ObjectiveTo understand how mothers use commercial milk formula (CMF) labels to inform their feeding choices and explore mothers’ understanding of differences between CMF products.DesignQualitative study with recruitment via social media. Online semistructured interviews, including a product mapping exercise and thematic analysis.ParticipantsMothers (n=25) using CMF for children <3 years living in Great Britain (GB).ResultsMothers were drawn to brands they recognised from years of exposure to CMF advertising. CMF products were assumed to vary according to brand and stage, but participants found on-pack information did not explain how. This added to anxiety about choosing ‘the best one’ and mothers would have liked guidance from healthcare professionals (HCPs). Wide availability of CMF for older infants and children, and on-pack messaging suggesting progression from one product to the next, led many to believe these products were necessary. There was confusion over the appropriate use of specialist products. While mothers rarely mentioned on-pack health and nutrition claims, they were attracted to the overall appearance of packs and messaging relating to science, research and nature. References to breast milk and a logo perceived to represent a breastfeeding mother were taken as indicators of closer similarity to breast milk.ConclusionsCMF legislation in GB should be updated to restrict brand advertising and the use of on-pack text and images that mothers perceive as indicating products have a closer similarity to breast milk. Greater input from HCPs was desired by new mothers and would support them to make more informed choices about CMF.