F2 Isoprostanes or F4 neuroprostanes (brain) measured in tissue or urine (for systemic ox stress) by GC-mass spec. There are several pitfalls associated with TBARS/MDA, (lack of sensitivity and specificity). Protein adducts resulting from lipid peroxidation such as 4-hydroxynonenal can be assessed by western blot but once again, not so sensitive.