Core Viewpoint - WonderLab, a leading brand in the probiotic sector, has achieved significant sales during the "Double 11" shopping festival, but faces controversy regarding the effectiveness of its products, particularly in weight loss claims [1][7][11]. Sales Performance - As of November 11, 2025, WonderLab's "B420+S100" probiotic combination was the top seller on Taobao, with over 50,000 units sold at a post-coupon price of 477.26 yuan per set [1][4]. - The pricing of WonderLab's products is relatively high compared to competitors, with the B420 probiotic priced at 7.48 yuan per bottle, while similar products from other brands are cheaper [6][4]. Consumer Complaints - There are 117 complaints related to WonderLab on the Black Cat Complaints platform, primarily concerning ineffective weight loss and side effects [1][7]. - A consumer reported spending over 1,000 yuan on the B420+S100 combination without any weight loss, suggesting the product may not deliver on its promises [7]. Scientific Backing and Claims - Medical professionals assert that probiotics are primarily used for diarrhea and gut function disorders, not for weight loss, indicating that marketing claims linking probiotics to weight loss are exaggerated [8][9]. - Clinical studies cited by WonderLab show limited weight loss effects, with improvements in gut function rather than direct weight loss [7][9]. Marketing Practices - WonderLab's marketing strategies include using phrases that imply weight loss benefits, despite disclaimers stating that the products are ordinary foods without therapeutic claims [11][13]. - The brand has been criticized for misleading advertising, as promotional materials suggest weight loss effects while the product details clarify that it does not guarantee such outcomes [13][11]. Company Background - WonderLab was established in 2019 and has rapidly grown, achieving over 600 million bottles sold by March 2025, becoming the top seller in China's probiotic market [14]. - The company has undergone multiple rounds of financing, attracting investments from notable firms like IDG Capital and Temasek [14]. Regulatory Issues - A subsidiary of WonderLab faced penalties for producing non-compliant products, raising concerns about quality control in its manufacturing processes [15][17]. - The company has not responded to inquiries regarding the compliance and effectiveness of its B420 probiotic products [21].