Book excerpt: This quick-glance reference helps students and health professionals educate themselves and their patients/clients about the scientific evidence for and against more than 120 popular dietary supplements. Supplements are logically grouped into 12 chapters based on their primary desired effect, such as weight loss, joint support, and sports performance enhancement. The authors give each supplement a one-to-five-star rating based on the level of scientific substantiation for each of its major claimed effects. The book highlights crucial safety issues regarding each supplement and sets forth recommended dosages for particular effects. A quick-reference appendix lists all the supplements alphabetically with their star ratings.