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 5-hydroxytryptophan and increase in satiety leading to a reduction in energy intake. 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 claim is 5-hydroxytryptophan (5-HTP). The Panel considers that 5-hydroxytryptophan is sufficiently characterised. The claimed effect is “satiety”. The target population is assumed to be the general population. The Panel considers that an increase in satiety leading to a reduction in energy intake, if sustained, might be a beneficial physiological effect. No references were provided from which conclusions could be drawn for the scientific substantiation of the claim. On the basis of the data presented, the Panel concludes that a cause and effect relationship has not been established between the consumption of 5-hydroxytryptophan and a sustained increase in satiety leading to a reduction in energy intake.