Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies was asked to provide a scientific opinion on a list of health claims pursuant to Article 13 of Regulation ( EC) No 1924/2006. This opinion addresses the scientific substantiation of health claims in relation to branched-chain amino acids and growth or maintenance of muscle mass, attenuation of the decline in muscle power following exercise at high altitude, faster recovery from muscle fatigue after exercise, improvement of cognitive function after exercise, reduction in perceived exertion during exercise and "healthy immune system". The scientific substantiation is based on the information provided by the Member States in the consolidated list of Article 13 health claims and references that EFSA has received from Member States or directly from stakeholders. The food constituent that is the subject of the health claims is branched-chain amino acids ( BCAA). The Panel considers that branched-chain amino acids is sufficiently characterised. Growth or maintenance of muscle mass The claimed effects are "reduces protein breakdown after exercise","increases protein synthesis", "recovery/increased protein synthesis in skeletal muscle during recovery from sustained strength exercise" and "muscle metabolism". The target population is assumed to be the general population. The Panel considers that growth or maintenance of muscle mass is a beneficial physiological effect. No references were provided from which conclusions could be drawn for the scientific substantiation of the claimed effect. On the basis of the data presented, the Panel concludes that a cause and effect relationship has not been established between the consumption of BCAA and growth or maintenance of muscle mass over and above the well established role of protein on the claimed effect. Attenuation of the decline in muscle power following exercise at high altitude The claimed effect is "attenuates the decline in power output following exercise at high altitude". The target population is assumed to be active individuals performing high altitude training. The Panel considers that attenuation of the decline in muscle power following exercise at high altitude is a beneficial physiological effect. No references were provided from which conclusions could be drawn for the scientific substantiation of the claimed effect. On the basis of the data presented, the Panel concludes that a cause and effect relationship has not been established between the consumption of BCAA and attenuation of the decline in muscle power following exercise at high altitude. Faster recovery from muscle fatigue after exercise The claimed effects are "muscle metabolism" and " promotes muscle recovery after exercise". The target population is assumed to be active individuals in the general population. In the context of the proposed wordings and clarifications provided by Member States, the Panel assumes that the claimed effect refers to recovery from muscle fatigue after the performance of physical exercise. The Panel considers that faster recovery from muscle fatigue after exercise is a beneficial physiological effect. No references were provided from which conclusions could be drawn for the scientific substantiation of the claimed effect. On the basis of the data presented, the Panel concludes that a cause and effect relationship has not been established between the consumption of BCAA and faster recovery from muscle fatigue after exercise. Improvement of cognitive function after exercise The claimed effect is " improves mental performance after exercise". The target population is assumed to be the general population. In the context of the clarifications provided by Member States, the Panel assumes that the claimed effect relates to improving cognitive function after exercise. The Panel considers that improvement of cognitive function after exercise is a beneficial physiological effect. In weighing the evidence, the Panel noted that only one study using a small number of volunteers showed a significant effect of BCAA consumption compared to a non-isocaloric placebo on one of the cognitive endpoints measured and that two studies which compared the effect of BCAA-containing drinks to non-isocaloric placebo drinks did not show any significant effect of BCAA on the cognitive endpoints measured. On the basis of the data presented, the Panel concludes that a cause and effect relationship has not been established between the consumption of BCAA and improvement of cognitive function after exercise. Reduction in perceived exertion during exercise The claimed effect is "BCAAs improve performance during sustained exercise". The target population is assumed to be active individuals in the general population. In the context of the proposed wordings and clarifications provided by Member States, the Panel assumes that the claimed effect refers to a reduction in perceived exertion during exercise. The Panel considers that a reduction in perceived exertion during exercise is a beneficial physiological effect. The Panel notes that in the only human study provided which addressed the effect of BCAA consumption on perceived exertion during exercise the number of subjects recruited was small, and that the study was not adequately controlled for energy intake ( i.e. energy content of the BCAA drink was higher than that of placebo), which could have accounted for the differences in RPE observed between groups, all of which greatly limit the conclusions that can be drawn from this study for the scientific substantiation of the claimed effect. On the basis of the data presented, the Panel concludes that a cause and effect relationship has not been established between the consumption of BCAA and a reduction in perceived exertion during exercise. "Healthy immune system" The claimed effect is "help maintain a healthy immune system". The target population is assumed to be the general population. The claimed effect is not sufficiently defined and no further details were provided in the proposed wordings. The clarifications provided by Member States refer to the "improvement of some plasma markers of immune response" and the references provided report on changes in a number of biochemical variables related to the immune system following the administration of BCAA. However, the Panel considers that the evidence provided does not establish that changes in these immune parameters are per se a beneficial physiological effect. On the basis of the data presented, the Panel concludes that a cause and effect relationship has not been established between the consumption of BCAA and a beneficial physiological effect related to a "healthy immune system".