Comparison
Glutathione vs L-Theanine
Side-by-side of Glutathione and L-Theanine. Every row below is pulled from the compound schema and will update as our data grows. For deeper reads, follow through to each compound page.
Glutathione
Glutathione (GSH) is the body's primary intracellular antioxidant. Oral supplementation has variable bioavailability; sublingual, liposomal, and IV forms.
L-Theanine
L-theanine is a non-protein amino acid found in tea leaves. The most-replicated nootropic; pairs with caffeine at 1:1 (100-200 mg each) for acute focus.
Effects at a glance
Glutathione
- •Body's primary intracellular antioxidant; tripeptide of glutamate, cysteine, glycine
- •Oral bioavailability poor; sublingual, liposomal, IV more reliable
- •Richie 2014 trial showed body GSH store increases at 250-1000 mg/day for 6 months
- •NAC supplementation often more cost-effective indirect strategy
- •Modest signals in NAFLD, skin aging, immune support; weak in cardiovascular
L-Theanine
- •Non-protein amino acid in tea; the most-replicated nootropic in the human RCT literature
- •Caffeine + theanine at 1:1 (100-200 mg each) is the gold-standard acute focus stack
- •Solo doses of 200-400 mg reduce subjective stress and improve sleep quality
- •Increases alpha-wave EEG activity within 30-45 minutes of 200 mg oral dose
- •Crosses blood-brain barrier; bioavailability high, half-life 60-90 minutes
- •Clean safety record; minimal interactions at supplement doses
Side-by-side
| Attribute | Glutathione | L-Theanine |
|---|---|---|
| Category | supplement | supplement |
| Also known as | GSH, L-glutathione, reduced glutathione | theanine, gamma-glutamylethylamide |
| Half-life (hr) ↗ | 0.5 | 1.5 |
| Typical dose (mg) ↗ | 500 | 200 |
| Dosing frequency | daily, often divided | as needed (with caffeine) or daily |
| Routes | oral, sublingual, intravenous | oral |
| Onset (hr) | 1 | 0.5 |
| Peak (hr) | 2 | 1 |
| Molecular weight | 307.32 | 174.2 |
| Molecular formula | C10H17N3O6S | C7H14N2O3 |
| Mechanism | Tripeptide antioxidant; substrate for glutathione peroxidase (H2O2 reduction), GST (xenobiotic conjugation), glutaredoxin (redox signaling). GSH:GSSG ratio is the central cellular redox indicator. | Crosses BBB; modulates GABA/dopamine/serotonin (modest); increases alpha-wave EEG activity; dampens stress-induced sympathetic response without sedation. |
| Legal status | OTC dietary supplement | OTC dietary supplement |
| WADA status | allowed | allowed |
| DEA / Rx | OTC supplement | OTC supplement |
| Pregnancy | Insufficient data at supplemental doses; endogenous compound is safe | Insufficient supplement-dose data; tea-source intake safe |
| CAS | 70-18-8 | 3081-61-6 |
| PubChem CID | 124886 | 439378 |
| Wikidata | Q116907 | Q909931 |
Safety profile
Glutathione
Common side effects
- mild GI upset
Contraindications
- asthma (IV / inhaled forms specifically)
- active chemotherapy without oncologist guidance
Interactions
- chemotherapy agents: theoretical interference with GSH-depletion-dependent agents(moderate)
L-Theanine
Common side effects
- mild GI upset (rare)
- headache (rare)
Contraindications
- pregnancy / lactation (insufficient data at supplement doses)
- concurrent strong GABAergics without caution
Interactions
- caffeine: synergistic for acute focus; dampens jitter without blunting alertness(minor)
- benzodiazepines / alcohol: potential additive sedation(minor)
Which Should You Take?
L-Theanine comes out ahead for most readers on the criteria we weight: 3 catalogued goals, OTC dietary supplement, oral dosing, with a Tier-A outcome catalogued. Glutathione is the right call when one of the conditionals below applies.
- → If your priority is liver function, pick Glutathione.
- → If your priority is healthspan extension, pick Glutathione.
- → If your priority is focus or working memory, pick L-Theanine.
- → If your priority is stress and HPA-axis regulation, pick L-Theanine.
Edge case: Half-lives differ materially (Glutathione ~0.5 hr vs L-Theanine ~1.5 hr). L-Theanine reaches steady state faster; Glutathione is easier to dial in if tolerability is uncertain.
Default choice: L-Theanine. Lower friction to source, a Tier-A evidence outcome catalogued, and broader goal coverage. Reach for Glutathione only if your priority sits squarely in the goals it owns above.
This verdict is generated from each compound's schema (goals, legal status, evidence outcomes, dosing route). It updates automatically as our compound data evolves; the deeper read sits on each individual compound page.
Common questions
What is the difference between Glutathione and L-Theanine?
Glutathione and L-Theanine differ in category (supplement vs supplement), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Glutathione or L-Theanine?
Glutathione half-life is 0.5 hours; L-Theanine half-life is 1.5 hours.
Can you stack Glutathione with L-Theanine?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
Go deeper