An interventional study of 200 mg S-Acetyl Glutathione and 500 mg S-Acetyl Glutathione in Performance Recovery, Exercise-induced Inflammation and Exercise-induced Oxidative Stress, sponsored by University of Thessaly. Not yet recruiting at 1 site in Greece. Open to participants aged 19 Years to 29 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-07-08.
Sponsored by University of Thessaly · Not applicable, Interventional, and Other
Soccer players display elevated inflammatory and oxidative stress markers combined with reduced soccer specific performance over a 72-hour period. However, in modern soccer, players participate very often in 2 or 3 matches within a week, with a recovery period of 72 hours between successive matches, that is insufficient to restore skeletal muscle homeostasis and performance. Of note, reduced glutathione (GSH) levels, a tripeptide consisting of the amino acids cysteine, glycine and glutamic acid, are substantially reduced during the 72-hour recovery period after a match because of the trauma-related acute inflammatory and oxidative stress response. GSH availability is a crucial regulator of cellular redox status, affecting numerous intracellular and physiological processes such as redox signalling, immunoregulation and muscle metabolism. Indeed, enhanced GSH availability following muscle damaging exercise has been shown to be beneficial for skeletal muscle and performance recovery by mitigating the inflammatory and oxidative stress response. Thus, the enhancement of GSH availability through dietary interventions would be a promising strategy to accelerate skeletal muscle and performance recovery following a soccer game. S-Acetyl Glutathione (SAG) is a glutathione precursor with enhanced absorption kinetics due to chemical S-acetylation of the thiol group on the cysteinyl amino acid of GSH and oral administration of SAG has been shown to be more effective in restoring intracellular glutathione levels compared to oral glutathione. The aim of this study is to (i) perform a pharmacokinetic assessment of 200 mg/day vs 500 mg/day of SAG during a 7-day supplementation period (pre-loading) and (ii) to establish the pharmacodynamic effect of the two dosages at 24, 48 and 72h following a 90-minute official soccer match.
Following baseline testing [including assessment of anthropometrics, body composition (via DXA instrumentation) and physical performance (cardiorespiratory fitness, drop jump and countermovement jump performance, repeated sprint anility, isokinetic peak torque)], 20 well-trained, soccer players will participate in three trials, receiving daily (i) 200 mg SAG, (ii) 500 mg SAG or (iii) Placebo, according to a randomized, double-blind, crossover, repeated-measures design. The duration of each trial will be 11 days, including a 7-day pre-loading period (days 1 -7), a match day (day 8) and 3 consecutive recovery days after the match (days 9-11). Between trials a 3-week washout period will be implemented.
Pre-loading period: During the 7-day pre-loading period players will participate daily in training sessions according to a soccer-specific weekly training schedule, while receiving the respective supplement. Blood samples will be collected on day 1 and day 7 while daily nutrient intake (via 7-day diet recalls), physical activity level (via accelerometry) and training load (via global positioning system instrumentation during training sessions) will be monitored daily.
Match day: On match day, players will participate in an official 90-min soccer match. Field activity (total distance, average and maximum speed, high intensity running, high speed running, accelerations, decelerations) and heart rate (mean and maximum heart rate) will be continuously monitored using global positioning system (GPS) and heart rate monitors, respectively.
Recovery days: During the 3-day recovery period after the match, players will participate daily in (i) morning testing sessions and (ii) training sessions in the evening. Testing sessions will include blood sampling and performance measurements including drop jump and countermovement jump performance, repeated sprint anility, isokinetic peak torque and muscle soreness (DOMS). Dietary intake (via a 3-day diet recalls), physical activity level (via accelerometry) and training load (via GPS instrumentation during training sessions) will be monitored daily.
University of Thessaly is the lead sponsor of 195 studies on the registry; 44 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Oral administration of S-Acetyl Glutathione (SAG)
Dietary Supplement: 200 mg S-Acetyl Glutathione
Oral administration of S-Acetyl Glutathione (SAG)
Dietary Supplement: 500 mg S-Acetyl Glutathione
Oral administration of placebo
Dietary Supplement: Placebo Supplementation
Participants will be supplemented daily with 200 mg of S-acetyl glutathione, orally, over the 11-day experimental period.
Participants will be supplemented daily with 500 mg of S-acetyl glutathione, orally, over the 11-day experimental period.
