannot be applied to one’s entire lifespan because aging progresses on a trajectory that manifests later in life. In contrast, epigenetic aging clocks are capturing one moment in time. It’s true that epigenetic age has predictive power and Johnson’s epigenetic pace of aging likely reflects a lower risk of mortality and disease, but this does not mean that he has reversed his pace of aging by 31 years. 

Are Bryan Johnson’s Claims Just Hyped?

Through his Blueprint protocol, Johnson has reduced his epigenetic age, which according to the latest science, is predictive of mortality and disease. His epigenetic age likely reflects his health and can be used as an overall indicator of his potential longevity. Thus, while his 31-year pace of aging reduction claim appears unsubstantiated and overhyped, his reduction in epigenetic aging holds scientific validity. Importantly, while Johnson goes through great lengths to reduce his epigenetic age, he admits that diet, exercise, and good sleep are probably the main reasons for his improved longevity biomarkers.