A content analysis of marketing on the packages of dietary supplements for weight loss and muscle building

Most dietary supplements for weight loss and muscle growth lack scientific evidence in support of product claims and contain ingredients that can be harmful to health. Many people, however, still use these products. This paper aims to address a gap in the knowledge of the number and types of marketing claims appearing on dietary supplements for weight loss and muscle building and how they relate to the presence of an FDA disclaimer. We identified all products (n = 110) found in the weight loss and muscle building section of three stores (a pharmacy, supermarket, and superstore) in the Boston, MA area during 2013. We performed a content analysis to assess the presence of marketing claims displayed on product packaging, including claims about weight loss, safety, quality, and scientific evidence. Warnings and the FDA disclaimer were also coded. We found that, on average, products displayed 6.5 claims. Among weight loss- and muscle building- related claims, claims about reducing weight, BMI, or body fat were most common (60.9%), followed by protein claims (40.0%). Nearly half of the products made claims that scientific research supported product use. Products with the FDA disclaimer (53.6%) or a warning for vulnerable populations (56.4%) had a higher average number of claims compared to products without the disclaimer or warning (p < 0.001). Dietary supplements for weight loss and muscle building displayed many marketing claims promising weight loss despite a lack of scientific evidence that such products can be used safely and effectively. Greater FDA regulation of these marketing claims are needed.