Urolithin A
TL;DR
Gut-derived postbiotic metabolite (from ellagitannins in pomegranate, walnuts, berries). Most clinically validated mitophagy inducer available. ~60% of people cannot produce therapeutic UA from food — direct supplementation bypasses the microbiome bottleneck. ATLAS RCT: +12% hamstring peak torque (500 mg) and +10.2% VO2max (1000 mg) in untrained middle-aged adults without exercise. MitoImmune 2025 (Nature Aging): first proof of immune rejuvenation in humans via mitophagy in T-cells. 500–1000 mg/day continuous. Primary stacks: NMN NAD+ (engine maintenance + fuel), Rapamycin (broader autophagy + targeted mitophagy), Spermidine.
Key Facts
| Status | OTC (Mitopure, pharmaceutical-grade) · GRAS-equivalent across all human trials |
| Class | Postbiotic metabolite / urolithin / gut-derived polyphenol metabolite |
| Mechanism | PINK1/Parkin Mitophagy induction (primary); AMPK activation; mTORC1 inhibition; PGC-1α upregulation; direct SERCA agonism (2025) |
| Dosing | 500 mg/day (strength) or 1000 mg/day (endurance/anti-aging); once daily; food-independent; continuous |
| Key risk | Mild GI effects only; zero serious adverse events across all trials |
| Critical note | ~60% cannot reach therapeutic UA levels from food; use Mitopure (HPLC-standardized) — generic supplements can deviate ±100% |
| Evidence | ATLAS · MOTIVATION · MitoImmune/Nature Aging 2025 · 25+ Amazentis RCTs · CLARITY brain aging trial launched 2025 |
Why It Matters for Vitals
Vitals hook — ATLAS trial VO2max + hamstring torque without exercise:
- ATLAS trial (n=66, untrained middle-aged adults): 500 mg UA → +12.0% hamstring peak torque; 1000 mg UA → +10.2% VO2max, +33.4 m in 6-min walk distance
- These improvements occurred without concurrent exercise — pure mitochondrial restoration effect
- For Vitals users: UA is a wearable-agnostic ergogenic aid; expect possible HRV and cardiorespiratory improvements over 8–16 weeks
- 500 mg = strength signal (hamstring torque); 1000 mg = endurance signal (VO2max, walk distance)
- MitoImmune 2025 (Nature Aging): first human proof of immune rejuvenation via mitophagy in T-cells — broader relevance for recovery and inflammation biometrics
The Population Conversion Problem
Conversion: Ellagitannins → Ellagic acid → (gut bacteria: Gordonibacter + Enterocloster + Bifidobacterium) → Urolithin A.
| Metabotype | Population | Output |
|---|---|---|
| UM-A | ~55% adults | Urolithin A only — considered protective |
| UM-B | ~45% adults | UA + Iso-UA + Urolithin B — higher dysbiosis risk |
| UM-0 | ~10% globally | Zero urolithin production — complete lack of required bacteria |
Even UM-A individuals often fail to reach therapeutic levels from food: in a 100-person crossover trial, only 12% had detectable circulating UA at baseline, and only 40% reached therapeutic threshold (>100 ng/mL) after pomegranate juice challenge. Direct supplementation guarantees uniform delivery regardless of microbiome.
Pharmacokinetics
- Absorbed in small intestine → Phase II liver metabolism → circulates as UA-glucuronide + UA-sulfate
- 500 mg Mitopure = 6× AUC vs. 8 oz standardized pomegranate juice
- Cmax (parent): 4–7 nM; Cmax (UA-glucuronide): 1500–3000 nM (massive reservoir)
- Tmax: ~6 hours; food: no impact — flexible timing
Mechanism of Action
1. Mitophagy — PINK1/Parkin Pathway (Primary)
Damaged mitochondria lose membrane potential → PINK1 fails to import → accumulates on outer membrane → recruits Parkin E3 ligase → LC3 docking → lysosomal fusion → mitochondrial destruction. Clears: excess ROS generation, mitochondrial DNA leakage (ccf-mtDNA triggers massive inflammation).
2. AMPK Activation + mTORC1 Inhibition
AMPK → ↑ fatty acid oxidation, ↑ GLUT4 translocation, ↑ glucose uptake. mTORC1 inhibition → shifts cell from anabolic exhaustion to repair mode. PGC-1α upregulation → replaces cleared mitochondria via biogenesis. SIRT1 activation + NAD+ restoration → newly synthesized mitochondria run maximally efficiently.
