From DNA methylation to DunedinPACE: compact explanations for the most important terms around BioAge tests, epigenetic clocks and longevity diagnostics.
B
Biological age core term
Estimate of the functional state of cells from biomarkers (DNA methylation, glycan profile, blood markers). Can differ several years from chronological age.
Bisulfite conversion lab
Chemical treatment that converts unmethylated cytosines to uracil while leaving methylated ones intact. Prerequisite for most methylation assays.
C
CpG site genomics
Cytosine-guanine dinucleotide in the DNA sequence. At these sites cytosine can be methylated. Epigenetic clocks evaluate hundreds to thousands of these sites.
Chronological age reference
Age by birth date. Distinct from biological age, which reflects cellular state.
D
DNA methylation epigenetics
Attachment of a methyl group to cytosine bases — alters gene activity without changing the sequence. Foundation of all epigenetic clocks.
DunedinPACE clock
Clock from the Dunedin cohort (Belsky 2022). Measures pace of aging rather than age itself: 1.0 = standard, 0.85 = aging slower.
E
Epigenetics discipline
Study of gene-activity regulation beyond the DNA sequence (methylation, histone modifications, chromatin structure). One of the 12 hallmarks of aging.
Epigenetic clock diagnostic
Algorithm that calculates a biological age from DNA methylation patterns. Best known: Horvath 2013, Hannum 2013, PhenoAge 2018, GrimAge 2019, DunedinPACE 2022.
F
Fingerstick sampling
Lancet prick on the fingertip for capillary blood drops. Standard method for dried-blood kits.
G
GlycanAge test
BioAge test based on IgG glycan profile. Responsive to chronic inflammation (inflammaging) and therefore to lifestyle change.
GrimAge clock
Epigenetic clock (Lu, Horvath 2019). Trained on mortality prediction. Strongly predictive of disease and death.
H
Hannum clock clock
Epigenetic clock published 2013 (Hannum et al.). 71 CpG sites. Early milestone of methylation-based age estimation.
Horvath clock clock
Published 2013 by Steve Horvath (UCLA). 353 CpG sites, tissue-spanning. Reference point of the field.
I
IgG glycans immunology
Sugar chains on immunoglobulin G. Their profile shifts with age and chronic inflammation. Foundation of GlycanAge.
InnerAge product
Algorithmically calculated "biological age" from InsideTracker based on classic lab markers.
Illumina Methylation EPIC lab
Standard array used by most commercial epigenetic clocks — over 850,000 CpG sites.
L
Lifespan concept
Total years lived. Distinct from healthspan = years lived in good health.
Levine, Morgan researcher
Developed PhenoAge (2018), one of the most influential clocks. Now Altos Labs / Yale.
M
Methylation array lab
Chip for simultaneously measuring many CpG methylations. See Illumina EPIC.
Multi-omics method
Combination of multiple molecular data layers (genome + methylome + metabolome + proteome). Foundation of clocks like OMICmAge.
O
OMICmAge clock
TruDiagnostic clock (2024) on a multi-omics basis. Integrates methylation with metabolomics and clinical markers.
Omega-3 index biomarker
EPA+DHA share in erythrocyte membranes in %. Index above 8 % associated with substantially reduced cardiovascular risk.
P
PACE concept
Pace of aging. Instead of an absolute value, the rate of aging is measured. DunedinPACE is the best-known implementation.
PhenoAge clock
Clock (Levine 2018) combining DNA methylation with clinical lab markers (albumin, creatinine, CRP).
R
Reproducibility quality criterion
How consistently does a test return the same result on the same sample? Epigenetic clocks typically have standard deviations of 1 – 3 years.
S
Saliva sample sampling
Convenient alternative to blood. For DNA methylation, slightly less precise because cell-type composition varies more.
SNP genomics
Single nucleotide polymorphism. Single-base variation in DNA. Distinct from methylation: SNPs are sequence variants, methylation is reversible and epigenetic.
T
Telomere length biomarker
Length of DNA protective caps at chromosome ends. Originally popular as an age marker, methodologically eclipsed by epigenetic clocks today.
Dried blood sampling
Fingerstick blood dried on a filter card. Stable for transport and storage.
TruDiagnostic provider
US provider of epigenetic tests. TruAge Complete (OMICmAge + GrimAge + PACE) and TruAge PACE single.
V
Validation science
Demonstration that a test actually measures what it claims to. For BioAge clocks, often via mortality correlation in large cohorts.
Venous blood draw sampling
Blood drawn from an arm vein by trained personnel. Required for functional test panels (InsideTracker Ultimate).