Abstract Body (Do not enter title and authors here): Introduction:
Performance-enhancing supplements have been linked to several detrimental cardiovascular events including demand ischemia, tachyarrhythmias, and sudden cardiac death. However, cases of myopericarditis have seldom been reported. We present a case of a previously healthy young male with myopericarditis secondary to performance-enhancing supplements.

Case presentation:
Patient is a 33-year-old athletic male with no significant medical history who presented with severe retrosternal chest pain and exertional dyspnea. The patient was athletic and used multiple performance-enhancing supplements including SERMs, TRT, thermogenic fat burner, Cardarine, and a caffeinated pre-workout. Labs were notable for a peak hs-cTn of 391. An EKG showed sinus rhythm with new onset incomplete RBBB, nonspecific T wave inversions, and ST deviations. A TTE revealed an EF of 45-50% and diffuse hypokinesia. He was subsequently admitted as a case of NSTEMI. The patient underwent left heart catheterization which revealed no evidence of CAD. Myopericarditis was confirmed by CMR which demonstrated late enhancement and increased T1 and T2 mapping. Biventricular systolic dysfunction was also noted with a left and right ventricular EF of 43% and 34% respectively. The patient was diagnosed with HFmrEF and discharged on GDMT; metoprolol succinate and lisinopril.

Discussion:
Despite the widespread use and accessibility of performance-enhancing supplements, the body of literature regarding their cardiovascular effects remains insubstantial. Their suspected cardiotoxic effects are not solely attributed to their inherent adverse properties but also from frequent product contamination with other cardiotoxic agents, such as heavy metals, introduced through substandard manufacturing practices. Furthermore, these supplements are frequently used in combination, further potentiating their adverse effects. A significant consideration is the lack of FDA testing to verify label accuracy leaving consumers without vital information on ingredients, dosages, and possible interactions thus subjecting them to undisclosed hazards. A thorough examination of regulatory testing in the supplement industry could yield a positive impact on public health and facilitate the establishment of guidelines for safe and effective usage. We hope that as the body of evidence continues to grow, we can better evaluate the effects of individual supplements and their potential interactions when used concomitantly.