NCT07530185

Effects of L-Tyrosine and Caffeine on Performance in Elite Boxers

Effects of L-Tyrosine and Caffeine Supplementation on Cognitive, Physical, and Physiological Parameters in Elite Boxers: A Randomized Double-Blind Placebo-Controlled Crossover Study

• Status: Not Yet Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 18 (estimated)
• Sponsor: Inonu University · Academic / Other
• Sex: Male
• Age: 18 Years
• Healthy volunteers: Accepted

Summary

Participants will complete five sessions, including one familiarization and baseline session and four experimental conditions (placebo, L-tyrosine, caffeine, and combined supplementation). The baseline session will include resting measurements. The experimental conditions will be performed in a randomized, counterbalanced crossover design with a washout period of at least 72 hours between sessions.

Detailed description

Participants will attend five sessions in total. The first session will be used for familiarization and baseline measurements, including resting physiological and cognitive assessments. The remaining four sessions will consist of randomized experimental conditions (placebo, L-tyrosine, caffeine, and combined supplementation), applied in a counterbalanced crossover design. Each experimental session will be separated by a washout period of at least 72 hours. Supplements will be administered 60 minutes before exercise. Cognitive performance will be assessed using the Stroop test, and physical performance will be evaluated using a boxing-specific simulation protocol. Physiological responses, including heart rate and biochemical markers such as BDNF and oxidative stress parameters, will be measured.

Conditions

• Sports Performance

Interventions

Type	Name	Description
DIETARY_SUPPLEMENT	Placebo	Placebo solution matched in taste and volume to active supplements.
DIETARY_SUPPLEMENT	L-Tyrosine	L-tyrosine at 150 mg/kg body weight administered 60 minutes before exercise.
DIETARY_SUPPLEMENT	Caffeine	Caffeine at 5 mg/kg body weight administered 60 minutes before exercise.
DIETARY_SUPPLEMENT	L-tyrosine + Caffeine	Combined L-tyrosine (150 mg/kg) and caffeine (5 mg/kg) administered 60 minutes before exercise.

Timeline

• Start date: 2026-04-01
• Primary completion: 2026-12-01
• Completion: 2027-03-01
• First posted: 2026-04-15
• Last updated: 2026-04-15

Locations

1 site across 1 country: Turkey (Türkiye)