Having established that [mono-alcohol + polyol] mixtures are suitable to obtain surfactant-free Au NPs, see Figure , we further explore the effects of using mixtures of ethanol and glycerol, with a focus on low glycerol contents. The hypothesis is that the formation of the Au NPs is sensitive to the conditions under which the very initial steps of the synthesis take place. This hypothesis is motivated by the findings from our previous study focusing on different light environment, where a hybrid approach of light controlled environment and dark conditions show that the light conditions had a strong influence mainly at the beginning of the synthesis. In other words, the use of lights with low wavelengths to obtain small size NPs was mainly key in the first minutes of the reaction. It is here hypothesized that small amount of glycerol might help to achieve size control towards smaller NPs by playing a role in the initial steps of the synthesis by favoring a faster formation of the NPs.