Notably, glioma cells exhibited significantly higher concentrations of intracellular GSH (IDH1‐WT GL261: 10.17 ± 1.45 mm, IDH1‐MUT GL261: 8.56 ± 0.67 mm) compared to normal brain cells (astrocytes: 1.78 ± 0.33 mm, neurons: 2.21 ± 1.05 mm, macrophages: 1.28 ± 0.40 mm) as measured by the I542/I928 ratio (Figure 4B,D; Figure S10, Supporting Information). Here, IDH1 is linked to glioma.