FGF21 (Fibroblast Growth Factor 21)

Fibroblast Growth Factor 21 (FGF21) is an emerging metabolic biomarker that plays a central role in regulating energy balance, glucose metabolism, lipid metabolism, and insulin sensitivity. Produced primarily by the liver, FGF21 acts as a signalling protein that helps the body respond to periods of metabolic stress and adapt to changes in nutrient availability.

As growing rates of obesity, type 2 diabetes, and metabolic dysfunction-associated fatty liver disease (MAFLD/MASLD) continue to place a significant burden on healthcare systems worldwide, FGF21 has attracted increasing attention as a valuable indicator of metabolic health and disease risk. Elevated circulating levels of FGF21 have been associated with a range of cardiometabolic conditions, making it a promising biomarker for risk stratification, disease monitoring, and preventative healthcare.

Clinical Significance of FGF21

Obesity and Metabolic Syndrome

FGF21 is believed to exert protective effects against metabolic dysfunction by improving insulin sensitivity and promoting healthy energy metabolism. However, individuals with obesity often display elevated FGF21 concentrations, which may represent a compensatory response to increased metabolic stress. Higher FGF21 levels have been linked to key features of metabolic syndrome, including:

• Central obesity
• Insulin resistance
• Hypertension
• Dyslipidaemia

Research suggests that FGF21 concentrations rise progressively with the number of metabolic syndrome components present, potentially offering clinicians a valuable tool for identifying individuals at increased risk of future metabolic disease.

Fatty Liver Disease (NAFLD/MASLD)

Non-alcoholic fatty liver disease, now increasingly referred to as metabolic dysfunction-associated steatotic liver disease (MASLD), is closely associated with obesity and insulin resistance. FGF21 has demonstrated potential as a non-invasive biomarker for liver fat accumulation and disease progression.

Studies have shown that:

• Individuals with fatty liver disease typically exhibit higher circulating FGF21 levels.
• FGF21 concentrations increase as liver disease severity progresses.
• Changes in FGF21 levels correlate with changes in hepatic fat content.