Glutathione: research protocol, dosing & reconstitution
Also known as: GSH, L-glutathione, Reduced glutathione
Quick answer
What is Glutathione?
Glutathione is the body's main antioxidant — a three-amino-acid molecule (glutamate, cysteine, glycine) made inside every cell. It is studied for oxidative stress, immune function and detoxification chemistry and, more controversially, for skin lightening. Oral and injectable forms exist; the injectable is unapproved in Canada and the US.
What Glutathione is
Glutathione (GSH) is technically a tripeptide but behaves nothing like the signalling peptides in this library: cells make it themselves in millimolar quantities, and its job is chemistry rather than signalling. The thiol group on its cysteine donates electrons to neutralise peroxides and reactive oxygen species; the oxidised form (GSSG) is then recycled back using NADPH [1].
The ratio of reduced to oxidised glutathione is one of the most-used laboratory markers of oxidative stress. That is the research question — whether supplying more of it from outside changes that balance in a living person, and by which route.
Mechanism of action
Synthesis takes two ATP-dependent steps (glutamate-cysteine ligase, then glutathione synthetase), and cysteine availability is the rate-limiting factor. Beyond scavenging, glutathione is the substrate for glutathione peroxidase, is conjugated to drugs and toxins so they can be excreted — the literal ‘detox’ role — and regulates protein thiols [1].
Whether oral glutathione survives digestion was long doubted, and the two best trials disagree. Four weeks at 500 mg twice daily produced no change in oxidative-stress biomarkers [3]; six months at 250 or 1,000 mg daily raised glutathione in red blood cells by 30–35%, with natural-killer cytotoxicity more than doubling in the high-dose group at three months [2]. Duration appears to be the difference.
The skin-lightening use rests on a different mechanism — inhibition of tyrosinase and a shift from dark eumelanin to lighter pheomelanin. A 2016 review of the evidence concludes that injectable and intravenous glutathione for lightening has no approved indication anywhere and has drawn safety warnings, with the strongest (still weak) data being for oral and topical use [4].
What researchers study Glutathione for
- Oxidative-stress and redox biology (GSH/GSSG ratio)
- Immune function — NK-cell activity and lymphocyte proliferation
- Xenobiotic conjugation and hepatic detoxification chemistry
- Melanogenesis and pigmentation (tyrosinase inhibition)
What dose of Glutathione do researchers use?
Research literature commonly references doses of Injectable protocols reference ~200–600 mg per administration; oral trials used 250–1,000 mg daily. This is not a recommendation — the table below summarizes protocols as they appear in published literature and trial designs.
| Context | Dose | Frequency | Duration |
|---|---|---|---|
| Oral RCT, 6 months [2] | 250 or 1,000 mg | Daily | 6 months |
| Oral RCT, 4 weeks [3] | 500 mg | Twice daily | 4 weeks — no biomarker change |
| Injectable community reference | 200–600 mg SC/IM | 1–3× weekly | 4–8 weeks on, 2–4 off; no controlled trials |
← Swipe to see the full table
Half-life and dosing timing
Half-life: Short — cleared from plasma within minutes; varies by route. Route referenced in research: Subcutaneous, intramuscular or intravenous (research); oral supplements exist. Plasma glutathione is cleared within minutes — cells take it apart at the membrane and rebuild it inside — so blood levels shortly after a dose say little. The trial that showed a rise in stored glutathione used daily oral dosing sustained for months [2]; the four-week trial showed nothing [3]. Duration matters more than dose frequency.
Titration: start low, go slow
None established. Community injectable protocols step from 200 mg toward 600 mg over several weeks; the oral trials used fixed doses. The only dose-related signal in the literature is that 1,000 mg/day oral outperformed 250 mg/day on immune markers [2].
Skip the Glutathione math
Enter vial size, water volume, and target dose — the free calculator returns concentration, injection volume, and exact U-100 syringe units.
How is Glutathione reconstituted?
