Redox Status and Exercise Training-induced Adaptations

Effects of N-acetylcysteine on Biological Responses to High-intensity Interval Training in Adults With Overweight/Obesity

Excess fat accumulation is a key feature of overweight and obesity that is mainly driven by nutrient overload and insufficient physical activity. White adipose tissue displays lipid overload and hypertrophy accompanied by macrophages infiltration, hypoxia, inflammation and excess production of reactive oxygen species (ROS). An inflammatory response and ROS production are also evident in other metabolism regulating tissues and organs such as skeletal muscle, liver, pancreas and hypothalamus, contributing to a chronic inflammatory state, redox status disturbances and metabolic complications. There is overwhelming evidence showing that adults with overweight/obesity exhibit lower glutathione (GSH) levels in blood erythrocytes, skeletal muscle cells and subcutaneous and visceral adipose tissue cells. GSH, a tripeptide consisting of the amino acids glutamate, cysteine and glycine, is the most abundant thiol-containing antioxidant in the human body and has been, recently, characterized as a novel therapeutic target for the treatment of numerous chronic diseases, due to its potent intracellular redox buffering capacity. Interestingly, lower GSH levels have been associated with diet-induced weight loss resistance, while enhancement of GSH levels through N-acetylcysteine (NAC) supplementation reduces markers of oxidative stress, inflammation, insulin resistance, hypertension, endothelia dysfunction and improves vitamin D metabolism. NAC is a thiol donor that elicits antioxidant effects by (i) directly scavenging ROS and (ii) providing reduced cysteine through deacetylation, which supports the biosynthesis of endogenous GSH via the activity of γ-glutamylcysteine synthase. The aim of this study is to investigate whether NAC supplementation can enhance the exercise training-induced improvements on physical fitness and metabolic health in adult men and women with overweight/obesity.

Study Overview

• Status: Recruiting
• Conditions: Obesity; Overweight (BMI > 25)
• Intervention / Treatment: Dietary supplement: N Acetyl L Cysteine; Dietary supplement: Placebo

Detailed Description

Forty adults with overweight/obesity (both males and females, aged 35-45 years) who will meet the inclusion criteria will be randomly assigned to a Placebo (Pla, n=20, will be supplemented with 2 placebo pills daily over a 12-week period) or a NAC (NAC, n=20 will be supplemented with 2 pills x 600 mg N-acetylcysteine daily over a 12-week period) group. Both groups will participate in 3 multicomponent high-intensity interval training (m-HIIT) sessions per week over a 12-week period. At baseline, 6 weeks and 12 weeks participants will undergo assessment of their (i) anthropometrics (body weight, waist and hip circumferences) (ii) body composition (through total body DXA scan), (iii) fat liver content (via high-resolution ultrasound), (iv) cardiorespiratory fitness (determination of VO2max), (v) muscle strength (upper and lower body), (vi) habitual physical activity level (via accelerometry) and (vii) daily dietary intake (via dietary recalls). In addition, at the same time-points (Baseline, 6 weeks, 12 weeks), resting blood samples will be collected for the determination of (viii) blood redox status [reduced glutathione (GSH), oxidized glutathione (GSSH), GSH/GSSG, glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD) and catalase (CAT)], (ix) peripheral blood mononuclear cells antioxidant levels and markers of oxidative stress and inflammation (catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, malondialdehyde, TNF-α and Interleukin-6), (x) low-grade systemic inflammation [C-reactive protein (CRP) and Interleukin-6 (IL-6)], (xi) lipidemic profile (triglycerides, total cholesterol, HDL, LDL) and (xii) liver function (SGPT, SGOT, γ-GT, ALP, Fetuin-A), and (xiii) an oral glucose tolerance test (using 75g glucose loading) will be performed.

