Background <p>Lactate, traditionally viewed as a biomarker of hypoxia and severity in critical illness, has recently emerged as a potential therapeutic agent. Its roles extend beyond energy metabolism to include anti-inflammatory and signaling functions. This review explores the evolving evidence supporting lactates therapeutic application in critical care settings.</p> Main body <p>We synthesize current knowledge on lactate physiology, including its production, transport, and metabolism across organs. Experimental models and clinical studies data suggest that exogenous lactate, particularly in the form of hypertonic sodium lactate (HSL), improves hemodynamics, reduces inflammation, and enhances organ function in sepsis, acute heart failure, and brain injury. Lactate administration shows promise in restoring metabolic homeostasis, improving microcirculation, and supporting cardiac and cerebral recovery. However, clinical studies in critical care remain limited, largely because lactate is predominantly regarded as a marker of poor prognosis rather than as a potential energy substrate with therapeutic value.</p> Conclusion <p>Lactate-based therapy represents a paradigm shift in the management of critical illness. While preclinical data are promising, larger, well-designed randomized trials are needed to establish its safety, efficacy, and optimal indications. The therapeutic repositioning of lactate could complement or replace current resuscitation fluids and metabolic modulators in intensive care unit (ICU).</p> Graphical Abstract <p></p>