Overview
A tripeptide antioxidant synthesised in every cell, central to redox balance and detoxification. It is one of the most extensively characterised endogenous peptides in biochemistry.
Mechanism of Action
Glutathione is composed of glutamate, cysteine and glycine, with an unusual gamma peptide bond that resists standard peptidase degradation.
It functions as the principal intracellular antioxidant, donating electrons to neutralise reactive oxygen species via glutathione peroxidase.
In phase II hepatic detoxification, glutathione S-transferases conjugate glutathione to electrophilic compounds, increasing water solubility for excretion.
The ratio of reduced (GSH) to oxidised (GSSG) glutathione is used across the literature as a marker of cellular oxidative status.
Areas Being Studied
- Oxidative stress and redox biology
- Hepatic detoxification
- Skin pigmentation research
- Immune cell function
Listing a research area does not imply efficacy, approval, or suitability for any use.
Research Summary
- Depletion of glutathione is a well-documented feature in a range of disease states and in ageing, which underpins interest in restoring levels.
- Oral glutathione bioavailability has been debated in the literature because of gastrointestinal degradation; studies of liposomal and sublingual formulations report improved marker responses.
- Trials of intravenous and inhaled glutathione have been published in specific clinical research contexts.
- Dermatology research on glutathione and skin pigmentation has produced mixed published results and is frequently cited in cosmetic literature.
Potential Adverse Effects Reported in Research
- Generally reported as well tolerated in published studies at studied doses.
- Reports of transient lightening of skin tone appear in dermatology literature.
- Rare hypersensitivity and, with inhaled administration, bronchoconstriction have been reported.
- Injection-site reactions are the most common practical observation.
Reconstitution Basics
Supplied as lyophilised powder in higher milligram amounts than most peptides. Solutions are sensitive to oxidation once prepared.
Bacteriostatic water
Sterile water containing roughly 0.9% benzyl alcohol as a preservative, which inhibits bacterial growth in multi-access vials.
Sterile technique
Laboratory documentation describes disinfecting the stopper, using a fresh sterile needle for each access, and avoiding contact with non-sterile surfaces.
After reconstitution
Solutions are refrigerated, protected from light, and not subjected to repeated freeze–thaw cycles.
This section is educational background on laboratory handling. It is not an instruction or protocol.
Open the reconstitution calculator →Dosing & Reconstitution Guide
Glutathione is administered as a reduced (GSH) solution and is notably oxidation- and light-sensitive; prepared solutions are used quickly in published protocols.
Protocol overview
- Very short plasma half-life explains why intermittent sessions rather than continuous schedules are used.
- Solutions oxidise readily; discolouration is treated as loss of the reduced form.
- IV and IM routes both appear in the literature; oral bioavailability is poor.
Dosing protocol — standard titration
| Phase | Reported dose | Notes |
|---|---|---|
| Session 1 | Low end of the cited rangeObservation of tolerability. | Observation of tolerability. |
| Sessions 2–4 | Cited range, 1–2× weeklyMost protocols are weekly. | Most protocols are weekly. |
| Maintenance | Weekly or fortnightlyStudies rarely extend past several weeks. | Studies rarely extend past several weeks. |
Dosing protocol — gradual titration
| Phase | Reported dose | Notes |
|---|---|---|
| Weeks 1–2 | Low end, once weeklyConservative entry. | Conservative entry. |
| Weeks 3–8 | Cited range, once weeklySteady schedule. | Steady schedule. |
| Week 9+ | ReassessLong-term parenteral data is limited. | Long-term parenteral data is limited. |
Schedules summarise what appears in published studies, trial protocols or manufacturer documentation. They are reference material, not a recommendation.
Where to Buy Compounds & Supplies
External link. PepDex does not sell products and does not endorse any supplier.
Supplies needed
Lyophilised peptide vial
Sealed vial with an intact stopper and a legible mass label (mg or mcg).
Bacteriostatic water
Sterile water with ~0.9% benzyl alcohol, used where a vial will be accessed more than once. Sterile water for injection is used for single-access work.
Reconstitution syringe
A 1–3 mL syringe with a larger-gauge needle for drawing and transferring solvent.
Insulin syringe (U-100)
Fine-gauge syringe graduated in units; 100 units = 1 mL. Used for accurate small-volume measurement.
Alcohol prep pads
70% isopropyl swabs for disinfecting both vial stoppers before every access.
Sharps container
Rigid, puncture-resistant container for single-use needle disposal.
Refrigeration and light protection
2–8 °C storage plus an opaque box or the original carton for reconstituted vials.
Labels
Date of reconstitution, resulting concentration and compound name on every vial.
Reconstitution steps
- 01
Bring the vial to room temperature
Lyophilised powder is allowed to equilibrate out of the refrigerator before the stopper is pierced, which reduces condensation inside the vial.
- 02
Disinfect both stoppers
The peptide vial and the bacteriostatic water vial are each swabbed with 70% isopropyl alcohol and allowed to air dry.
- 03
Draw the calculated solvent volume
Solvent volume is chosen to produce a convenient concentration — the reconstitution calculator converts vial mass and solvent volume into concentration and syringe units.
- 04
Add the solvent slowly down the vial wall
The stream is directed against the glass rather than onto the powder cake. Peptides are shear-sensitive and direct jetting is avoided.
- 05
Dissolve without shaking
The vial is left to stand, then gently swirled or rolled. Shaking introduces foam and mechanical stress that can denature peptide chains.
- 06
Inspect the solution
Documentation describes checking for a clear, particle-free solution. Cloudiness, visible particulate or discolouration is treated as a failed preparation.
- 07
Label and refrigerate
The vial is labelled with compound, concentration and date, then stored at 2–8 °C protected from light.
Storage instructions
- Before reconstitution: sealed vials refrigerated and kept in the original carton; glutathione is particularly light-sensitive.
- After reconstitution: refrigerated at 2–8 °C and used quickly — many sources cite days rather than weeks because of oxidation.
- Protection from light: opaque storage is treated as mandatory, not optional.
- Any yellowing or clouding indicates oxidation and the preparation is discarded.
- Freeze–thaw cycling is avoided entirely.
Half-Life
~10 minutes (plasma, IV)
Plasma clearance is rapid; intracellular turnover rather than plasma half-life is the meaningful research measure.
Storage
- Before reconstitution
- Powder kept cold, dry and sealed; highly sensitive to moisture.
- After reconstitution
- Refrigerated and used promptly; oxidation degrades the reduced form.
- Light protection
- Protected from light and air exposure.
- Shelf-life considerations
- Notably shorter than most peptides once in solution.
Frequently Asked Questions
References
- Glutathione: overview of its protective roles, measurement, and biosynthesis
Molecular Aspects of Medicine
- Glutathione metabolism and its implications for health
The Journal of Nutrition
Related peptides
NAD+
A coenzyme present in every living cell and central to energy metabolism and DNA repair. Although not a peptide, NAD+ appears throughout longevity research and is commonly catalogued alongside research peptides.
GHK-Cu
A naturally occurring copper-binding tripeptide found in human plasma. It is among the best characterised peptides in dermatological and wound-healing research.
KPV
A tripeptide corresponding to the C-terminal sequence of alpha-melanocyte-stimulating hormone. It is studied for anti-inflammatory activity without the pigmentation effects associated with the parent hormone.
Educational reference only. Figures are compiled from published research literature. PepDex does not provide medical advice, dosing recommendations, or instructions for use.