Comparison
Fisetin vs TB-500
Side-by-side of Fisetin 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.
Fisetin
Fisetin is a flavonoid found in strawberries with senolytic activity in mouse models. Hickson 2019 confirmed senescent-cell clearance in human adipose tissue.
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
Fisetin
- •Flavonoid found in strawberries; most potent natural senolytic in screening assays (Yousefzadeh 2018)
- •Hickson 2019 confirmed reduced senescent-cell burden in human adipose tissue at 20 mg/kg pulsed for 2 days
- •Pulsed Mayo protocol (20 mg/kg/day x 2 days monthly) is the only dose with human biomarker evidence
- •Daily low-dose (100-500 mg) is mechanistically weaker but commonly used
- •Low oral bioavailability; with-fat dosing modestly improves absorption
- •Active cancer is a relative contraindication pending clearer polyphenol-treatment data
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 | Fisetin | TB-500 |
|---|---|---|
| Category | supplement | peptide |
| Also known as | 3,7,3',4'-tetrahydroxyflavone | Thymosin Beta-4 fragment, TB4-Frag, Thymosin Beta 4 |
| Half-life (hr) ↗ | 2 | 2 |
| Typical dose (mg) ↗ | 500 | 2.5 |
| Dosing frequency | pulsed 2 days/month (Mayo protocol) or daily continuous (empirical) | 2x weekly (anecdotal protocols) |
| Routes | oral | subcutaneous, intramuscular |
| Onset (hr) | 1 | - |
| Peak (hr) | 4 | - |
| Molecular weight | 286.24 | 4963.4 |
| Molecular formula | C15H10O6 | C212H350N56O78S |
| Mechanism | Senolytic via Bcl-2 family inhibition (Bcl-xL, Bcl-w); broad polyphenol with Nrf2 activation, mTOR inhibition at high concentrations, and antioxidant effects. | 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 data | Insufficient data |
| CAS | 528-48-3 | 885340-08-9 |
| PubChem CID | 5281614 | 62707662 |
| Wikidata | Q230614 | Q7799921 |
Safety profile
Fisetin
Common side effects
- mild GI upset
- headache (rare)
Contraindications
- active cancer (theoretical, polyphenol interactions)
- pregnancy and lactation (insufficient data)
- concurrent CYP3A4-sensitive medications
Interactions
- statins (CYP3A4 substrates): theoretical reduction in statin clearance at high fisetin doses(minor)
- warfarin: theoretical CYP-mediated interaction; monitor INR if combining(moderate)
- other senolytics (rapamycin, dasatinib + quercetin): additive senolytic effect; pairing is investigational(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?
Fisetin comes out ahead for most readers on the criteria we weight: 2 catalogued goals, OTC dietary supplement, oral dosing, with a Tier-B outcome catalogued. TB-500 is the right call when one of the conditionals below applies.
- → If your priority is healthspan extension, pick Fisetin.
- → If your priority is focus or working memory, pick Fisetin.
- → 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, Fisetin is the more accessible choice.
Default choice: Fisetin. Lower friction to source, 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 Fisetin and TB-500?
Fisetin 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, Fisetin or TB-500?
Fisetin half-life is 2 hours; TB-500 half-life is 2 hours.
Can you stack Fisetin 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