Comparison
Methylene Blue vs TB-500
Side-by-side of Methylene Blue 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.
Methylene Blue
Methylene blue as a nootropic: low-dose cognitive enhancement, mitochondrial electron cycling, brain oxygen uptake, SSRI interaction risk, typical 0.5 to 4 mg.
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
Methylene Blue
- •FDA approved for methemoglobinemia and ifosfamide-induced encephalopathy
- •Mitochondrial electron-transport support at low doses (0.5 to 4 mg/kg) via cytochrome c shuttle
- •Potent MAO-A inhibitor; serotonin syndrome risk with SSRIs, SNRIs, MAOIs, fentanyl, tramadol, St John's wort
- •Causes harmless blue-green urine and sweat coloration; useful adherence marker
- •G6PD deficiency is an absolute contraindication; can trigger massive hemolysis
- •Cognitive-enhancement evidence is preliminary, mostly preclinical and small fMRI trials
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 | Methylene Blue | TB-500 |
|---|---|---|
| Category | pharmaceutical | peptide |
| Also known as | Methylthioninium chloride, Provayblue, tetramethylthionine chloride | Thymosin Beta-4 fragment, TB4-Frag, Thymosin Beta 4 |
| Half-life (hr) ↗ | 5.5 | 2 |
| Typical dose (mg) ↗ | 70 | 2.5 |
| Dosing frequency | 1 to 3 times daily for cognitive use; single IV dose for methemoglobinemia | 2x weekly (anecdotal protocols) |
| Routes | oral, intravenous | subcutaneous, intramuscular |
| Onset (hr) | 1 | - |
| Peak (hr) | 1.5 | - |
| Molecular weight | 319.85 | 4963.4 |
| Molecular formula | C16H18ClN3S | C212H350N56O78S |
| Mechanism | Mitochondrial electron carrier at low doses (cytochrome c shuttle to complex IV) and methemoglobin reductase substrate at higher doses; potent MAO-A inhibitor across the dose range. | 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 | Prescription (injectable, FDA approved); supplement form (oral) widely available; not scheduled | Not FDA approved; research-use-only grey market; banned by WADA |
| WADA status | allowed | banned |
| DEA / Rx | Not scheduled in the US | Not FDA approved; not scheduled; research-chemical status |
| Pregnancy | Contraindicated | Insufficient data |
| CAS | 61-73-4 | 885340-08-9 |
| PubChem CID | 6099 | 62707662 |
| Wikidata | Q409021 | Q7799921 |
Safety profile
Methylene Blue
Common side effects
- blue-green urine and sweat
- skin and oral mucosa staining
- GI upset
- headache
- dizziness
Contraindications
- G6PD deficiency
- pregnancy
- concurrent serotonergic medication
- severe renal impairment
- infants under 6 months
Interactions
- SSRIs and SNRIs: serotonin syndrome, potentially fatal(major)
- MAOIs: additive MAO inhibition, serotonin syndrome risk(major)
- fentanyl, tramadol, meperidine: serotonin syndrome risk(major)
- dextromethorphan: serotonin syndrome risk(major)
- St John's wort: serotonin syndrome risk(major)
- lithium: additive serotonergic risk(major)
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?
Methylene Blue comes out ahead for most readers on the criteria we weight: 3 catalogued goals, controlled substance, 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 Methylene Blue.
- → If your priority is mitochondrial function, pick Methylene Blue.
- → If your priority is post-training recovery, pick TB-500.
- → If your priority is tendon repair, pick TB-500.
Edge case: If you cannot self-administer injections, Methylene Blue is the only oral option in this pair.
Default choice: Methylene Blue. Wider use case, 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 Methylene Blue and TB-500?
Methylene Blue and TB-500 differ in category (pharmaceutical vs peptide), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Methylene Blue or TB-500?
Methylene Blue half-life is 5.5 hours; TB-500 half-life is 2 hours.
Can you stack Methylene Blue 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.
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