3. SERCA Agonism (Novel 2025 — Yonsei University)
Direct physical agonist of SERCA (sarcoplasmic/ER Ca²⁺-ATPase) — proven via Cellular Thermal Shift Assay + LC-MS/MS. Regulates calcium homeostasis in MAMs (Mitochondria-Associated ER Membranes). In fatty liver disease + palmitic acid stress: abrogates ER stress, prevents hepatocyte apoptosis. SERCA knockdown → complete loss of UA cytoprotection (confirmed essential mechanism).
4. Anti-Inflammatory
Inhibits NF-κB + Akt/MAPK upstream. ↓ IL-6, TNF-α, IL-1β; ↑ IL-10, TGF-β1. Gut barrier: ↑ MUC2 mucin via Nrf2 + AhR activation (Kyoto University). Reduces gut permeability → blocks LPS translocation → reduces systemic endotoxemia.
Clinical Trial Data
ATLAS (NCT03464500) — Middle-aged 40–64, overweight, untrained, 4 months, n=66
| Endpoint | Placebo | 500 mg UA | 1000 mg UA |
|---|---|---|---|
| Hamstring Peak Torque | baseline | +12.0% (p≤0.05) | +9.8% (p≤0.05) |
| VO2 Peak | baseline | +1.6% | +10.2% (p≤0.05) |
| 6-Min Walk Distance | baseline | −0.2 m | +33.4 m / +7.0% |
500 mg = strength. 1000 mg = endurance + aerobic + walk distance. No exercise required — pure mitochondrial restoration effect.
MOTIVATION (NCT03283462) — Elderly 65–90, 4 months, 1000 mg/day
Hand muscle (FDI): UA group +95.3 contractions vs placebo +11.6 at 2 months. Leg muscle (tibialis anterior): UA +41.4 vs placebo +5.7. Zero serious adverse events.
MitoImmune — 2025 (Nature Aging, DOI: 10.1038/s43587-025-00996-x)
4-week RCT, Goethe University. First human proof of immune rejuvenation via mitophagy. ↑ naive CD8+ T-cells; ↓ T-cell exhaustion markers. Ex vivo: UA-group immune cells had vastly superior E. coli clearance capacity. Mechanism: mitophagy in aging immune cells → biogenesis → clean energy metabolism.
ENTER (NCT06274749) — Ongoing
Metabolic syndrome + glycemic control (≥55 years). Hypothesis: enhanced mitochondrial efficiency → ↑ ATP in pancreatic beta cells → ↑ early-phase insulin secretion + incretin production → ↓ blood glucose.
CLARITY (NCT07060898) — Launched late 2025
Largest ever trial on UA and brain aging. Assessing UA impact on cognitive decline and brain aging biomarkers.
Urolithin A vs Urolithin B
| Property | Urolithin A | Urolithin B |
|---|---|---|
| Primary role | Mitophagy, metabolic homeostasis, anti-aging | Muscle anabolism, hypertrophy, anti-atrophy |
| mTORC1 | Inhibits → repair mode | Activates → protein synthesis |
| Androgen receptor | No interaction | AR agonist in vitro |
| Best use | Longevity, cognitive, cardiovascular, immune | Sarcopenia, cachexia, post-cancer muscle wasting |
Key Stacks
UA + NMN NAD+
NMN = “fuel” (NAD+ for SIRT1/mitochondrial respiration). UA = “engine maintenance” (clears broken mitochondria, drives biogenesis). Combined: UA ensures clean mitochondrial pool; NMN maximizes oxidative capacity of that pool. Mechanistically complementary, not redundant.
UA + Rapamycin — Broad + Targeted Autophagy
Rapamycin: broad macro-autophagy via mTORC1 inhibition (clears protein aggregates, damaged organelles). UA: targeted Mitophagy via PINK1/Parkin (clears damaged mitochondria specifically). Combined: clears entire cellular environment — protein debris AND mitochondrial debris. Especially relevant for neurodegeneration (amyloid-beta + tau aggregation + mitochondrial failure).
UA + Spermidine
Spermidine: macro-autophagy via AMPK/SIRT1. UA: Mitophagy (complementary, non-overlapping; Cambridge Nutrition Research Reviews 2025 confirmed distinct roles). Synergistic but distinct mechanisms.
UA + Exercise
UA delays muscular fatigue by ↑ respiratory chain complex activity + ↑ β-oxidation. Suppresses exercise-induced pro-inflammatory cytokines → accelerated recovery. Stack: UA as ergogenic base + exercise for synergistic mitochondrial adaptation.
Links
- Mitophagy — shared mechanism with Rapamycin
- NMN NAD+ — engine maintenance + fuel pairing
- Rapamycin — broad autophagy + mitophagy pair
- GLP-1 GIP Glucagon — ecnoglutide discussed there for comparison
- Peptides MOC — peptide/compound hub index