BACKGROUND: Dietary supplement (DS) use is common among U.S. Army personnel to purportedly improve health, provide energy, and increase strength. However, a comprehensive analysis of DS use among U.S. Air Force (USAF) personnel has not been conducted using the same survey instrument, which would permit direct comparisons to DS use by Army personnel.METHODS: A standardized questionnaire was used to assess DS use, demographic factors, and reasons for use of DS by USAF personnel (N = 1750). Logistic regression models adjusted for age, sex, and rank were used to determine relationships among categories of DS (multivitamin and multimineral, individual vitamins and minerals, protein/amino acid supplements, combination products, herbal supplements, purported steroid analogs, and other) and demographic factors. Findings were compared to reports from other military services and civilian populations.RESULTS: DS were used by 68% of USAF personnel: 35% used 1–2 DS ≥ 1 time/wk, 13% 3–4 DS ≥ 1 time/wk, and 20% ≥ 5 DS ≥ 1 time/wk. There were 45% of personnel who used a multivitamin and mineral, 33% protein supplements, 22% individual vitamins/minerals, 22% combination products, and 7% herbals. Logistic regression demonstrated aerobic exercise duration and strength training were associated with increased DS use. Individuals who previously deployed were more likely to use DS.CONCLUSIONS: Like Army personnel, college students and athletes, USAF personnel use more DS than the general population and are more likely to use purported performance enhancing DS, such as protein supplements, and concurrently consume multiple DS.Austin KG, Price LL, McGraw SM, Leahy G, Lieberman HR. Demographic, lifestyle factors, and reasons for use of dietary supplements by Air Force personnel. Aerosp Med Hum Perform. 2016; 87(7):628–637.