Michailidis 2013.

Methods	Randomised, double‐blind (cross‐over design) 6 weeks washout period
Participants	Setting: laboratory, Greece n = 10 male recreationally active Mean age 23.5 (SD 2.5) years Inclusion/exclusion criteria Participants were recreationally trained, as evidenced by their maximal oxygen consumption (O2max) level (> 45 mL · kg−1 · min−1); had been engaged in systematic exercise ≥ 3 times/week for ≥ 12 months, and were non‐smokers. Participants abstained from any vigorous physical activity and the consumption of caffeine, alcohol or performance‐enhancing or antioxidant supplements and medications before (6 months) and during the exercise trials. Exclusion criteria included a known NAC intolerance or allergy, a recent febrile illness and history of muscle lesion and lower limb trauma.
Interventions	Intervention 20 mg NAC/kg per day was administered orally (Uni‐Pharma) in 3 daily dosages. NAC was dissolved in a 500 mL drink that contained water (375 mL), a sugar‐free cordial (125 mL) and a 2 g low‐calorie glucose/dextrose powder to improve palatability Placebo Placebo solution was formulated to be identical to the NAC solution, except for the NAC content Duration Supplement consumed immediately after muscle‐damaging exercise and for 8 days post‐exercise
Outcomes	PRIMARY Delayed onset of muscle soreness (delayed onset muscle soreness) was determined by palpation of the muscle belly and the distal region of the vastus medialis, vastus lateralis and rectus femoris after a squat. Perceived soreness was rated on a scale ranging from 1 (normal) to 10 (very, very sore). SECONDARY Maximal knee extensor eccentric peak torque at 60°/second on an isokinetic dynamometer (Isoforce)
Exercise type	300 eccentric unilateral repetitions (20 sets, 15 repetitions/set, 30‐second rest between sets) with the quadriceps muscle group at a speed of 30°/second on an Isoforce (TUR Gmbh) isokinetic dynamometer
Sources of funding	Manuscript states: "Supported by departmental funding, a grant received by Bodosakis Foundation (Greece) for instrument purchase, and grant funding (CE‐80739). APR was supported by a National Health and Medical Research Council Career Development Award, Australia."
Notes	Authors were contacted on 7 February 2017 to request data for delayed onset muscle soreness and maximal voluntary isometric contraction but did not respond
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No details in manuscript Authors were contacted on 7 February 2017 but did not respond
Allocation concealment (selection bias)	Unclear risk	No details in manuscript Authors were contacted on 7 February 2017 but did not respond
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Manuscript states the design was double‐blind
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Double‐blind
Incomplete outcome data (attrition bias) All outcomes	High risk	Protocol states 20 individuals were enrolled and 12 completed. Manuscript states that 10 males completed the study.
Selective reporting (reporting bias)	Low risk	Published protocol available (ClinicalTrials.gov identifier: NCT01778309) All data reported at all time points Manuscript states: "Participants reported no adverse side effects attributed to NAC consumption"
Other bias	Unclear risk	5‐day diet recalls (1 recall/day) were completed before each trial and standardised between trials No information on NSAIDs