Dietary supplements are widely available through a rapidly expanding market of products commonly advertised as beneficial for health, performance enhancement, and disease prevention. Given the importance and frequent evaluation of physical performance and health as a criteria to join and remain in the military, the use of these products by military personnel has raised concern regarding over-all and long-term efficacy and safety. This evaluation is especially difficult, as many of these supplements contain multiple ingredients, have a changing composition over time, or are used intermittently at doses difficult to measure. This book analyzes the patterns of dietary supplement use among military personnel, examines published reviews of the scientific evidence, and identifies those dietary supplements that are beneficial and/or warrant concern due to risks to health or performance. The book also recommends a system to monitor adverse health effects and a framework to identify the need for active management of dietary supplements by military personnel. Military policy makers, personnel, and recruits will find this book useful, as will nutritionists, athletes, and others working in strenuous environments.