Scientific Opinion on the substantiation of health claims related to L-glutamine and growth or maintenance of muscle mass (ID 719, 722, 3185), faster restoration of muscle glycogen stores after strenuous exercise (ID 434, 699, 701, 723, 1569), skeletal muscle tissue repair (ID 721), maintenance of normal neurological function (ID 662, 700), increased attention (ID 700, 1570), improvement of working memory (ID 700, 1570), maintenance of defence against pathogenic gastro-intestinal microorganisms (ID 452), gut protein synthesis (ID 701), decreasing gut permeability (ID 701), and stimulating immunological responses (ID 1568) pursuant to Article 13(1) of Regulation (EC) No 1924/2006