Glycans as Biomarkers of Aging and Age-Related Diseases: A Scientific Overview

Ageing is often described in terms of years, but at a molecular level it plays out through the glycome, the vast and dynamic set of sugar structures attached to proteins throughout the body. Glycan biomarkers of aging capture this complexity directly, tracking how immune-linked glycan structures shift with cellular age, independent of chronological age. Rather than a single number on a lab report, the glycome behaves as an active regulatory layer, one that responds to genetics, environment and cellular stress, and helps explain why biological age can diverge sharply from the date on a birth certificate.

To see how these same sugar structures translate into a practical read on immune health, read Glycans: The Sugars That Reveal Your Biological Age and Immune Health.

Glycans: a regulatory system, not a static marker

Glycans are complex carbohydrate structures attached to proteins and lipids, built enzymatically from combinations of monosaccharides rather than encoded directly in DNA. A single protein backbone can carry many different glycan structures depending on genetics, cellular signalling and environmental exposure at the moment it is assembled, which means glycans integrate a far broader range of biological information than the DNA sequence alone could ever capture. On immunoglobulin G (IgG) antibodies, this glycan attachment shapes how the immune system behaves, altering how antibodies bind their targets and regulate inflammation. Viewed this way, the glycome functions less like a fixed readout and more like a live regulatory system, one that shifts continuously with age, health status and immune activity, rather than a single static diagnostic value.

"Glycosylation is a post-translational modification of proteins. Unlike proteins, whose polypeptide backbone is encoded in DNA, glycans do not have a direct genetic template — we consider them integrators of genetic, epigenetic and environmental information. Because their composition is so responsive to cellular stimuli, they have huge potential as biomarkers of different pathophysiological conditions."

— Dr. Tamara Štambuk, Senior Researcher, Genos Glycoscience Research Laboratory

What drives variation in the glycome

Unlike DNA sequence, glycan structures are not directly inherited as a fixed code. Genome-wide association studies have identified dozens of genes involved in regulating N-glycosylation, including HNF1A, a transcription factor shown to act as a master regulator of plasma protein fucosylation. Because glycosylation genes are themselves subject to epigenetic regulation, the same genetic background can produce different glycan outcomes depending on environmental exposure, smoking status, diet and hormonal state. This layered control, spanning genetic, epigenetic and environmental inputs, is what allows the glycome to respond quickly to physiological change, in contrast to slower-moving biomarkers such as DNA methylation. It is also why glycan biomarkers of aging are described as functional effectors as well as indicators: the glycan structures being measured actively participate in immune regulation rather than simply correlating with it.

Enzymatic glycosylation vs non-enzymatic glycation

Two distinct biochemical processes are often conflated under the umbrella of sugar and ageing, and the distinction matters for interpreting glycan biomarkers correctly. Glycosylation is an enzymatically mediated, tightly regulated process carried out by a network of glycosyltransferases and glycosidases that attach defined glycan structures to specific, conserved sites on a protein. Glycation, by contrast, is a non-enzymatic reaction in which sugars bind randomly to proteins, most familiar in the formation of glycated haemoglobin and advanced glycation end-products under conditions of high blood glucose. Where glycation is essentially random and tends to damage protein structure and function, glycosylation is a controlled modification that fine-tunes it, occurring within the endoplasmic reticulum and Golgi apparatus as part of normal protein synthesis. Glycan biomarkers of aging are built on glycosylation patterns, not glycation, which is why they reflect regulated immune signalling rather than simple, cumulative sugar exposure.

"Glycosylation is the cellular metabolic process of adding sugar chains onto proteins or lipids. Glycation is strictly a chemical reaction, where different activated groups interact with each other and produce compounds that, in the long run, are not good for you — the advanced glycation end products. That happens when you have too much sugar, and it results in the complications of diabetes. They're very separate processes."

