Chromatographic Identification of Adulterants in Herbal Weight Loss Products Sold in Gyms in Lagos State

The market for herbal weight loss and slimming products has expanded rapidly in Lagos State, driven by increasing obesity prevalence and widespread promotion through social media channels. Regulatory investigations globally have repeatedly identified the presence of undeclared prescription drugs such as sibutramine, orlistat, and phenolphthalein in such products. This study used Thin Layer Chromatography and High-Performance Liquid Chromatography to screen fifteen herbal weight loss products purchased from gymnasia and fitness centres across Lagos Island and Surulere for undeclared pharmaceutical adulterants. Reference standards for sibutramine hydrochloride, fluoxetine, phenolphthalein, and caffeine were used for comparative chromatographic identification. HPLC quantification was performed for confirmed detections. TLC profiling indicated the presence of undeclared compounds in nine of the fifteen products. HPLC confirmed sibutramine in four products at concentrations ranging from 8 to 22 mg per dose unit, phenolphthalein in three products, and excess caffeine in six products. Sibutramine, withdrawn from global markets due to cardiovascular risks, poses a serious public health risk when present in unregulated products. These findings call for urgent regulatory action against the sale of adulterated herbal slimming products at fitness facilities in Lagos State and the enforcement of penalties for distribution of products containing banned pharmaceutical substances. Keywords: herbal slimming products, sibutramine, HPLC, adulteration, Lagos State.