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Dimitrios Draganidis, PhD; Phone Number: +30 2431047078; Email: ddraganidis@uth.gr
• Study Contact Backup: Name: Ioannis G. Fatouros, PhD; Phone Number: +30 2431047047; Email: ifatouros@uth.gr

Study Locations

• Greece
  • Karies
    • Trikala, Karies, Greece, 42100
      • Recruiting
      • Department of Physical Education and Sport Science, University of Thessaly
      • Contact: Dimitrios Draganidis, PhD; Phone Number: +30 2431047078; Email: ddraganidis@uth.gr
      • Contact: Ioannis G. Fatouros, PhD; Phone Number: +30 2431047047; Email: ifatouros@uth.gr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• BMI 25-35 kg/m2
• Free of musculoskeletal injuries
• Free of chronic non-communicable diseases
• Do not receive any drug therapy
• Do not receive dietary supplements
• Normal menstrual cycle (for females)
• Non smokers

Exclusion Criteria:

• NAC intolerance
• Bleeding disorders
• Kidney disease
• Asthma
• Usage of blood thinners and/or angina medication

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: N-acetylcysteine; Oral N-acetylcysteine supplementation for 12 weeks (2 x 600 mg capsules/day)	Dietary supplement: N Acetyl L Cysteine; Participants will participate in 3 multicomponent high-intensity interval training (m-HIIT) sessions per week over a 12-week period while receiving daily 1200 mg N-acetylcysteine (2 pills x 600 mg/day ).
Placebo Comparator: Placebo; Oral placebo supplementation for 12 weeks (2 placebo capsules/day)	Dietary supplement: Placebo; Participants will participate in 3 multicomponent high-intensity interval training (m-HIIT) sessions per week over a 12-week period while receiving daily 2 placebo pills/day.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in body weight (kg)		At baseline, 6 weeks and 12 weeks
Change in waist circumference		At baseline, 6 weeks and 12 weeks
Change in hip circumference		At baseline, 6 weeks and 12 weeks
Change in fat mass (kg)	Fat mass will be assessed through dual energy X-ray absorptiometry (DXA)	At baseline, 6 weeks and 12 weeks
Change in body fat percent (%)	Body fat percent will be assessed through dual energy X-ray absorptiometry (DXA)	At baseline, 6 weeks and 12 weeks
Change in fat free mass (kg)	Fat free mass will be assessed through dual energy X-ray absorptiometry (DXA)	At baseline, 6 weeks and 12 weeks
Change in lean body mass (kg)	Lean body mass will be assessed through dual energy X-ray absorptiometry (DXA)	At baseline, 6 weeks and 12 weeks
Change in liver fat infiltration	Liver fat infiltration will be assessed through ultrasound elastography	At baseline and 12 weeks
Change in cardiorespiratory fitness	Maximal oxygen consumption (VO2max) will be estimated during a single stage treadmill test (Ebbeling single stage test)	At baseline, 6 weeks and 12 weeks
Change in lower body muscle strength	Maximal concentric peak torque will be assessed on an isokinetic dynamometer	At baseline, 6 weeks and 12 weeks
Change in upper body muscle strength	Upper body muscle strength will be assessed through the abdominal strength test and the push-up test	At baseline, 6 weeks and 12 weeks
Change in reduced glutathione (GSH) concentration	GSH concentration will be determined in blood erythrocytes and peripheral blood mononuclear cells	At baseline, 6 weeks and 12 weeks
Change in oxidized glutathione (GSSG) concentration	GSSG concentration will be determined in blood erythrocytes and peripheral blood mononuclear cells	At baseline, 6 weeks and 12 weeks
Change in glutathione peroxidase (GPx) activity	GPx activity will be determined in blood erythrocytes and peripheral blood mononuclear cells	At baseline, 6 weeks and 12 weeks
Change in glutathione reductase (GR) activity	GR activity will be determined in blood erythrocytes and peripheral blood mononuclear cells	At baseline, 6 weeks and 12 weeks
Change in catalase activity	Catalase activity will be determined in blood erythrocytes and peripheral blood mononuclear cells	At baseline, 6 weeks and 12 weeks
