Comparison
L-Theanine vs TUDCA
Side-by-side of L-Theanine and TUDCA. 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.
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.
TUDCA
TUDCA is the taurine-conjugated form of ursodeoxycholic acid, a bile-acid molecule with replicated effects on liver function, ER stress, and bile flow.
Effects at a glance
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
TUDCA
- •Bile-acid molecule (taurine-conjugated UDCA) with chemical chaperone activity at the endoplasmic reticulum
- •Established pharmaceutical use for cholestasis and primary biliary cholangitis at 500-750 mg/day
- •Reduces ER stress and stabilizes misfolded proteins; the mechanistic basis for emerging ALS / retinal applications
- •Modest improvements in NAFLD markers and insulin sensitivity at 500-1,750 mg/day in small trials
- •Mitochondrial protection signal in animal models drives the longevity-supplement positioning
- •Generally well-tolerated; mild GI effects are the main dose-dependent issue
Side-by-side
| Attribute | L-Theanine | TUDCA |
|---|---|---|
| Category | supplement | supplement |
| Also known as | theanine, gamma-glutamylethylamide | tauroursodeoxycholic acid, taurine-conjugated UDCA |
| Half-life (hr) ↗ | 1.5 | 4 |
| Typical dose (mg) ↗ | 200 | 500 |
| Dosing frequency | as needed (with caffeine) or daily | daily, divided into 2 doses with food |
| Routes | oral | oral |
| Onset (hr) | 0.5 | 1 |
| Peak (hr) | 1 | 2 |
| Molecular weight | 174.2 | 499.7 |
| Molecular formula | C7H14N2O3 | C26H45NO6S |
| Mechanism | Crosses BBB; modulates GABA/dopamine/serotonin (modest); increases alpha-wave EEG activity; dampens stress-induced sympathetic response without sedation. | Bile-acid signaling via FXR/TGR5 receptors; chemical chaperone reducing ER stress and unfolded protein response; mitochondrial protection through reduced outer-membrane permeabilization. |
| Legal status | OTC dietary supplement | OTC dietary supplement (US); pharmaceutical in Italy and several Asian countries |
| WADA status | allowed | allowed |
| DEA / Rx | OTC supplement | OTC supplement |
| Pregnancy | Insufficient supplement-dose data; tea-source intake safe | Insufficient data for supplement use; UDCA used in cholestasis of pregnancy |
| CAS | 3081-61-6 | 14605-22-2 |
| PubChem CID | 439378 | 9848818 |
| Wikidata | Q909931 | Q418751 |
Safety profile
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)
TUDCA
Common side effects
- mild GI upset
- diarrhea (dose-dependent)
- constipation (rare)
- nausea
Contraindications
- complete biliary obstruction
- pregnancy / lactation (insufficient supplement-dose data)
- active GI disease without medical supervision
Interactions
- cyclosporine, oral contraceptives, fat-soluble vitamins: modest absorption changes via altered bile-acid pool(minor)
- phenylbutyrate: synergistic for ALS use (Relyvrio combination); consult clinician(moderate)
Which Should You Take?
L-Theanine and TUDCA score evenly on the criteria we weight (goal breadth, legal accessibility, evidence depth). The conditionals below should drive the decision more than any aggregate score.
- → If your priority is focus or working memory, pick L-Theanine.
- → If your priority is stress and HPA-axis regulation, pick L-Theanine.
- → If your priority is liver function, pick TUDCA.
- → If your priority is healthspan extension, pick TUDCA.
Default choice: either is defensible. L-Theanine edges out on goal breadth + legal accessibility; TUDCA is the right call if your priority sits in the goals listed 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 L-Theanine and TUDCA?
L-Theanine and TUDCA 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, L-Theanine or TUDCA?
L-Theanine half-life is 1.5 hours; TUDCA half-life is 4 hours.
Can you stack L-Theanine with TUDCA?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
Go deeper