Nanolime products are one of the most promising consolidation methods for historic calcareous substrates. Whilst the popularity of nanolime has been growing, its consolidation mechanism still needs to be fully understood when applied to highly porous substrates. The aim of this paper is to compare the three available nanolime products in terms of consolidation efficacy on lime mortar specimens. It is shown that repeated applications of a low concentrated nanolime can increase the superficial cohesion and the mechanical strength of the mortar within 1?cm from the surface, while also reducing porosity, number of micro-pores and capillary water absorption coefficient. Nanorestore Plus® yielded the highest short-term consolidation effect. However, LAquila nanolime showed a higher durability which was attributed to a better developed crystalline structure.