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Completed

NCT Number: NCT05604586

Assessment of the Impact of N-acetylcysteine Supplementation on Physical Performance

Study aims to verify the hypothesis:

* N-acetylcysteine (NAC) supplementation improves exercise capacity in people training endurance sports and the effectiveness of this supplementation depends on the polymorphism of genes related to folate and glutathione metabolism. * NAC supplementation affects the parameters of oxidative stress among women and men training endurance disciplines

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Key information

Age range

18 year–45 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Poznan University of Life Science

Poznan, Poland

About this study

  • Glutathione depletion caused by a combination of intense physical exertion associated with the generation of significant amounts of reactive oxygen species (ROS), and possibly with having an unfavorable variant of the methylenetetrahydrofolate reductase (MTHFR), glutamate-cysteine ligase catalytic subunit (GCLC); glutamate-cysteine ligase modifier subunit (GCLM); glutathione S-transferase Pi 1 (GSTP1); glutathione synthetase (GSS) or cystathionine-β-synthase (CBS) genes may contribute to lower adaptation to exercise, but also to deterioration of health of people training endurance sports.
  • The main objective of the study is to verify the hypothesis that NAC supplementation has a beneficial effect on regeneration between intense exercise tests simulating a race characteristic for a given discipline. In addition, this study is aimed at checking whether genotype may modify the effectiveness of the supplementation measured as exercise and biochemical parameters . A double-blind study involving 100 women and men supplementing 1200 mg of N-acetylcysteine daily or 1200 mg of rice flour in three equal doses. Supplementation will last for 7 days. Blood sampling and body composition testing will be performed in the morning of the exercise test day. Discipline-specific exercise testing will be performed before and after the intervention.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Consent to participate in the study and acceptance of the established scheme for conducting the intervention
  • age range between 18 and 45 years old
  • regular training with a frequency of at least 3 times a week during the last year,

Exclusion criteria

  • no consent to participate in the study and no acceptance of the established scheme of the conducted intervention
  • existing diseases of the blood system and neoplastic diseases
  • respiratory system diseases
  • obesity
  • any medical contraindications to exercise
  • Results obtained from exercise tests that do not meet the inclusion criteria
  • use of NAC during the last month
  • allergy to NAC
  • smoking
  • pregnancy and lactation

Treatment and study plan

N-acetylcysteine

Dietary Supplement

100 women and men supplementing 1200 mg of N-acetylcysteine daily in three equal doses. Supplementation will last for 7 days.

Placebo

Dietary Supplement

100 women and men supplementing 1200 mg of placebo daily in three equal doses. Supplementation will last for 7 days.

Primary outcomes

  1. Assesment of change in results of time trial test

    Time frame: Baseline,1 week

    (min/test) change within groups and between groups

Secondary outcomes

  1. Reduced glutathione (GSH)

    Time frame: Baseline,1 week

    GSH (µM) concentrations change within the group and between the groups

  2. Oxidized glutathione (GSSG)

    Time frame: Baseline,1 week

    GSSG (µM) concentrations change within the group and between the groups

  3. Homocysteine (Hcy)

    Time frame: Baseline,1 week

    Hcy (µmol/l) concentrations change within the group and between the groups

  4. Total cholesterol (TChol)

    Time frame: Baseline,1 week

    TChol (mg/dl) concentrations change within the group and between the groups

  5. Blood HDL-cholesterol (HDL-C)

    Time frame: Baseline,1 week

    HDL-C (mg/dl) concentrations change within the group and between the groups

  6. Blood LDL-cholesterol (LDL-C)

    Time frame: 1 week

    LDL-C (mg/dl) concentrations change within the group and between the groups

  7. Blood triacylglycerol (TAG)

    Time frame: Baseline,1 week

    TAG (mg/dl) concentrations change within the group and between the groups

  8. Dietary intake

    Time frame: Baseline,1 week

    macro and micronutrient intake (g,mg,ug)

  9. aspartate aminotransferase (ASPAT)

    Time frame: 1 week

    ASPAT [U/l] Changes within groups and between groups

  10. Alanine transaminase (ALAT)

    Time frame: Baseline,1 week

    ALAT [U/l] change within groups and between groups

  11. Oxygen volume (VO2)

    Time frame: Baseline,1 week

    VO2 (ml/kg bw./min) change within groups and between groups

  12. Carbon dioxide volume (VCO2)

    Time frame: Baseline,1 week

    VCO2 (ml/kgm.c./min) change within groups and between groups

  13. Testosterone (T)

    Time frame: Baseline,1 week

    T (ng/dL) concentrations change within the group and between the groups

  14. Cortisol (C)

    Time frame: Baseline,1 week

    C (ng/dL) concentrations change within the group and between the groups

  15. Body mass(BM)

    Time frame: Baseline, 1 week

    Change in BM (kg) within groups and between groups

  16. Fat Free Mass (FFM)

    Time frame: Baseline, 1 week

    FFM change within (kg) groups and between groups

  17. Fat Mass% (FM%)

    Time frame: Baseline, 1 week

    FM% change within groups and between groups

  18. Thiobarbituric Acid Reactive Species (TBARS)

    Time frame: 1 week

    TBARS concentrations change within the group and between the groups

Sponsors and collaborators

Lead sponsor

Poznan University of Life Sciences

Other

Registry information

Official study title

Assessment of the Impact of N-acetylcysteine Supplementation on Physical Performance Depending on the Polymorphism of Genes Related to Glutathione Metabolism

Important dates

Study start
2022
Primary completion
2025
Study completion
2025
First posted
Nov 3, 2022
Registry last updated
Jun 10, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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