Ferroptosis is a form of regulated cell death triggered by the loss of glutathione peroxidase 4 (GPX4) activity, leading to the accumulation of lipid hydroperoxides. This study identifies that phosphatidylethanolamines (PEs) containing arachidonoyl (AA) and adrenoyl (AdA) fatty acids are oxidized in the endoplasmic reticulum (ER) to generate ferroptotic signals. Oxidized AA and AdA-PEs are produced by lipoxygenases (LOX), which catalyze the oxidation of these fatty acids. The study shows that the oxidation of AA and AdA into PE is facilitated by acyl-CoA synthase 4 (ACSL4), and that inhibiting ACSL4 reduces ferroptosis. Vitamin E derivatives, such as tocopherols and tocotrienols, suppress LOX activity and protect against ferroptosis, suggesting a physiological role for vitamin E in maintaining redox balance. The study also demonstrates that the oxidation of AA and AdA-PEs is a key pathway for ferroptotic signaling, and that this process is regulated by a highly organized oxygenation center in the ER. The findings highlight the importance of lipid peroxidation in ferroptosis and suggest that targeting this pathway could be a potential therapeutic strategy for diseases associated with ferroptosis.Ferroptosis is a form of regulated cell death triggered by the loss of glutathione peroxidase 4 (GPX4) activity, leading to the accumulation of lipid hydroperoxides. This study identifies that phosphatidylethanolamines (PEs) containing arachidonoyl (AA) and adrenoyl (AdA) fatty acids are oxidized in the endoplasmic reticulum (ER) to generate ferroptotic signals. Oxidized AA and AdA-PEs are produced by lipoxygenases (LOX), which catalyze the oxidation of these fatty acids. The study shows that the oxidation of AA and AdA into PE is facilitated by acyl-CoA synthase 4 (ACSL4), and that inhibiting ACSL4 reduces ferroptosis. Vitamin E derivatives, such as tocopherols and tocotrienols, suppress LOX activity and protect against ferroptosis, suggesting a physiological role for vitamin E in maintaining redox balance. The study also demonstrates that the oxidation of AA and AdA-PEs is a key pathway for ferroptotic signaling, and that this process is regulated by a highly organized oxygenation center in the ER. The findings highlight the importance of lipid peroxidation in ferroptosis and suggest that targeting this pathway could be a potential therapeutic strategy for diseases associated with ferroptosis.