Galectin-3

Galectin-3 is a protein released by immune cells during inflammation and scarring (fibrosis) in the body. Higher levels in the blood can suggest that the heart, liver, kidneys, or other organs may be undergoing increased scarring or stress, and it is most commonly used to help assess the outlook for people with heart failure. A single result should always be discussed with a healthcare provider, as many factors—including kidney function—can affect the level.

When elevated: Elevated galectin-3 levels are associated with increased myocardial fibrosis, worse prognosis in heart failure (both HFrEF and HFpEF), higher risk of cardiovascular events, and progression of hepatic, renal, or pulmonary fibrosis. Persistently high levels may indicate ongoing macrophage activation and pathological tissue remodeling. When low: Low galectin-3 levels are generally considered favorable and are associated with less fibrotic burden and lower risk of adverse cardiovascular outcomes. However, low levels do not exclude underlying disease and must be interpreted alongside clinical context.

Galectin-3 is not a primary sports performance biomarker. However, it may be relevant for endurance athletes or those undertaking intense training programs, since extreme exertion can trigger systemic inflammation and tissue remodeling. Elevated levels might signal excessive training stress, inadequate recovery, or early cardiac adaptations—warranting assessment alongside standard cardiac markers if chronically elevated.