| Vial size | BAC water | Concentration | Worked example |
|---|---|---|---|
| 600 mg | 3 mL | 200 mg/mL | 200 mg = 1.0 mL = 100 units (a full 1 mL syringe) |
| 600 mg | 6 mL | 100 mg/mL | 200 mg = 2.0 mL — needs a 3 mL syringe, not a U-100 insulin syringe |
Glutathione vialsVialThe small sealed glass container peptides are supplied in, topped with a rubber septum that a syringe needle can pass through.See glossary → are measured in milligrams, not microgramsMicrogram (mcg / µg)One millionth of a gram, or one thousandth of a milligram. Most peptide research doses are measured in micrograms.See glossary →, so the volumes are large. Add 3 mL of bacteriostatic waterBAC water (bacteriostatic water)Sterile water containing 0.9% benzyl alcohol, which suppresses bacterial growth. It is the standard diluent used to reconstitute lyophilized peptides for multi-dose research vials.See glossary → to a 600 mg vial: 600 mg ÷ 3 mL = 200 mg/mL. A 200 mg dose is 200 ÷ 200 = 1.0 mL — the entire capacity of a 1 mL insulin syringe. Reduced glutathione oxidises in solution, so vials are typically reconstitutedReconstitutionThe process of mixing a freeze-dried (lyophilized) peptide powder with bacteriostatic water to create a solution of known concentration.See glossary → close to use rather than stored for weeks.
New to the process? Read the full step-by-step reconstitution guide.
How long does reconstituted Glutathione last?
LyophilizedLyophilizedFreeze-dried. Peptides are shipped as a lyophilized powder ('puck') because the dry form is far more stable than a solution. It must be reconstituted before use in research.See glossary →: 2–8°C, protected from light. Reconstituted: refrigerate and use promptly — the reduced (active) form oxidises to GSSG in solution within days, faster with heat, light or air exposure.
What is Glutathione stacked with in research?
Referenced alongside vitamin C (which recycles oxidised glutathione) and NAD+ (the precursor of the NADPH that glutathione reductase needs) in antioxidant and longevity discussions; the combinations are mechanistically coherent but have not been studied together in controlled trials.
Side effects observed in research
Oral glutathione was well tolerated in both trials [2][3]. The safety concern is intravenous use in unregulated skin-lightening clinics, where the review literature records serious adverse events and warnings from regulators including the Philippine FDA [4]. Injectable glutathione has no approved indication for lightening or general wellness in Canada or the US and is sold as Research Use OnlyRUO (Research Use Only)A regulatory classification meaning a product is sold strictly for laboratory research and is not approved, labeled, or intended for human or veterinary use.See glossary →.
- Injection-site discomfort
- Well tolerated orally in trials
- IV use in unregulated skin-lightening clinics has drawn regulator warnings
Source in Canada
COA-documented research compounds, sourced from Canada.
RegenBioSignals →Referral partner — we may earn a commission.
Frequently asked questions
Is glutathione really a peptide?
Chemically yes — a tripeptide with an unusual gamma bond that makes it resistant to normal digestion. Functionally it is an antioxidant, not a signalling molecule, so almost nothing else in this library is a good analogy for it.
Does oral glutathione get absorbed?
The two best trials disagree, and duration is the likely reason: four weeks at 500 mg twice daily changed nothing [3], while six months at 250–1,000 mg daily raised stored glutathione by about a third [2]. Neither measured injectable forms.
Is injectable glutathione approved in Canada?
No. It has no approved indication for skin lightening, ‘detox’ or general wellness in Canada or the US, and the review literature warns specifically about IV use in cosmetic clinics [4]. Research-grade material is Research Use Only.
What does ‘detox’ mean here?
Something specific: liver enzymes attach glutathione to drugs and toxins so they become water-soluble and can be excreted [1]. It is a real biochemical pathway — not the vague marketing sense of the word — and no trial shows that supplementation accelerates it in healthy people.
Related research peptides
Thymosin Alpha-1
A 28-amino-acid peptide first isolated from the thymus, studied as an immune regulator. An approved prescription drug in some countries; Research Use Only in Canada.
Immune / GutVIP
A 28-amino-acid signalling peptide found in the gut, lungs, brain and immune system, studied for immune regulation and for relaxing airways and blood vessels. Survives about a minute in blood, so research uses inhaled or intranasal routes.
Healing & RecoveryBPC-157
A synthetic peptide fragment studied for tissue repair, tendon/ligament and gut healing in animal research.
Browse all Immune / Gut peptides or start with the beginner’s guide to research peptides.
References
- 1.Forman HJ, Zhang H, Rinna A. Glutathione: overview of its protective roles, measurement, and biosynthesis. Mol Aspects Med. 2009. PubMed ↗
- 2.Richie JP Jr, et al. Randomized controlled trial of oral glutathione supplementation on body stores of glutathione. Eur J Nutr. 2015. PubMed ↗
- 3.Allen J, Bradley RD. Effects of oral glutathione supplementation on systemic oxidative stress biomarkers in human volunteers. J Altern Complement Med. 2011. PubMed ↗
- 4.Sonthalia S, Daulatabad D, Sarkar R. Glutathione as a skin whitening agent: Facts, myths, evidence and controversies. Indian J Dermatol Venereol Leprol. 2016. PubMed ↗