ImportanceDietary supplements for weight loss, among the most popular supplement products on the market, are promoted not only for losing weight and shedding fat, but also for added benefits of energy and performance, all packed into 1 capsule with multiple combinations of ingredients. Fraudulent marketing of weight loss supplements, some with exaggerated claims, some that are potentially dangerous, and some that contain illegal ingredients, is ever present, especially through online sources, where multiple manufacturers target service members by offering military discounts.ObjectivesTo examine whether select dietary supplements marketed online for weight loss from companies advertising military discounts are accurately labeled according to the Supplement Facts listed ingredients, whether they contain any ingredients prohibited for use in the military, and to qualitatively describe the products’ label claims.Design, Setting, and ParticipantsIn this case series, 30 dietary supplement products marketed for weight loss were selected and purchased in June 2023 from 12 online companies advertising military discounts. Data were analyzed from July to August 2023.Main Outcomes and MeasuresLiquid chromatography-mass spectrometry was used to verify whether products were accurately labeled according to the Supplement Facts listed ingredients and whether they contained any substances on the DoD Prohibited Dietary Supplement Ingredients List. A separate analysis was conducted to describe product label claims by using the Operation Supplement Safety (OPSS) Risk Assessment Scorecard.ResultsOf the 30 products tested, analysis showed that 25 had inaccurate labels. Of these, 24 had ingredients listed on the label that were not detected (misbranded); 7 had hidden components not present on the label, some of which would be considered adulterated; and 10 had substances on the DoD Prohibited Dietary Supplement Ingredients List either on or hidden from the label. All products were rated as risky when applying the OPSS Scorecard.Conclusions and RelevanceIn this case series study, the majority of products had inaccurate labels. Some were misbranded, others would be considered adulterated with ingredients not allowed in dietary supplements, and some contained ingredients prohibited for use in the military.