Abstract: 1) Thixotropic composition comprising: from 10% to 40% by weight of a bisurea a) obtained by reaction of a primary aliphatic amine a1) with a diisocyanate a2) having a molar mass of less than 500 g/mol, and from 60% to 90% by weight of an ester b) of formula (I): in which: R1, R2 and R3 represent an oxycarbonylalkyl radical having from 4 to 20 carbon atoms; R4 represents a hydrogen atom, a methyl or ethyl radical or else a radical: —CH2—R5 in which R5 represents an oxycarbonylalkyl radical having from 4 to 20 carbon atoms; said composition being in the form of a suspension of solid particles of bisurea a) in a continuous phase formed by the ester b). 2) Adhesive sealant composition comprising at least one moisture-crosslinkable prepolymer and, as anti-sagging agent, from 5% to 30% by weight of said thixotropic composition.