A small pilot study at UCLA has found that breast cancer survivors who took a nutritional supplement called oxaloacetate for eight weeks reported sharply improved cognitive function — a preliminary but closely watched result for patients living with so-called "chemo brain."
The phase II trial enrolled 18 women with early-stage breast cancer, one to five years past diagnosis, who reported ongoing trouble with memory, focus or mental clarity after treatment. All 18 received 500 milligrams of oxaloacetate twice a day; there was no placebo group and no comparison arm, a limitation the researchers themselves flagged. Sixteen participants completed the full eight weeks.
On the trial's main measure of perceived cognitive impairment, scores rose from an average of 29.1 before treatment to 55.5 afterward — a jump researchers described as substantial given the group's small size. Neuropsychological testing also picked up improvements in executive function and processing speed, which the study's authors called preliminary findings that will need confirmation. The results were published in JCO Oncology Advances, and oxaloacetate was reported to be generally well tolerated.
Why researchers are cautious
"Chemo brain" — the fog, forgetfulness and slowed thinking many cancer survivors report during and after treatment — is common but still poorly understood, and has no approved drug treatment. Oxaloacetate is a naturally occurring molecule involved in cellular energy metabolism; researchers have theorized, but not proven, that supplementing it might help cells in the brain recover from the metabolic stress of chemotherapy.
Because every participant in this trial knew they were taking the supplement and there was no comparison group, the UCLA Health team behind the study was careful to describe the results as a signal worth testing further, not evidence the supplement works. Self-reported improvement, in particular, can reflect expectation as much as any underlying biological change.
The researchers are now preparing a randomized, placebo-controlled follow-up trial, registered on ClinicalTrials.gov, expected to open to new participants in late 2026. Until those results are in, the team's advice to survivors curious about the supplement is unchanged: talk to your own oncologist before adding it, since oxaloacetate's interactions with other cancer treatments haven't been studied at scale.
