A graph showing the distribution of 27 subjects based on four age-linked metabolites as an index

The graph above shows that the age of a person can be roughly identified by measuring only four metabolites in their saliva. The blue dots each represent one person in the 27-33 age group, whereas the red dots each represent one person in the 72-80 age group. This figure appeared in the press release “How we age, as told by spit.”