Glutathione
Your body's master antioxidant — a tiny three-part protein that shields your cells and helps clear out toxins.
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Suggested dose
100 – 200 mg
Compound profile
Glutathione scientific & efficacy data
Anti-Aging
Peptide profile
Moderate human trials
Glutathione
100 mg per injection · Once daily by mouth; IV and inhaled protocols are typically given 1–3 times per week
Molecular formula
C10H17N3O6S
- Mol. weight
- 307.33 g/mol
- CAS number
- 70-18-8
- PubChem
- 124886
- Developed · Not engineered — a natural molecule. Discovered 1888 (de Rey-Pailhade); named and characterized by F. Gowland Hopkins (1921); confirmed as a tripeptide in 1929
- F. Gowland Hopkins (characterization); first observed by Joseph de Rey-Pailhade
University of Cambridge (Hopkins)
Amino acid sequence
γ-L-glutamyl-L-cysteinyl-glycine (Glu-Cys-Gly; an unusual gamma peptide bond links the glutamate)Antioxidant defense
The core role — directly neutralizing free radicals and powering antioxidant enzymes [4]. Strongly supported by biochemistry.
Detoxification support
Tags and helps clear toxins and drug byproducts via glutathione-S-transferase [4].
Immune support
Higher oral dosing more than doubled natural killer cell activity in a 6-month trial [2].
Dosing
How much Glutathione do I take?
100 – 200 mg · 2–3 times per week · subcutaneous
100 – 200 mg
2–3 times per week
Covers all 8 documented dose levels · 6 administration routes · timing · dose-adjustment guidance.
Every documented dose level
| Phase | Dose | Frequency | Route |
|---|---|---|---|
| Ongoing, as directed | 100 mg per injection | 2–3 times per week | Subcutaneous |
| Ongoing, as directed | 200 mg per injection (up to ~600 mg per week total) | 2–3 times per week | Subcutaneous |
| Up to 6 months | 250 mg per day | Once daily | Oral |
| Up to 6 months | 1,000 mg per day | Once daily | Oral |
| 4 weeks (as studied) | 1,400 mg per infusion | 3 times per week | Intravenous |
| Up to 3 months (as studied) | 100-200 mg per dose | 3 times daily (as studied) | Intranasal |
| 2 months (as studied) | 600 mg per injection | Every other day | Intramuscular |
| 10 weeks (as studied) | 2% oxidized glutathione (GSSG) lotion | Twice daily | Topical |
Suitability
Is Glutathione right for me?
Best for everyday antioxidant and detox support & liver and immune support
Best for
Everyday antioxidant support
Raising your body's own glutathione helps mop up free radicals — the unstable molecules behind cell wear-and-tear. Six months of daily oral dosing measurably increased body stores [2].
Liver and detox support
Glutathione tags toxins and drug byproducts so your liver can clear them out through the glutathione-S-transferase pathway [4].
Immune support
In the 6-month oral trial, the higher dose more than doubled the activity of natural killer cells, a front-line immune defender [2].
Consider alternatives if
Do not use if
Use with caution if
Not sure?
Compare Glutathione with similar peptides to find the best fit for your goals.
Administration
How do I use Glutathione?
Subcutaneous injection · Intramuscular
Route
Subcutaneous injection is the most common self-administered route in practice. Clinical studies also used intravenous (IV) infusion [1] and intranasal spray [3]; intramuscular injection is used in some clinics.
Best sites
Covers reconstitution · step-by-step technique · storage.
Safety
Is Glutathione safe?
2 common side effects · 1 serious
Glutathione has a reassuring safety record in trials, but the trials are small.
In the 6-month oral trial (54 healthy adults taking 250 or 1,000 mg a day), blood glutathione rose and returned to baseline after a 1-month washout [2].
In the IV Parkinson's trial (21 people: 11 on 1,400 mg three times a week, 10 on placebo), reported adverse events were similar in the two groups and no one withdrew because of them [1].
Intranasal glutathione was tolerated over 3 months in a 30-person trial (placebo, 300 or 600 mg per day) with no substantial difference in adverse events between groups [9]; in the follow-up 45-person trial, one of the 15 people on the highest dose (200 mg three times daily) developed cardiomyopathy — a weakening of the heart muscle [10].
The clearest warning is for the inhaled form: in 8 people with mild asthma, nebulized glutathione (600 mg) dropped lung function (FEV1) 19% versus 1% after placebo, with coughing in 4 of 8 and breathlessness in 3 of 8 — the researchers attributed the airway narrowing to sulfite formation [5].
Most human studies are small pilot trials lasting weeks to months, so long-term safety at high doses is not fully mapped. The strongest safety data are for oral and short-course IV use [1][2].
Inhaled use carries a specific asthma caution: 600 mg nebulized dropped FEV1 19% (versus 1% on placebo) in 8 people with mild asthma [5], while a separate 12-person asthma study found the same 600 mg inhaled dose protected against 'fog'-challenge airway narrowing (a 6% FEV1 fall versus 20% after placebo) [11].
The two findings stand together; the first study traces the risk to sulfite formation [5].
Less common
These typically resolve with continued use or dose adjustment.
Common side effects · experienced by some users
Generally well tolerated
Across oral and IV studies, most people had no significant side effects [1][2].
Management: No action needed for most users; start low and build up.
Unpleasant smell or taste
Sulfur-containing glutathione can have a rotten-egg odor, most noticeable with inhaled or liquid forms.
Management: Use capsules or rinse the mouth; this is harmless.