Participants will be supplemented daily with placebo, orally, over the 11-day experimental period.
Change in creatine kinase levels
Creatine kinase concentration will be measured in serum using a Clinical Chemistry Analyzer
Time frame: Day 1, day 7, day 9, day 10 and day 11
Change in myoglobin levels
Myoglobin concentration will be measured in serum using a Clinical Chemistry Analyzer
Time frame: Day 1, day 7, day 9, day 10 and day 11
Change in reduced glutathione
Reduced glutathione will be photometrically determined in red blood cell lysates using a spectrophotometer
Time frame: Day 1, day 7, day 9, day 10 and day 11
Change in oxidized glutathione
Oxidized glutathione will be photometrically determined in red blood cell lysates using a spectrophotometer
Time frame: Day 1, day 7, day 9, day 10 and day 11
Change in glutathione reductase activity
Glutathione reductase activity will be photometrically determined in red blood cell lysates using a spectrophotometer
Time frame: Day 1, day 7, day 9, day 10 and day 11
Change in glutathione peroxidase activity
Glutathione peroxidase activity will be photometrically determined in red blood cell lysates using a spectrophotometer
Time frame: Day 1, day 7, day 9, day 10 and day 11.
Change in catalase activity
Catalase activity will be photometrically determined in red blood cell lysates using a spectrophotometer
Time frame: Day 1, day 7, day 9, day 10 and day 11
Change in superoxide dismutase activity
Superoxide dismutase activity will be photometrically determined in red blood cell lysates using a spectrophotometer
Time frame: Day 1, day 7, day 9, day 10 and day 11
Change in maximal voluntary isometric contraction
Maximal voluntary isometric contraction will be assessed at a 60o knee joint angle, in both dominant and non-dominant limb, using an isokinetic dynamometer
Time frame: Day 1, day 9, day 10 and day 11
Change in maximal peak torque
Maximal concentric and eccentric peak torque at 60o/s of the knee extensors and flexors in both dominant and non-dominant limb, will be assessed on an isokinetic dynamometer
Time frame: Day 1, day 9, day 10 and day 11
Change in jumping performance
Countermovement jump and drop jump performance will be tested using an optical measurement system consisting of a transmitting and receiving bar
Time frame: Day 1, day 9, day 10 and day11
Change in repeated sprint ability
Repeated sprint ability will be assessed by performing 5x25 m sprints interspersed by a 25-seconds recovery period using infrared photocells
Time frame: Day 1, day 9, day 10 and day 11
Change in delayed onset muscle soreness (DOMS)
DOMS will be assessed using a 10-scale visual analogue scale
Time frame: Day 1, day 9, day 10 and day 11
Change in total distance covered
Total distance (km) covered during training and match play will be monitored using Global Positioning System (GPS)
Time frame: Daily throughout the 11-day experimental period
Change in internal load
Heart rate during training sessions and the match will be monitored using heart rate monitors
Time frame: Daily throughout the 11-day experimental period
Change in dietary intake
Dietary intake will be assessed using diet recalls
Time frame: Daily throughout the 11-day experimental period
Change in time spent in moderate-to-vigorous physical activity
The time (minutes) spent in moderate-to-vigorous physical activity on a daily basis will be monitored using accelerometers
Time frame: Daily throughout the 11-day experimental period
Change in distance covered with high-intensity running
Distance (km) covered with high-intensity running during training and match play will be monitored using Global Positioning System (GPS)
Time frame: Daily throughout the 11-day experimental period
Change in distance covered with sprinting
Distance (km) covered with high-intensity sprinting during training and match play will be monitored using Global Positioning System (GPS)
Time frame: Daily throughout the 11-day experimental period
Change in accelerations
The number of accelerations performed during training and match play will be monitored using Global Positioning System (GPS)
Time frame: Daily throughout the 11-day experimental period
Change in decelerations
The number of decelerations performed during training and match play will be monitored using Global Positioning System (GPS)
Time frame: Daily throughout the 11-day experimental period
Change in total step count
The total number of steps performed daily will be monitored using accelerometers
Time frame: Daily throughout the 11-day experimental period
Change in physical activity-related energy expenditure
Energy expenditure (kcal) related to habitual physical activity will be assessed using accelerometers
Time frame: Daily throughout the 11-day experimental period
Plan to share: No
No publications or documents are linked to this record.
This study is not yet recruiting, as verified in May 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.