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BiologicalX

Comparison

Fisetin vs Urolithin A

Side-by-side of Fisetin and Urolithin A. 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.

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

Urolithin A

  • Gut-microbiome-derived metabolite of pomegranate and walnut ellagitannins
  • Roughly 40% of adults are 'urolithin producers' from dietary intake; ~60% are non-producers
  • Ryu 2016 (Nature Medicine) reported lifespan extension in C. elegans and muscle benefits in aged rodents
  • Andreux 2019 first-in-human trial (n=60) established safety and mitochondrial gene-expression upregulation
  • Singh 2022 (n=66, 4 months, 1000 mg/day) reported improved muscle endurance in older adults
  • Most human trial portfolio is Amazentis-funded; independent replication is thin

Side-by-side

Attribute Fisetin Urolithin A
Category supplement supplement
Also known as 3,7,3',4'-tetrahydroxyflavone UA, Mitopure, ellagitannin metabolite
Half-life (hr) 2 17
Typical dose (mg) 500 500
Dosing frequency pulsed 2 days/month (Mayo protocol) or daily continuous (empirical) daily, morning with food
Routes oral oral
Onset (hr) 1 2
Peak (hr) 4 4
Molecular weight 286.24 228.2
Molecular formula C15H10O6 C13H8O4
Mechanism Senolytic via Bcl-2 family inhibition (Bcl-xL, Bcl-w); broad polyphenol with Nrf2 activation, mTOR inhibition at high concentrations, and antioxidant effects. Induces mitophagy via potentiation of PINK1/Parkin signaling, leading to selective degradation of damaged mitochondria. Secondary anti-inflammatory effects via NF-kB modulation.
Legal status OTC dietary supplement OTC dietary supplement (US GRAS 2018; EFSA Novel Food 2021)
WADA status allowed allowed
DEA / Rx OTC supplement OTC supplement (not scheduled)
Pregnancy Insufficient data Insufficient data; not routinely recommended
CAS 528-48-3 1143-70-0
PubChem CID 5281614 5488186
Wikidata Q230614 Q27101321

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)

Urolithin A

Common side effects

  • mild GI upset (rare)
  • soft stools (rare)

Contraindications

  • pregnancy and lactation (insufficient data)
  • active chemotherapy (consult oncology)

Interactions

  • chemotherapy agents: theoretical interaction with mitochondrial-targeting agents; consult oncologist(moderate)

Which Should You Take?

Urolithin A 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. Fisetin is the right call when one of the conditionals below applies.

  • If your priority is focus or working memory, pick Fisetin.
  • If your priority is muscle hypertrophy, pick Urolithin A.
  • If your priority is mitochondrial function, pick Urolithin A.

Edge case: Half-lives differ materially (Fisetin ~2 hr vs Urolithin A ~17 hr). Urolithin A reaches steady state faster; Fisetin is easier to dial in if tolerability is uncertain.

Default choice: Urolithin A. Lower friction to source, a Tier-A evidence outcome catalogued, and broader goal coverage. Reach for Fisetin 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 Urolithin A?

Fisetin and Urolithin A 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, Fisetin or Urolithin A?

Fisetin half-life is 2 hours; Urolithin A half-life is 17 hours.

Can you stack Fisetin with Urolithin A?

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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