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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Bioavailability of orally administered gamma-glutamylcysteine
Scientific title
Bioavailability study to determine whether a single oral dose of gamma-glutamylcysteine (GGC) sodium salt can transiently increase glutathione content of the white blood cells and brain tissue of healthy volunteers.
Secondary ID [1] 281161 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
This bioavailability trial represents an initial investigation in healthy volunteers to determine the potential of gamma-glutamylcysteine (GGC) to augment cellular glutathione levels. Glutathione depletion is associated with numerous age related disorders. 287326 0
Condition category
Condition code
Other 287662 287662 0 0
Conditions of unknown or disputed aetiology (such as chronic fatigue syndrome/myalgic encephalomyelitis)

Study type
Description of intervention(s) / exposure
On separate days with a one week washout, participants will receive double blinded single oral doses of gamma-glutamylcysteine (GGC) in the range of 250 mg to 4g (placebo control glucose) . Participants will range from 18 to 20 years, with the only exclusions being smokers, pregnancy, and metal medical implants (MRI). Glutathione levels will be monitored periodically for up to 7 hours following administration by the taking of blood samples (lymphocyte glutathione content) and/or by MRI/MRS (brain tissue content).
Intervention code [1] 285610 0
Treatment: Drugs
Comparator / control treatment
The experimental design will involve a randomized double blind crossover group, dose comparison procedure. To mask the dosage level, all patients will receive sixteen 250 mg capsules for each tested dose with the capsules containing either gamma-glutamylcysteine or glucose (placebo). Both groups of gelatin capsules will be identical .
Control group

Primary outcome [1] 287909 0
The lymphocytes will be isolated from blood samples using the Ficoll Paque PLUS based method. Following isolation the lymphocytes will be purified and counted using an automated cell sorter with morphology based gating to dispense 10^6 cells per well (96 well microtitre plate) in triplicate. The cells will be lysed and assayed using a Promega glutathione assay kit (luciferase based luminescence detection).
Timepoint [1] 287909 0
Pre-dosage and at 90, 180, 360, 450, and 540 minutes
Primary outcome [2] 304686 0
Changes in glutathione levels in brain tissue will be determined by Magnetic Resonance Imaging/Spectroscopy (MRI/MRS) scans.
Timepoint [2] 304686 0
Basal (initial) glutathione levels will be determined by a MRI/MRS scan (15 -
20 min) prior to GGC administration. Participants will be further scanned at 2, 4, and 7 hours,
Secondary outcome [1] 299040 0
Timepoint [1] 299040 0

Key inclusion criteria
Aged 20 - 80 years, reasonable health, non-smoker, non alcoholic, not pregnant, and not surgically fitted with metal medical devices (e.g. pace makers, Cochlear implants) .
Healthy body weight [body mass index (BMI) 18.5 - 25 kg/m2]
Minimum age
20 Years
Maximum age
80 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
smokers, alcoholics, any illnesses requiring regular medication

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Participants will be volunteers who are friends, family or colleagues of the researchers who are familiar with the research and the potential health benefits of GGC. They will be randomly allocated ("drawing out of a hat" ) to three groups either A, B, or C. The allocations and the GGC administrations will be managed and performed by UNSW colleagues not associated with the trial objective to ensure the researchers are blinded to the dose levels.

The sequence of the participants' dose schedule will be determined randomly. Once Group A has completed the trial, the data will be analysed for dose response significance. If there is insufficient statistical power for any observed trends, then Group B will commence and complete the trial. The compiled Group A and Group B data will be statistical analysed and Group C will commence the trial should the statistical power still be insufficient.

Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation by drawing out of a hat
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Phase 1
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 285935 0
Name [1] 285935 0
University of New South Wales
Address [1] 285935 0
School of Biotechnology and Biomolecular Sciences (BABS)
Faculty of Science, UNSW, Sydney, NSW, 2052
Country [1] 285935 0
Primary sponsor type
University of New South Wales
c/- School of Biotechnology and Biomolecular Sciences (BABS)
Faculty of Science, UNSW, Sydney, NSW, 2052
Secondary sponsor category [1] 284756 0
Name [1] 284756 0
Address [1] 284756 0
Country [1] 284756 0

Ethics approval
Ethics application status
Ethics committee name [1] 287960 0
UNSW Human Research Ethics Committee
Ethics committee address [1] 287960 0
University of New South Wales, Sydney, NSW, 2052
Ethics committee country [1] 287960 0
Date submitted for ethics approval [1] 287960 0
Approval date [1] 287960 0
Ethics approval number [1] 287960 0

Brief summary
Gamma glutamylcysteine (GGC) is commonly found in many foods, such as garlic and whey, which are anecdotally associated with numerous health benefits. GGC can potentially be used by the body to synthesise the commonly termed “master antioxidant” glutathione, which is responsible for protecting our cells from oxidative stress and for the elimination of toxins. As we age our body’s capacity to produce sufficient glutathione progressively declines leaving us vulnerable to many age related diseases and disorders. In this study, we will investigate whether oral administered GGC can be of benefit in increasing the glutathione content in blood cells in young. mature and aged populations.
Trial website
Trial related presentations / publications
The trials initial pilot findings have been published in Redox Biology and is open access available
Zarka, M and Bridge W. Oral administration of gamma-glutamylcysteine increases intracellular glutathione levels above homeostasis in a randomised human trial pilot study. Redox Biology 2017 11 631-636.
Public notes

Principal investigator
Name 34662 0
Dr Dr Wallace Bridge
Address 34662 0
c/- School of Biotechnology and Biomolecular Sciences, Faculty of Science University of New South Wales Sydney, 2052, NSW
Country 34662 0
Phone 34662 0
+61 2 9385 1297
Fax 34662 0
Email 34662 0
Contact person for public queries
Name 17909 0
Dr Dr Wallace Bridge
Address 17909 0
c/- School of Biotechnology and Biomolecular Sciences, Faculty of Science University of New South Wales Sydney, NSW, 2052
Country 17909 0
Phone 17909 0
+61 2 9385 1297
Fax 17909 0
Email 17909 0
Contact person for scientific queries
Name 8837 0
Dr Dr Wallace Bridge
Address 8837 0
c/- School of Biotechnology and Biomolecular Sciences, Faculty of Science University of New South Wales Sydney, NSW, 2052
Country 8837 0
Phone 8837 0
+61 2 9385 1297
Fax 8837 0
Email 8837 0

No information has been provided regarding IPD availability
Summary results
No Results