An interventional study of Placebo and L-Tyrosine in Sports Performance, sponsored by Inonu University. Not yet recruiting at 1 site in Turkey (Türkiye). Open to male participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-07-08.
Sponsored by Inonu University · Not applicable, Interventional, and Basic science
Participants will complete six sessions, including one familiarization and baseline session followed by five experimental conditions: control (no supplementation), placebo, L-tyrosine, caffeine, and combined L-tyrosine plus caffeine. The experimental conditions will be performed in a randomized, counterbalanced crossover design with a washout period of at least 72 hours between sessions. Resting physiological and cognitive assessments will be performed during the familiarization session, while biochemical, cognitive, and boxing-specific performance assessments will be conducted before and after each experimental session.
Participants will attend six sessions in total. The first session will be used for familiarization and baseline assessments, including anthropometric measurements, resting physiological measurements, and cognitive performance testing. The remaining five sessions will consist of one control condition (no supplementation) and four randomized experimental conditions (placebo, L-tyrosine, caffeine, and combined L-tyrosine plus caffeine) administered in a randomized, counterbalanced crossover design.
Each experimental session will be separated by a washout period of at least 72 hours. During the placebo, L-tyrosine, caffeine, and combined supplementation conditions, the assigned intervention will be administered 60 minutes before exercise. No supplement will be administered during the control condition.
Before and immediately after each experimental session, venous blood samples will be collected to assess brain-derived neurotrophic factor (BDNF) and oxidative stress biomarkers, including total antioxidant status (TAS), total oxidant status (TOS), malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPx). Cognitive performance will be evaluated using the computerized Stroop test, and boxing-specific physical performance will be assessed using a standardized boxing simulation protocol. Heart rate and rating of perceived exertion (RPE) will also be recorded during the exercise protocol.
Inonu University is the lead sponsor of 375 studies on the registry; 86 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Male elite boxers aged ≥18 years At least 8 years of boxing training experience Active participation in national or international competitions Regular training schedule No injury or illness affecting performance
Exclusion Criteria:
Use of nutritional supplements or stimulants within the last 4 weeks Any cardiovascular, metabolic, or neurological disorder Current injury or musculoskeletal limitation Smoking or excessive caffeine intake Failure to comply with study procedures
Participants receive placebo condition.
Dietary Supplement: Placebo
Participants receive L-tyrosine condition.
Dietary Supplement: L-Tyrosine
Participants receive caffeine condition.
Dietary Supplement: Caffeine
Participants receive combined supplementation condition.
Dietary Supplement: L-tyrosine + Caffeine
Participants complete the experimental protocol without receiving placebo or active supplementation. Baseline cognitive, physiological, and physical performance assessments are performed under the control condition.
Placebo solution matched in taste and volume to active supplements.
L-tyrosine at 150 mg/kg body weight administered 60 minutes before exercise.
Caffeine at 5 mg/kg body weight administered 60 minutes before exercise.
Combined L-tyrosine (150 mg/kg) and caffeine (5 mg/kg) administered 60 minutes before exercise.
Stroop Test Performance
Cognitive performance assessed using the Stroop test, including reaction time and accuracy.
Time frame: up to 12 weeks
BDNF Levels
Serum brain-derived neurotrophic factor levels measured before and after exercise.
Time frame: up to 12 weeks
Oxidative Stress Markers
Serum levels of total antioxidant status (TAS), total oxidant status (TOS), malondialdehyde (MDA), superoxide dismutase (SOD) activity, and glutathione peroxidase (GPx) activity will be measured.
Time frame: up to 12 weeks
Plan to share: No
No publications or documents are linked to this record.
This study is not yet recruiting, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.
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Inonu University