N-Acetyl Glucosamine (NAG) is a naturally occurring amino sugar and a derivative of glucose, commonly found as a component of glycosaminoglycans, which are essential for the structural integrity of many tissues, including mucus membranes. Scientific interest in NAG for supporting mucus membranes, particularly in the gastrointestinal tract, is based on its role as a building block in the synthesis of mucin, the principal component of mucus. Mucins help to protect and lubricate the lining of the gut and other mucosal surfaces.

Several in vitro and animal studies have demonstrated that NAG can enhance the production of mucin and support the repair of the epithelial barrier. For example, research has suggested that NAG supplementation may help restore the protective mucus layer in models of colitis and inflammatory bowel disease (IBD). Some small-scale human studies and case reports have explored the use of NAG in patients with IBD, with indications of symptomatic improvement, but robust clinical trials are lacking.

Overall, the scientific evidence is moderate: there is a plausible mechanism, supportive preclinical data, and limited clinical evidence, but more large, high-quality studies are needed to definitively establish benefits for mucus membrane health in humans.