Drug–protein supplement interactions in young athletes: A scoping review exposing a major evidence gap

Background:  One of the fastest growing consumer segments in the global protein supplement market is the adolescent athlete; this population also regularly uses over-the-counter (OTC) medications such as non-steroidal anti-inflammatory drugs (NSAIDs), antacids and inhaled bronchodilators at the same time. Coadministration of these agents is poorly characterized pharmacokinetically, pharmacodynamically and represents an unmet clinical and public health concern.
Objective:  To systematically map and synthesize published evidence on the prevalence, patterns, and potential clinical consequences of concurrent protein supplement and medication use among athletes aged 14-21 years, also to identify critical gaps that warrant prospective investigation.
Methods: A scoping review was conducted following the PRISMA extension for Scoping Reviews (PRISMA-ScR). We searched PubMed, Scopus and Cochrane Library for articles published between January 1, 2012 and December 31, 2024. Pre-defined inclusion criteria were used to select 18 original peer-reviewed studies involving 13482 young athletes. Study quality was independently assessed by two reviewers using the NIH Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. We used a modified GRADE framework to assess certainty of evidence.
Results: Protein supplement use was reported in 44%–71% of participants across the 18 included studies. Among supplement users, 58%–75% reported concurrent use of at least one medication within the preceding month, with NSAIDs (ibuprofen, naproxen) cited most frequently (35%–50%). Antacids, proton pump inhibitors (PPIs), and inhaled β₂-agonists were the next most common agents. No prospective cohort study has formally assessed clinical outcomes attributable to drug–protein interactions in this population. Fewer than 10% of athletes disclosed supplement–medication co-use to a healthcare professional. The GRADE certainty of evidence for clinically significant drug–protein interactions was rated as very low.
Conclusion: Concurrent use of protein supplements and medications is prevalent among young athletes worldwide, yet remains clinically uncharacterised and largely undisclosed to healthcare professionals. Pharmacists and clinicians should routinely enquire about supplement–medication co-use in this population. Rigorous prospective research is urgently required before evidence-based clinical guidelines can be formulated.