The effectiveness of popular, non-prescription weight loss supplements

Objectives: To review the evidence for the effectiveness of popular, non-prescription weight loss supplements. Data sources: A detailed literature search including all relevant medical and supplementary medicine databases and evidence submitted from manufacturers. Data synthesis: The theoretical basis and rationale for the use of each substance is considered along with available research in the published literature on effectiveness and potential risks. We classified the level of evidence represented by the main research studies on each substance. Conclusions: There is no good evidence for any weight loss benefits from most of the substances reviewed here. There is some support for mild effects of capsaicin, caffeine and fibre, but only in whole foods. In some cases leg, chitosan), there is a plausible theoretical basis for the product, but no supporting proof of effect in humans in the absence of a calorie-controlled diet. Possible synergistic effects of different ingredients cannot be dismissed, but cannot be assessed from current data. There is an absence of good quality research on many substances, which means that advertising claims may be misleading.