Change in superoxide dismutase (SOD) activity	SOD activity will be determined in blood erythrocytes and peripheral blood mononuclear cells	At baseline, 6 weeks and 12 weeks
Change in C-reactive protein (CRP) concentration		At baseline, 6 weeks and 12 weeks
Change in TNF-α concentration	TNF-α concentration will be determined in blood and peripheral blood mononuclear cells	At baseline, 6 weeks and 12 weeks
Change in interleukin-6 (IL-6) concentration	IL-6 concentration will be determined in blood and peripheral blood mononuclear cells	At baseline, 6 weeks and 12 weeks
Change in HDL cholesterol concentration	HDL cholesterol concentration will be determined in blood	At baseline, 6 weeks and 12 weeks
Change in LDL cholesterol concentration	LDL cholesterol concentration will be determined in blood	At baseline, 6 weeks and 12 weeks
Change in total cholesterol concentration	Total cholesterol concentration will be determined in blood	At baseline, 6 weeks and 12 weeks
Change in triglycerides concentration	Triglycerides concentration will be determined in blood	At baseline, 6 weeks and 12 weeks
Change in serum glutamic-oxaloacetic transaminase (SGOT/AST) concentration	SGOT concentration will be determined in blood	At baseline, 6 weeks and 12 weeks
Alanine Aminotransferase (SGPT/ALT) concentration	SGPT concentration will be determined in blood	At baseline, 6 weeks and 12 weeks
Change in Gamma-glutamyl transpeptidase (γ-GT) concentration	γ-GT concentration will be determined in blood	At baseline, 6 weeks and 12 weeks
Change in fetuin-A concentration	Fetuin-A concentration will be determined in blood	At baseline, 6 weeks and 12 weeks
Change in alkaline phosphatase (ALP) concentration	ALP concentration will be determined in blood	At baseline, 6 weeks and 12 weeks
Change in glucose concentration	Glucose concentration will be determined in blood	At baseline, 6 weeks and 12 weeks
Change in glycated hemoglobin (HbA1c) concentration	HbA1c concentration will be determined in blood	At baseline, 6 weeks and 12 weeks
Change in insulin concentration	Insulin concentration will be determined in blood	At baseline, 6 weeks and 12 weeks
Change in malondialdehyde concentration	Malondialdehyde concentration will be determined in peripheral blood mononuclear cells	At baseline, 6 weeks and 12 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in dietary intake	Dietary intake will be monitored through diet recalls	At baseline, 6 weeks and 12 weeks
Change in total number of steps	Total number of steps performed per day will be assessed by using accelerometers	At baseline, 6 weeks and 12 weeks
Change in time spent in moderate-to-vigorous physical activity	The time spent in moderate-to-vigorous physical activity per day will be assessed by using accelerometers	At baseline, 6 weeks and 12 weeks

Collaborators and Investigators

• Sponsor: University of Thessaly
• Investigators: Principal Investigator: Anastasia Rosvoglou, PhDc, University of Thessaly, Department of Physical Education and Sport Science; Study Director: Dimitrios Draganidis, PhD, University of Thessaly, Department of Physical Education and Sport Science

Study record dates

Study Major Dates

• Study Start (Actual): September 22, 2025
• Primary Completion (Estimated): June 30, 2026
• Study Completion (Estimated): December 30, 2026

Study Registration Dates

• First Submitted: September 19, 2025
• First Submitted That Met QC Criteria: September 19, 2025
• First Posted (Estimated): September 29, 2025

Study Record Updates

• Last Update Posted (Actual): December 16, 2025
• Last Update Submitted That Met QC Criteria: December 9, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: obesity; overweight; N-acetylcysteine; high-intensity interval training
• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Overweight; Obesity; Amino Acids, Peptides, and Proteins; Sulfur Compounds; Organic Chemicals; Amino Acids; Cysteine; Amino Acids, Sulfur; Acetylcysteine
• Other Study ID Numbers: UTH-2568_2.4.2025

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No