NAD+ (direct oral supplement)

Tier 3 — weak evidence · Bioavailability problem · Precursors preferred · NMN better · Longevity

Nicotinamide adenine dinucleotide sold as a direct oral supplement for longevity and energy. Critical problem: oral NAD+ is degraded to nicotinamide by gut enzymes before absorption, meaning the body receives the same compound as taking inexpensive niacinamide. Pharmacokinetic studies confirm that oral NAD+ raises plasma NAD no better than equivalent doses of nicotinamide, while costing 10–20× more. In contrast, NMN and NR are proven precursors that directly enter the biosynthetic pathway and raise intracellular NAD+ by 40–90% in RCTs. Intravenous NAD+ bypasses oral degradation and is a…

Dose: Not recommended as standalone supplement — use NMN (250–500 mg/day) or NR (250–300 mg/day) instead; niacinamide 500 mg/day is a cost-effective alternative