Lactate is transported via the lactate shuttle and oxidized in mitochondria to support energy production in cardiac and neural tissues.

Study: Natural killer loops: pyruvate in, lactate out

This study shows that cells can turn pyruvate into lactate and then use that lactate to help make energy in their power plants (mitochondria), which supports the idea that lactate isn't just waste—it's a fuel.

Study: Aerobic Production and Utilization of Lactate Satisfy Increased Energy Demands Upon Neuronal Activation in Hippocampal Slices and Provide Neuroprotection Against Oxidative Stress

The study shows that brain cells use lactate as fuel by bringing it inside and burning it in their energy factories (mitochondria) to stay alive during stress—just like the claim says. Lactate worked better than other substances and only worked when a specific enzyme (mLDH) was present, proving it’s being used for energy.

Study: NH4+ triggers the release of astrocytic lactate via mitochondrial pyruvate shunting

The study shows that brain cells (astrocytes) make and send out lactate when they're active, which means lactate is available for other brain cells to use as fuel — supporting the idea that lactate is a mobile energy source in the brain.

Study: Intracellular Shuttle: The Lactate Aerobic Metabolism

The study shows that lactate, often thought of as just a waste product, can actually be carried into heart and brain cells and burned in their energy factories (mitochondria) to make power. This supports the idea that lactate is a useful fuel, not just a byproduct.