The Gold Standard Biomarker for Inflammaging: A Clinical Comparison of hs-CRP, Epigenetic Clocks, and IgG Glycans

Chronic inflammation drives biological aging, but the biomarkers used to measure it are not interchangeable. IgG glycans, complex sugar structures attached to antibodies, offer a measure of active chronic inflammation that changes fast enough to track interventions yet stays stable enough to filter noise, unlike high-sensitivity CRP (a blood marker of acute inflammation) or epigenetic clocks (DNA methylation-based age estimates). 

For a full breakdown of how healthcare providers, functional medicine clinics, and corporate wellness programs can use this biomarker, see our GlycanAge for Healthcare Providers, Functional Medicine Clinics & Corporate Wellness Programs guide. 

What is hs-CRP, and why isn't it a reliable marker of chronic inflammation?

High-sensitivity CRP (hs-CRP) is a blood test that measures C-reactive protein, a liver protein that rises during acute inflammatory episodes, but it was not designed to capture chronic, low-grade inflammation. It is approximately 50% genetically determined, and lifestyle factors like diet, exercise, and smoking, plus a wide range of unrelated diseases, from infections to cancers, all influence the result, which reduces its specificity as a chronic inflammation marker.

Results also vary significantly across different analytical methods, with correlation coefficients often below 0.3, which complicates standardization unless the same lab and technique are used for every measurement on a given patient. hs-CRP takes approximately four weeks to respond to inflammatory stimuli, and existing intervention studies show only minimal effects between measurements when a lifestyle or clinical intervention is introduced, making it poorly suited to detecting whether a targeted health change is working. hs-CRP remains valuable in triage settings, where its high prognostic value for acute severity and outcomes is well established, but it was never built to answer the question "is my chronic inflammation changing over time."

What are epigenetic clocks, and how do they differ from glycan-based biological age tests?

Epigenetic clocks estimate biological age from DNA methylation patterns, chemical modifications to gene expression, and they change over years or even decades rather than months, which limits how actionable they are for tracking a specific intervention. Because methylation reflects historical gene expression, epigenetic and glycan-based clocks frequently do not correlate with each other in the same individual: a person can show accelerated glycan age alongside decelerated epigenetic age, or the reverse. Research comparing different epigenetic clocks against each other found that even a maximum-lifespan clock, a clock built to predict mortality, and a clock built to predict disease onset often fail to correlate with one another, underscoring that no single number fully represents biological aging. 

Glycan-based measurement occupies a different position on the responsiveness spectrum. Changes linked to pharmaceutical or hormonal interventions are typically measurable within 3–4 months, while changes driven by lifestyle interventions such as diet, exercise, or stress management generally take 6–12 months to show measurable movement. Epigenetic clocks, which shift over years to decades, have not demonstrated this same speed of responsiveness.

Does GlycanAge outperform epigenetic clocks at predicting disease and mortality?

In early comparative data presented by Prof. Riccardo Marioni at the Longevity Symposium, from a subset of roughly 1,000 individuals with methylation and glycan measurements, IgG glycan acceleration showed a stronger association with type 2 diabetes than GrimAge, a leading epigenetic clock. The two measures showed broadly similar associations with all-cause mortality. Prof. Marioni noted this mortality comparison was based on a limited number of events (48 cases over 10–15 years of follow-up) and described the analysis as preliminary, not yet statistically finalized.

"GlycanAge actually outperforms, or shows a stronger association with, type 2 diabetes than GrimAge. Both GrimAge and GlycanAge acceleration show similar associations with mortality, but it's important to note this is based on a fairly small number of events, just 48 cases of all-cause mortality over 10 to 15 years of follow-up."

— Prof. Riccardo Marioni, Chair of Molecular Epidemiology of Ageing, University of Edinburgh 

In GlycanAge's internal analysis of the Swedish Adoption/Twin Study of Aging, tracking roughly 600 twins from young adulthood to mortality, individuals with accelerated glycan age showed a significant increase in all-cause mortality.

This finding contributed to Le Couteur, Simpson, and de Cabo describing IgG glycans as a potential "Holy Grail" of biological age measurement in a 2014 commentary responding to the original glycan clock paper, a characterization later supported by a growing body of evidence. The practical takeaway for anyone comparing biomarkers: track whichever clock shows the greatest acceleration for you individually, since that is the signal most likely to reflect your actual health risk and the one most worth acting on. 

Why do IgG glycans qualify as a biomarker of inflammaging specifically?

Inflammaging is the accumulation of low-grade chronic inflammation over time, one of the twelve recognized hallmarks of biological aging. IgG glycosylation, the attachment of glycans to Immunoglobulin G antibodies, acts as a molecular switch between pro-inflammatory and anti-inflammatory antibody function: most IgG molecules lacking terminal sialylation (a specific sugar modification) are pro-inflammatory, while sialylated glycans reduce inflammatory antibody activity. A foundational 2013 study analyzing IgG glycosylation in 5,117 individuals across four European populations found that a composite of just three glycans explained up to 58% of the variance in chronological age, more than established markers like telomere length. Because these age-related changes in glycosylation actively promote inflammation, IgG glycans do not just correlate with aging, they appear to be a mechanistic contributor to it.

How does GlycanAge's repeat-test reliability compare to CRP and epigenetic clocks?

