3'-fucosyllactose

**3'-Fucosyllactose (3'-FL)** is a trisaccharide human milk oligosaccharide (HMO) naturally abundant in breast milk, second only to 2'-fucosyllactose after early lactation, consisting of lactose with an α1-3 linked fucose on the glucose residue. It functions primarily as a prebiotic, selectively promoting growth of beneficial gut bacteria like *Bifidobacteria* and *Lactobacillus*, leading to increased production of short-chain fatty acids (SCFAs) that strengthen intestinal barrier integrity, regulate metabolism, and exert anti-inflammatory effects by reducing pro-inflammatory cytokines such as IL-6 and TNF-α. Additional benefits include immunomodulation via cell signaling and microbial adhesion inhibition, antimicrobial activity against pathogens like *E. coli* and *P. aeruginosa*, support for brain development through sialic acid provision and gut-brain axis regulation, and antiviral protection; it is produced via microbial fermentation for use in infant formulas, foods, and supplements, with regulatory approvals confirming safety up to levels mimicking breast milk exposure.

Other names

3-FL3-fucosyllactose