Glycation is the process by which glucose molecules attach non-enzymatically to proteins in your body — including collagen and elastin in your skin — and cross-link them into rigid, structurally aged forms called advanced glycation end products (AGEs).
Monnier's foundational 1990 paper framed it precisely: this is the same Maillard reaction that browns bread crust, running slowly through your dermis when circulating glucose is chronically elevated (Monnier, 1990). The end products stiffen collagen and reduce its capacity to remodel.
Because dermal collagen turns over slowly — roughly a fifteen-year half-life (Verzijl et al., 2000) — glycation damage compounds over time. Whatever your average glucose is today shows up years later as skin that has lost elasticity, resilience, and structural quality.
How you can measure it. Skin glycation itself is measured directly through skin autofluorescence in research settings, but that technology isn't widely available at consumer scale. The best clinically-available proxy is a combination of three blood tests:
- HbA1c — your 90-day glucose average. The strongest single proxy for cumulative glycation load.
- Fasting glucose — today's snapshot.
- Fasting insulin — shifts earlier than either, when metabolism is under strain.
Together, those three markers give you a well-supported picture of your current glycation trajectory. All three are on the JenSkin panel.