Glycan-based measurement sits in a 'sweet spot': responsive enough to detect genuine biological change as it happens, but stable enough that short-term lapses in a routine don't distort the result. hs-CRP, by contrast, struggles with cross-lab standardization. Correlation coefficients between different analytical methods are often below 0.3, meaning a single patient's results are only comparable if run in the same lab with the same technique every time. Epigenetic clocks change over a timescale of years to decades, which is useful for estimating long-run aging trajectory but not for confirming whether a specific short-term intervention worked. This combination of speed and stability is what makes glycan-based testing usable as a monitoring tool for both individuals and clinicians rather than a one-time snapshot. 

Can glycans predict future disease the way epigenetic clocks and CRP claim to?

IgG glycans are associated with more than 70 conditions, including autoimmunity, cardiovascular disease, cancer, and neurodegeneration, and glycan patterns track with diagnosis, prognosis, and treatment response. Large-scale validation includes a UK cohort of 3,500 individuals and a prospective study of 27,000 people in which glycan patterns were associated with future heart attacks and strokes, later supported by a third replication study. This body of evidence positions IgG glycans as a validated predictive biomarker of aging and a rare example of a commercially available test that can track both biological age and response to lifestyle change in the same measurement. During the COVID-19 pandemic, glycan-based and epigenetic biological age clocks were both proposed as tools for patient risk stratification, since biological age proved more relevant than chronological age in predicting disease severity, with glycan changes previously shown to predict future diabetes and cardiovascular events. 

Do glycans respond to medical interventions like hormone therapy, not just lifestyle changes?

IgG glycans respond to both lifestyle and pharmacological interventions, a distinction that separates them from static genetic tests and slow-moving epigenetic clocks. Published intervention studies span diet, weight loss, exercise, specific supplements, and hormone optimization, with glycans shown to respond across all of these categories. This responsiveness is what allows GlycanAge to support monitoring of whether a hormone replacement therapy protocol, a supplement regimen, or a structured lifestyle change is producing a measurable shift in immune aging, rather than relying on symptom tracking alone. 

"We're all different, there are no two identical individuals, and we have to learn from ourselves. We cannot just take universal advice and apply it to everybody... we have to have a way to monitor ourselves to see whether what we are doing is actually helping or harming us."

— Prof. Gordan Lauc, Professor of Biochemistry and Molecular Biology, University of Zagreb, and Co-Founder & Chief Scientific Officer, GlycanAge

It is a monitoring tool for validating that an intervention is working biologically, not a diagnostic test for any single condition.

If I've already done a CRP panel or an epigenetic clock, do I still need a glycan test?

Yes, hs-CRP, epigenetic clocks, and IgG glycans each capture a different layer of biology, and none fully substitutes for the others. CRP reflects acute inflammatory response and fluctuates too quickly, and too inconsistently across labs, to serve as a chronic inflammation tracker. Epigenetic clocks reflect historical, slow-changing gene expression patterns that can diverge entirely from a person's current inflammatory state, since glycan acceleration and epigenetic acceleration frequently do not correlate in the same individual. IgG glycans fill the gap between these two: they capture active, current chronic inflammation, respond quickly enough to reflect real intervention-driven change, and have shown stronger predictive value than telomere length for age-related variance. Ask your clinician which biomarker, or combination, matches the question you are actually trying to answer: acute status, long-run trajectory, or whether this specific intervention is working right now. 

Understanding where inflammaging fits into your health picture starts with a baseline measurement. Order a GlycanAge test kit to see your Glycan Shield, Glycan Youth, Glycan Mature, Glycan Median, and Glycan Bisection results, then track how they shift over your next retest. 

Order your test kit today.

External sources

• https://pubmed.ncbi.nlm.nih.gov/17211240/ — Wessel J, Moratorio G, Rao F, et al. C-reactive protein, an 'intermediate phenotype' for inflammation: human twin studies reveal heritability... J Hypertens. 2007;25(2):329-340.

• https://pubmed.ncbi.nlm.nih.gov/29149257/ — Belsky DW, Moffitt TE, Cohen AA, Corcoran DL, Levine ME, Prinz JA, Schaefer J, Sugden K, Williams B, Poulton R, Caspi A. Eleven Telomere, Epigenetic Clock, and Biomarker-Composite Quantifications of Biological Aging: Do They Measure the Same Thing? Am J Epidemiol. 2018;187(6):1220-1230.

• https://pubmed.ncbi.nlm.nih.gov/24325897/ — Le Couteur DG, Simpson SJ, de Cabo R. Are glycans the holy grail for biomarkers of aging? (Comment on: Glycans Are a Novel Biomarker of Chronological and Biological Age by Kristic et al.). J Gerontol A Biol Sci Med Sci. 2014;69(7):777-778.

• https://pubmed.ncbi.nlm.nih.gov/24325898/ — Krištić J, Vučković F, Menni C, Klarić L, Keser T, Beceheli I, et al. Glycans are a novel biomarker of chronological and biological ages. J Gerontol A Biol Sci Med Sci. 2014;69(7):779-789. Epub 2013 Dec 10.

• https://pmc.ncbi.nlm.nih.gov/articles/PMC10923145/ — Hoshi RA, Plavša B, Liu Y, Trbojević-Akmačić I, Glynn RJ, Ridker PM, Cummings RD, Gudelj I, Lauc G, Demler OV, Mora S. N-Glycosylation Profiles of Immunoglobulin G and Future Cardiovascular Events. Circ Res. 2024;134(5):e3-e14.