Comparison
L-Theanine vs TB-500
Side-by-side of L-Theanine and TB-500. 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.
TB-500
TB-500 peptide, a 17-aa thymosin beta-4 fragment. Preclinical tendon and wound healing via actin sequestration. Typical dosage 2 to 5 mg weekly. No human RCTs.
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
TB-500
- •17-amino-acid fragment of endogenous Thymosin Beta-4, an actin-sequestering peptide
- •Preclinical models show accelerated tendon, ligament, and dermal wound healing
- •Equine veterinary use for soft-tissue injury is the most documented real-world application
- •Anecdotal human protocols use 2 to 5 mg twice weekly subcutaneously for 4 to 6 weeks
- •WADA banned under S2 (peptide hormones, growth factors) since 2018
- •No completed phase II or III human RCTs as of 2026; long-term safety unestablished
Side-by-side
| Attribute | L-Theanine | TB-500 |
|---|---|---|
| Category | supplement | peptide |
| Also known as | theanine, gamma-glutamylethylamide | Thymosin Beta-4 fragment, TB4-Frag, Thymosin Beta 4 |
| Half-life (hr) ↗ | 1.5 | 2 |
| Typical dose (mg) ↗ | 200 | 2.5 |
| Dosing frequency | as needed (with caffeine) or daily | 2x weekly (anecdotal protocols) |
| Routes | oral | subcutaneous, intramuscular |
| Onset (hr) | 0.5 | - |
| Peak (hr) | 1 | - |
| Molecular weight | 174.2 | 4963.4 |
| Molecular formula | C7H14N2O3 | C212H350N56O78S |
| Mechanism | Crosses BBB; modulates GABA/dopamine/serotonin (modest); increases alpha-wave EEG activity; dampens stress-induced sympathetic response without sedation. | Sequesters G-actin monomers, modulates cell migration and angiogenesis, and upregulates VEGF and myosin transcription. Promotes endothelial differentiation and stem-cell migration to injury sites in preclinical models. |
| Legal status | OTC dietary supplement | Not FDA approved; research-use-only grey market; banned by WADA |
| WADA status | allowed | banned |
| DEA / Rx | OTC supplement | Not FDA approved; not scheduled; research-chemical status |
| Pregnancy | Insufficient supplement-dose data; tea-source intake safe | Insufficient data |
| CAS | 3081-61-6 | 885340-08-9 |
| PubChem CID | 439378 | 62707662 |
| Wikidata | Q909931 | Q7799921 |
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)
TB-500
Common side effects
- injection-site irritation
- fatigue (anecdotal)
- lethargy in early dosing (anecdotal)
Contraindications
- pregnancy
- active malignancy (theoretical angiogenic concern)
- no established human safety profile
Interactions
- BPC-157: Frequently co-administered in anecdotal healing protocols; no controlled interaction data(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. TB-500 is the right call when one of the conditionals below applies.
- → 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 post-training recovery, pick TB-500.
- → If your priority is tendon repair, pick TB-500.
Edge case: If you want to avoid research-only / gray-market sourcing, L-Theanine is the more accessible choice.
Default choice: L-Theanine. Lower friction to source, a Tier-A evidence outcome catalogued, and broader goal coverage. Reach for TB-500 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 L-Theanine and TB-500?
L-Theanine and TB-500 differ in category (supplement vs peptide), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, L-Theanine or TB-500?
L-Theanine half-life is 1.5 hours; TB-500 half-life is 2 hours.
Can you stack L-Theanine with TB-500?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
Go deeper