Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods andFood Allergens (NDA) was asked to deliver an opinion on the relationship between alpha-lipoic acid(ALA) and the risk of insulin autoimmune syndrome (IAS). The Panel was also asked to advise on thedose below which ALA added to foods is not expected to cause IAS. A review of all possible adverseeffects associated with consumption of ALA was not requested. This mandate refers to the procedureunder Article 8(2) of Regulation (EC) No 1925/2006 on addition of vitamins, minerals and certain othersubstances to foods. No pre-established rule exists for the evaluation of the safety of foods whenclassical toxicity tests cannot be used, e.g. for autoimmune diseases. Published scientific evidence wasretrieved through comprehensive literature searches, particularly 49 case reports in which IASdeveloped following ALA consumption. In all cases, IAS resolved after a few weeks to months whenALA was discontinued. No publication linking the intake of ALA naturally occurring in foods to IAS wasidentified. The Panel concludes that the consumption of ALA added to foods, including foodsupplements, is likely to increase the risk of developing IAS in individuals with certain geneticpolymorphisms, who cannot be readily identified without genetic testing. The plausible mechanism ofsuch an effect has not yet been fully elucidated. The incidence of IAS in Europe is low and likely lowerthan in Japan where it has been estimated to be 0.017 per 100,000 inhabitants in 2017–2018.Considering the limited data available, the risk associated with the development of IAS following ALAconsumption cannot be quantified precisely. An ALA dose below which IAS is not expected to occur islikely to vary between individuals and cannot be determined from the available data