Nanomaterials release quantification and characterization is crucial for risk assessment studies, and experimental simulation studies provide the most concrete basis for estimating the release of nanomaterials in any stage of its life cycle. Nanomaterials are used in a broad range of applications, in different forms (embedded, as coatings, suspended, etc.) and with different size ranges. With all these variables, the number of scenarios where release of nanomaterials could occur is huge. In this chapter, we aim to review use-phase release scenarios that are usually considered in the literature, as well as the results of such studies and the protocols used for product ageing and for nanomaterial quantification and characterization. Finally, we point out the gaps in nanomaterials release studies and identify future research needs.