— Prof. Hudson Freeze, Director, Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute

Immunosenescence and vaccine responsiveness

The clearest illustration of glycan-driven immune change is immunosenescence, the gradual decline in immune competence that accompanies ageing. As the IgG glycome shifts with age, marked by falling galactosylation and reduced sialylation, antibodies become less able to regulate inflammation efficiently, contributing to the low-grade chronic inflammation known as inflammaging. This same shift helps explain why older adults often mount weaker antibody responses to vaccination: an immune system already skewed toward a pro-inflammatory glycosylation pattern has less capacity to mount the finely tuned response that effective vaccination depends on. Population studies suggest IgG glycosylation patterns can account for a substantial share of the variation in chronological age, which is part of why glycan profiling offers a mechanistic lens on immunosenescence, grounded in the molecular state of circulating antibodies rather than an assumption tied to age in years alone.

"We also run a set of tests for immune system function that look at lymphocyte subset panels and the accumulation of senescent T cells — the ones that don't divide anymore and secrete a lot of inflammatory markers. That's a very helpful set of markers, but it's not as linear across the age range as the glycan age is. Having this as another tool to see whether I'm improving immune system function and reducing inflammation is really great."

— Dr. Joseph Raffaele, MD, Founder, Raffaele Medical, New York City

Beyond inflammation: glycans in metabolic and neurological decline

The influence of glycosylation on ageing extends well beyond inflammation. In metabolic decline, altered N-glycosylation patterns appear years before a formal diagnosis of insulin resistance or type 2 diabetes, suggesting glycan shifts track the earliest stages of metabolic dysfunction rather than only its later consequences. In the nervous system, glycosylation governs the folding, stability and receptor interactions of proteins central to healthy brain function, and research into neurodegenerative disease has increasingly examined how disrupted glycosylation pathways relate to the protein misfolding seen in conditions such as Alzheimer's disease. In both cases, glycans act as functional effectors of disease processes rather than passive bystanders, which is part of why the field increasingly treats the glycome as a biological system worth investigating on its own terms, across multiple organ systems rather than a single disease pathway.

The future: glyco-therapeutics

Understanding glycan biomarkers of aging is increasingly feeding into treatment as well as measurement. Because many therapeutic proteins, including monoclonal antibodies, are themselves glycoproteins, their specific glycan structures determine efficacy, half-life and safety, and glyco-engineering is already used to improve drugs such as certain anti-inflammatory antibodies and long-acting erythropoietin variants. Glycan-based drugs already in clinical use include sialic acid mimetics such as antiviral neuraminidase inhibitors, while research into glycan-binding proteins and engineered glycoforms is expanding treatment options for inflammatory and autoimmune conditions. Because inter-individual differences in glycosylation are large, the same profiling used to characterise biological age is also being explored as a way to stratify which patients are likely to respond to a given glyco-therapeutic, moving the field from description toward targeted intervention.

Taken together, these mechanisms position the glycome as one of the more information-rich layers of human biology, sitting at the intersection of genetics, immune function and environmental exposure. Glycan biomarkers of aging offer a way to observe that system directly, tracking the enzymatic modifications that shape immune behaviour rather than inferring biological age from a single downstream marker, and pointing toward a future where glycan profiling informs treatment selection as much as it informs measurement.

Curious what your own glycan profile looks like? Explore the GlycanAge test and see where your immune-driven biological age stands.

External sources

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• 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):779–89. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC4049143/

• Cvetko A, Mangino M, Tijardović M, Kifer D, Falchi M, Keser T, et al. Plasma N-glycome shows continuous deterioration as the diagnosis of insulin resistance approaches. BMJ Open Diabetes Res Care. 2021;9(1):e002263. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC8438737/

• Lundstrom SL, Yang H, Lyutvinskiy Y, Rutishauser D, Herukka SK, Soininen H, et al. Blood plasma IgG Fc glycans are significantly altered in Alzheimer's disease and progressive mild cognitive impairment. J Alzheimers Dis. 2014;38(3):567–79. PMID: 24028868. Available from: https://pubmed.ncbi.nlm.nih.gov/24028868/

• Lauc G, Pezer M, Rudan I, Campbell H. Mechanisms of disease: The human N-glycome. Biochim Biophys Acta. 2016;1860(8):1574–82. PMID: 26500099. Available from: https://pubmed.ncbi.nlm.nih.gov/26500099/