A team of 7 SIPA students supported Natura Cosmetics in developing and testing a social impact assessment methodology to understand Natura’s “first mile” impact on Amazon rainforest communities who supply natural resources to Natura. After an initial field visit to Brazil and a desk research phase, the SIPA team designed three data-gathering tools: (1) household survey, (2) focus group guide, (3) semi-structured interview guides. In collaboration with Natura and colleagues from the University of São Paulo, the SIPA team piloted the tools in the community of Cametá, one of 37 communities across Brazil where Natura works. The findings from our fieldwork informed the further refinement of the methodology and offered initial insights into Natura’s social impact on its supplier communities. Through this engagement, the SIPA team has offered Natura a starting point for building a robust impact assessment methodology to be scaled across its full supplier community.