This randomized, double-blind, placebo-controlled trial will compare magnesium glycinate, magnesium L-threonate, and placebo in UCLA varsity athletes. Participants will complete a baseline monitoring period followed by 4 weeks of blinded nightly supplementation. WHOOP or study-approved wearable data will be used to evaluate sleep efficiency, total sleep time, sleep consistency, heart rate variability, resting heart rate, and recovery metrics. Baseline and final testing will assess selected reaction and physical performance outcomes. The primary outcome is change in WHOOP-derived sleep efficiency from baseline week to final treatment week.
Magnesium is involved in neuromuscular signaling, cellular energy metabolism, autonomic regulation, and sleep-related physiology. Competitive athletes often experience sleep restriction, training stress, travel, soreness, and recovery demands. Magnesium glycinate and magnesium L-threonate are commonly used athlete-facing magnesium formulations, but they are not interchangeable. Glycinate is commonly positioned as a well-tolerated sleep-oriented formulation, whereas L-threonate is of interest because of prior signals related to sleep, cognition, reaction performance, and central nervous system magnesium biology. This single-site UCLA study will enroll adult varsity athletes aged 18 to 35 years. Participants will complete screening, informed consent, baseline assessments, wearable monitoring, a baseline monitoring period, randomization in a 1:1:1 ratio, 4 weeks of blinded nightly capsules, brief daily REDCap morning surveys, weekly adherence and safety check-ins, and final performance-adjacent testing. The primary outcome is change in average WHOOP-derived sleep efficiency from baseline week to final treatment week. Prespecified primary contrasts will compare magnesium glycinate versus placebo and magnesium L-threonate versus placebo. Total sleep time, sleep consistency, resting heart rate, heart rate variability, WHOOP Recovery Score, reaction-time performance, grip strength, countermovement jump height, adherence, tolerability, and adverse events will be analyzed as secondary or exploratory outcomes according to the final statistical analysis plan. The magnesium glycinate versus magnesium L-threonate contrast will be treated as exploratory unless the final statistical analysis plan preserves alpha for that comparison.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
QUADRUPLE
Enrollment
150
Blinded oral magnesium glycinate capsules taken nightly for 28 days.
Blinded oral magnesium L-threonate capsules taken nightly for 28 days.
Matching placebo capsules taken nightly for 28 days.
University of California, Los Angeles
Los Angeles, California, United States
Change in WHOOP-derived sleep efficiency percentage from baseline week to final treatment week
Average nightly WHOOP-derived sleep efficiency, expressed as a percentage, will be calculated for the baseline week and final treatment week. A valid week requires at least 5 usable nights in the 7-day window. The outcome is final-treatment-week average minus baseline-week average; higher values indicate improved sleep efficiency.
Time frame: Baseline week to final treatment week, approximately 5 weeks total including baseline monitoring
Change in BlazePod RIW Challenge reaction time in milliseconds from baseline to final visit
Reaction performance will be measured using the prespecified BlazePod RIW Challenge protocol. The outcome is change in reaction time in milliseconds from baseline to final visit. Lower reaction time indicates better performance.
Time frame: Baseline to final visit, approximately 5 weeks
Change in BlazePod Speed Tap reaction time in milliseconds from baseline to final visit
Reaction performance will be measured using the prespecified BlazePod Speed Tap protocol. The outcome is change in reaction time in milliseconds from baseline to final visit. Lower reaction time indicates better performance.
Time frame: Baseline to final visit, approximately 5 weeks
Change in WHOOP-derived sleep consistency score from baseline week to final treatment week
WHOOP-derived sleep consistency score, or an equivalent prespecified wearable-derived sleep timing regularity metric, will be summarized for the baseline week and final treatment week. The outcome is final-treatment-week average minus baseline-week average.
Time frame: Baseline week to final treatment week, approximately 5 weeks total including baseline monitoring
Change in WHOOP-derived total sleep time in minutes from baseline week to final treatment week
Average nightly total sleep time captured by WHOOP, expressed in minutes, will be calculated for the baseline week and final treatment week. The outcome is final-treatment-week average minus baseline-week average.
Time frame: Baseline week to final treatment week, approximately 5 weeks total including baseline monitoring
Change in WHOOP-derived resting heart rate in beats per minute from baseline week to final treatment week
Nightly resting heart rate captured by WHOOP, expressed in beats per minute, will be summarized as weekly averages for the baseline week and final treatment week. The outcome is final-treatment-week average minus baseline-week average.
Time frame: Baseline week to final treatment week, approximately 5 weeks total including baseline monitoring
Change in WHOOP-derived heart rate variability in milliseconds from baseline week to final treatment week
Nightly heart rate variability captured by WHOOP, expressed in milliseconds, will be summarized as weekly averages for the baseline week and final treatment week. The outcome is final-treatment-week average minus baseline-week average.
Time frame: Baseline week to final treatment week, approximately 5 weeks total including baseline monitoring
Change in WHOOP Recovery Score from baseline week to final treatment week
WHOOP Recovery Score, reported on a 0 to 100 scale where higher scores indicate better recovery, will be summarized as weekly averages for the baseline week and final treatment week. The outcome is final-treatment-week average minus baseline-week average.
Time frame: Baseline week to final treatment week, approximately 5 weeks total including baseline monitoring
Change in VALD dynamometer bilateral average handgrip strength from baseline to final visit
Bilateral average handgrip strength will be measured with the prespecified VALD handgrip dynamometer protocol. The outcome is final-visit bilateral average handgrip strength minus baseline bilateral average handgrip strength.
Time frame: Baseline to final visit, approximately 5 weeks
Change in VALD force plate countermovement jump height from baseline to final visit
Countermovement jump height will be measured with the prespecified VALD force plate protocol. The outcome is final-visit jump height minus baseline jump height.
Time frame: Baseline to final visit, approximately 5 weeks
Number of participants with adverse events and supplement tolerability concerns
The number of participants with adverse events, tolerability concerns, dose interruptions, and study-product discontinuations will be summarized by study arm. Events of interest include gastrointestinal symptoms, sedation, dizziness, headache, allergic reaction, skin irritation from wearable use, and study-product discontinuation.
Time frame: From first dose through final visit, approximately 4 weeks
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