Bryan Johnson's biological age claims, explained by the scientist behind DunedinPACE and PhenoAge

This was an expert explanation, not a new study with human volunteers. The scientist discussed biological age, an estimate of how old someone’s body seems based on health measures, and aging clocks, computer tools that combine these measures. These tests can predict health risks across large groups, but they are not precise proof of one person’s true age or future lifespan. The explanation also noted that short-term changes in blood tests may reflect illness, diet, exercise, or measurement noise.

What this means for you: Do not buy a supplement or treatment just because it claims to lower your biological age. These tests may be useful for research, but they do not yet prove that a product will help you live longer.