R Dor is an oxygen-rich AGB star characterised by a low mass-loss rate. Using retrieval methods, we found abundance profiles for SiO and HCN, two chemically important molecules. By comparing these results to those of forward chemistry modelling we will be able to constrain the dominant chemical pathways within the stellar wind. They will also enable us to improve the forward chemistry models, through incorporating dust-gas reactions. The same methodologies will be applied to the abundance profiles retrieved for the O-rich AGB star IK Tau (Decin et al. 2010), which is characterised by a high mass-loss rate.