The culture of mesenchymal stromal cells relies on the use of suspended microcarriers as adhesion supports. During the particle suspension phases, the temporal evolution of the spatial distribution of particle concentrations is generally poorly characterized. In this study, the light attenuation technique was used to access this distribution and the duration of particle homogenization. Considering the minimal agitation rate Nref for which particle suspension was observed for all the microcarrier concentrations 〈C〉 studied, the results showed that using an agitation frequency close to Nref significantly increased the homogenization duration compared to N≃1.7×Nref. The transient microcarrier overconcentration was also determined locally. At N=Nref, the resuspension time was negatively impacted by 〈C〉, which also resulted in longer particle overconcentrations. A time-integral particle overconcentration term was considered to estimate the severity of inter-microcarrier collisions. The results suggested that increased agitation could limit time-cumulative overconcentrations beyond a particle concentration of 3 g/L.