Summary: Dietary supplements are increasingly used by persons with prediabetes and type 2 diabetes. These products, which are taken by the patients with the intention of improving their health, hardly ever find their way to the professional medical guidelines, although they are widely available and prescription-free. And as often as they are used by the patients, equally often they are disregarded and held in contempt by their physicians. Available evidence regarding 10 most popular dietary supplements used to decrease insulin resistance and lower blood glucose is summarized in the article, and the evidence-based conclusions regarding the use of each of them are made.