Background and aims: The link between hyperglycemia and endogenous glycation has long been established. There are several hypotheses regarding the mechanisms inducing endogenous glycation. Using the nematode Caenorhabditis elegans, Schlotterer et al. have shown that methylglyoxal (MGO) produced during glycolysis induces the production of MGO-derived hydroimidazolone (MG-H1). This AGE induces mitochondrial dysfunction and reduces the worms’ longevity (Diabetes. 2009. doi: 10.2337/db09-0567). More recently, our preliminary work showed that N-carboxymethyl-lysine (CML) is also produced when C. elegans is grown in a glucose-rich medium, suggesting that a mechanism independent of MGO production is involved. To highlight this mechanism, we first analysed the impact of different environmental factors (dietary nutrients and microbiota) on the induction of endogenous CML by glucose. Materials and methods: Worms were incubated with different concentrations of glucose in 2 different media: a medium containing peptone and a defined medium without peptone. Worms were grown in the presence of live or inactivated bacteria. Lifespan assays were performed. The relative amount of CML in the worms was quantified by dot-blot. Immunohistochemical analyzes were used to detect CML epitopes in the worms. Different oxidation markers were measured: expression of antioxidant genes by RT-qPCR and oxidation of proteins by oxyblot. The expression of genes encoding glyoxalases and scavenger receptors were measured by RT-qPCR. Results: The longevity of the worms was reduced by the glucose diets in a dose-dependent manner. The pathophysiological effect of glucose was greater with live bacteria and in the medium without peptone. CML epitopes were detected in the apical part of the intestine of worms grown with glucose. The amount of CML epitopes depended on glucose concentration and was highest in worms incubated with inactive bacteria in medium without peptone. The expression of genes encoding antioxidant proteins, including superoxide dismutase SOD-3 and glutathione-S-transferase GST-4, depended on on glucose concentration. These genes are more expressed when worms were grown with live bacteria in the medium without peptone. Expression of the gene encoding the glutathione-independent glyoxylase, DJR-1.2, was induced by glucose in a dose-dependent manner. This gene was more expressed when worms were grown with inactivated bacteria. Some genes encoding scavenger receptors wee more expressed by worms grown in the medium with glucose and peptone. Conclusion: An association between glucose-rich diet, oxidative markers, endogenous glycation and worms’ longevity has been demonstrated in C. elegans under certain culture conditions, especially in media with inactive bacteria. These results show that different factors modulate the pathophysiology of glucose. To study the physiopathological mechanisms of glucose linked to endogenous glycation, it is essential to grow C. elegans in a medium with inactive bacteria and preferably without peptone.