NR (Nicotinamide Riboside) vs Urolithin A

Mechanism

NR is converted to NMN by nicotinamide riboside kinases (NRK1/NRK2), then to NAD+ via the salvage pathway. Like NMN, elevated NAD+ activates sirtuins, PARPs, and CD38. NR has demonstrated ability to cross the blood-brain barrier and elevate brain NAD+ levels. It supports mitochondrial function, DNA repair, and circadian rhythm regulation through SIRT1-mediated deacetylation of BMAL1 and CLOCK proteins.

Standard Dosing

300-600mg daily

Timing

Morning with or without food.

Cycle Duration

ongoing

Side Effects

• Mild nausea
• Warmth/flushing (mild)
• GI upset
• Fatigue in some during initial days

Contraindications

• Active cancer (same theoretical NAD+ concern as NMN)
• Pregnancy/lactation
• Theoretical cancer concern shared with NMN

Best Stacking Partners

Mechanism

Gut metabolite of ellagitannins that activates mitophagy — selective clearance of damaged mitochondria. Improves mitochondrial function, muscle endurance, and cellular energy production. Only ~40% of population can produce it endogenously.

Contraindications

• Limited long-term safety data beyond 4 months