The Panel on Food Additives and Nutrient Sources added to Food provides a scientific opinion on the use ofmonomethylsilanetriol added for nutritional purposes to food supplements. The Panel was asked to evaluate towhich extent newly submitted information addresses the uncertainties expressed in its opinion on“Monomethylsilanetriol added for nutritional purposes to food supplements” in 2009. The Panel noted that thenewly submitted information relates to the bioavailability of silicon from, and to the toxicology of a sourcesubstance designated as monomethylsilanetriol orthohydroxybenzoate sodium salt (MSS). This substance differsfrom the substances evaluated by the Panel in 2009 since, unlike the substances evaluated previously, thecommercial form of MSS consists of an aqueous solution of salicylic acid (orthohydroxybenzoic acid), monomethylsilanetriol and sodium chloride. In the light of the newly submitted information and given the factthat the presence of salicylic acid in MSS may influence the bioavailability of silicon from MSS, and the toxicityof MSS, the Panel concluded that the new data are insufficient to fill the data gaps on the bioavailability ofsilicon from monomethylsilanetriol and on the toxicity of monomethylsilanetriol, which were highlighted in theopinion of 2009. The Panel therefore concludes, that the newly submitted information does not adequatelyaddress the uncertainties expressed in the previous opinion and would not justify the re-evaluation ofmonomethylsilanetriol added for nutritional purposes in food supplements.