UCLA Magnesium Formulation Athlete Study

Inclusion Criteria: * Age 18 to 35 years. * Current UCLA varsity athlete. * Actively training or competing during the study period. * Willing to wear WHOOP or a study-approved wearable device continuously during baseline and treatment periods if wearable data are used. * Willing to take assigned study capsules nightly for 28 days. * Willing to complete brief daily REDCap surveys and weekly adherence/safety check-ins. * Able to provide informed consent and comply with study procedures. Exclusion Criteria: * Current magnesium supplementation without completion of an appropriate washout before baseline. * Current investigational drug or investigational supplement use. * Current use of prescription or over-the-counter sleep medications unless reviewed and permitted by the study clinician. * Diagnosed sleep disorder that, in the investigator's judgment, would confound outcomes or increase risk. * Significant kidney disease or another medical condition that may increase risk with magnesium supplementation. * Known intolerance or allergy to magnesium glycinate, magnesium L-threonate, placebo, or inactive study ingredients. * Use of medications with clinically relevant magnesium interactions unless reviewed and permitted by the study clinician. * Any other condition that, in the investigator's judgment, would make participation unsafe, compromise voluntary consent, or prevent valid outcome assessment.