Iron supplementation programs, despite evidence of their effectiveness in controlled conditions, are not effective as largescale interventions in health services because of the necessary involvement during execution of a series of processes that, when not fulfilled, limit the implementation of the program. In many cases, the lack of impact of interventions to provide iron supplements is the result of failures or deviations from execution rather than flaws in the intervention design (theory of change) or intervention strategy. The objective of this study was to share the lessons learned in the execution of a community trial in 2015 to improve adherence to micronutrient powder supplementation in children younger than 3 years in four regions of Peru, as well as to provide recommendations on iron supplementation in children to help close gaps in the design and execution of public policies.