Objective: Nutritional supplements are inadequately regulated in South Africa. These types of products are increasingly advertised and the advertisements frequently contain health claims. Because advertisements play a considerable role in informing potential consumers, it is crucial that information about supplements in advertisements is accurate. A survey was carried out to determine the extent to which health claims are made in nutritional supplement advertisements and to describe the appropriateness of the research cited within the advertisements in support of the health claims.Design: The design was a descriptive survey.Method: The five women’s magazines with the highest circulation figures in South Africa in July 2010 were identified by the Audit Bureau of Circulations of South Africa as Cosmopolitan, Finesse, Move!, Rooi Rose and Sarie. Issues of these magazines were obtained during the period from September 2010 to August 2011. Pre-specified eligibility criteria were used to identify suitable advertisements and to determine the percentage of nutritional supplements about which health claims were made. The percentage of these supplements for which research was cited in support of the claims was also determined, and the level and appropriateness of the cited research, described.Results: In total, 486 eligible advertisements were identified which referred to 158 nutritional supplements. Of these, 137 (86.7%) made health claims and 9 of the 137 (6.6%) cited research to support their claims. The cited research was judged to be largely inappropriate based on study design and/or the characteristics of the study.Conclusion: South Africans should be wary of advertisements that make claims about the health benefits and safety of nutritional supplements. Regulation of the advertising of nutritional supplements is urgently needed.Keywords: dietary supplements, health claims, regulation, advertising, evidence based health car