Stop and seek help if
- Any wheezing, cough or chest tightness with inhaled forms
- Signs of an allergic reaction (rash, swelling, trouble breathing)
- Persistent stomach upset that does not settle with a lower dose
- Your doctor advises stopping before a procedure or new treatment
This information is educational and not medical advice. Glutathione is not an FDA-approved drug. Talk with a qualified healthcare provider before starting, especially if you have asthma, are pregnant or breastfeeding, or take other medicines.
With other peptides
- Safe:Most research peptides — No specific peptide interactions are well documented; generally considered compatible
With medications
- Caution:Chemotherapy (e.g., cisplatin) — Studied to reduce some chemo side effects, but could affect treatment — use only under oncologist guidance
- Safe:Other prescription medicines — Discuss with your doctor before combining
With supplements
- Safe:Vitamin C — Helps recycle glutathione back to its active form
- Safe:N-acetylcysteine (NAC) — Supplies cysteine the body uses to build glutathione
- Safe:Alpha-lipoic acid — Supports glutathione regeneration
- Safe:Selenium — A cofactor for glutathione peroxidase
Effectiveness
How do I know Glutathione is working?
Moderate human trials · first signs weeks 1–4
Evidence level
Moderate human trials
(Phase 1-2)
Regulatory status
Sold as a dietary supplement; not FDA-approved as a drug
IV and inhaled uses are off-label/compounded.
Onset of effects
Builds gradually — blood and tissue levels rise over weeks of steady use, while IV and inhaled forms act faster
How it works
Think of glutathione as your cells' cleanup crew.
Free radicals are like sparks that can start tiny fires of damage inside you. Glutathione throws water on those sparks. It also acts like a garbage tag — it sticks to poisons so your liver knows what to haul away. Once it has done its work, an enzyme recharges it so it can go again.
The deeper mechanism
Glutathione (GSH) works through several linked pathways. As a direct antioxidant, the thiol (-SH) group on its cysteine donates electrons to neutralize reactive oxygen species.
As a cofactor for glutathione peroxidase, it reduces hydrogen peroxide and lipid peroxides, becoming oxidized to glutathione disulfide (GSSG); glutathione reductase then regenerates GSH using NADPH, keeping a high GSH:GSSG ratio.
Through glutathione-S-transferase, GSH conjugates electrophilic toxins and drug metabolites into water-soluble thioethers for excretion. It also regulates protein function by reversible S-glutathionylation of cysteine residues, a redox-signaling switch [4].
Because intact GSH is degraded by gamma-glutamyl transpeptidase in the gut, its oral bioavailability is low; intranasal dosing has been shown to raise brain GSH measured by magnetic resonance spectroscopy [3], and intravenous dosing delivers it directly to the bloodstream [1].
What to expect
Weeks 1–4
What you might notice
- Often nothing dramatic yet
- Possibly steadier energy or well-being
What's normal
- Glutathione is building quietly in your blood and tissues
- No obvious day-to-day change is normal this early
What's next
- Keep dosing consistently — benefits build over time
Weeks 5–12
What you might notice
- Possible improvements in general well-being
- Immune measures can rise — natural killer activity more than doubled by 3 months at the higher oral dose [2]
What's normal
- Body glutathione stores continue climbing in a dose-dependent way [2]
What's next
- Consider whether to stay at your dose or adjust with your clinician
Months 4–6+
What you might notice
- Body stores reach their fuller levels — about 30–35% higher in blood at the high oral dose [2]
What's normal
- Effects plateau as stores fill; benefits fade after stopping (values returned to baseline after a 1-month washout) [2]
What's next
- Decide on continued use; remember gains reverse once you stop
Signs it's working
Not seeing results? Common reasons
- Using a plain oral form that is largely broken down in the gut — try liposomal, NAC, or clinic-administered routes
- Dose too low for your goal — the higher oral dose worked better in trials [2]
- Not enough time — body stores build over weeks to months [2]
- Expecting an immediate, obvious effect when changes are mostly internal
Key research
Clinical trials
Glutathione tested in people
94 registered studies, 17 still enrolling.
By phase
A trial spanning two phases is counted in both, so these can sum above the total. Observational studies carry no phase.
What kind of research
About 7,062 people took part in the studies that actually administered Glutathione. Observational studies analyse the records of people already taking it — nobody was given anything for the study, so they are counted separately and cannot show cause and effect.
Most recent
S-Acetyl Glutathione and Performance Recovery in Soccer
University of Thessaly
Weight Gain in Pediatric Leukemia Survivors
Washington University School of Medicine
GAIP ASD Research Study
Greater Atlanta Integrative Pediatrics
Sources: ClinicalTrials.gov, the EU Clinical Trials Information System and ISRCTN, deduplicated so a study registered twice is counted once. A study is counted when Glutathione is named as an intervention; studies that only mention it in passing are not.
Questions
Frequently asked about Glutathione
Does oral glutathione actually work, or is it destroyed in the stomach?
Both things are true. Plain glutathione is largely broken down by a gut enzyme, so little reaches your blood intact. But a careful 6-month study still found that daily oral doses of 250–1,000 mg raised the body's glutathione stores and boosted some immune cells [2]. Liposomal forms and precursors like NAC are designed to improve absorption.
Is glutathione safe?
Can glutathione help Parkinson's disease?
How long until I notice anything?
Glutathione works quietly. Body stores build over weeks, with immune changes seen by about 3 months and fuller blood levels by 6 months in studies [2]. Many people will not feel a dramatic day-to-day change.
What is the difference between glutathione and NAC?
NAC (N-acetylcysteine) is a building block your body uses to make its own glutathione. Glutathione is the finished molecule. Because NAC absorbs well by mouth, some people use it as an easier way to raise glutathione indirectly.
Ready for the protocol?
Every dosing tier, administration route, timing note, and dose-adjustment rule for Glutathione, on one page.