FFAs

FFAs is an acronym with several possible meanings, but it is most commonly encountered in biochemistry to denote free fatty acids. Free fatty acids are fatty acids that are not esterified to glycerol; in the body they are released from adipose tissue during lipolysis and circulate in the blood largely bound to albumin, providing an important energy source for tissues such as muscle and liver.

In terms of structure, FFAs can be classified by chain length and degree of saturation. The majority are long-chain fatty acids, and they can be saturated or unsaturated. Short- and medium-chain fatty acids also occur but are less abundant in circulating pools. Metabolically, FFAs are transported into cells and, in the mitochondria, undergo beta-oxidation to generate acetyl-CoA and ATP. They also function as signaling molecules, acting on nuclear receptors such as PPARs and influencing pathways related to glucose and lipid metabolism.

Physiologically, FFAs are a key energy substrate during fasting or exercise. Hormonal signals regulate their release from adipose tissue; insulin generally suppresses lipolysis, lowering FFA availability. Clinically, chronically elevated plasma FFAs have been associated with insulin resistance, type 2 diabetes, and hepatic steatosis, while abnormal FFA handling is a feature of several metabolic disorders. Measurements of FFAs are used in metabolic research and some clinical assessments, with careful sample handling required to avoid ex vivo lipolysis.

Outside biochemistry, FFAs can refer to other, non-scientific uses of the acronym in different contexts; in science writing, the primary meaning remains free fatty acids.