Nicotinamide riboside (NR)

Tier 3 — weak evidence · NAD+ · Aging · Cellular energy

A precursor to NAD+ that successfully raises blood NAD+ levels in humans. Multiple trials confirm NR supplementation at 300 to 1,000 mg per day significantly increases NAD+ within 2 weeks. However, like NMN, no meaningful clinical health improvements have been demonstrated yet despite raised NAD+. The gap between biomarker changes and actual health benefits remains the key unanswered question.

Dose: 300–1,000 mg/day; successfully raises NAD+ but no clinical health benefits demonstrated yet