ABSTRACT
Background:
Caffeine reaches medical students through coffee, tea, soft drinks, tablets and energy drinks, but these products differ in composition and exposure. Reported prevalence varies because studies use different definitions, recall periods and samples.
Objective:
To synthesize evidence on caffeine and energy drink use among medical students, distinguish product-specific from total-caffeine exposure, examine associated factors and outcomes, and appraise evidence quality.
Methods:
This structured narrative review searched PubMed, Scopus and Web of Science, supplemented by Google Scholar and citation searching, for peer-reviewed English-language empirical studies published from 1 January 2000 to 30 June 2026. The final search was run on 30 June 2026; the full search strategies and the study selection flow are reported in the main text. SANRA and applicable PRISMA 2020 reporting items guided conduct. Cross-sectional studies were appraised using the eight-domain Joanna Briggs Institute checklist. Heterogeneous exposure definitions and recall periods precluded pooling.
Results:
Fourteen studies involving 5,815 participants met the criteria: 13 cross-sectional surveys and one repeated cross-sectional mixed-methods study. Energy drink estimates ranged from 41.4% past-six-month use in Kazakhstan and 50.0% ever use in Jordan to 62.0% current use in India, 63.9% reported use in Pakistan and 75.8% use among Polish medical students. Total-caffeine studies reported 93.6% use in South Africa and 81.3% in Saudi Arabia; 52% of Saudi users consumed at least 400 mg/day. Students commonly cited wakefulness, concentration and fatigue management, particularly during examinations. Sleep was the most consistent health-related domain. No study demonstrated academic benefit. Recurrent limitations included convenience sampling, self-reported intake, limited confounder control and absent temporal ordering.
Conclusion:
Caffeine and energy drink use are common, but prevalence depends strongly on product definition and recall period. Evidence supports concern about high-dose or poorly timed exposure and sleep-related associations, but not causal claims about burnout, academic performance or professional impairment. Standardized measures, longitudinal studies and evaluated interventions are needed.
