Not medical advice. I am a software engineer, not a physician. This page documents my own protocol and the research I read while building it. Talk to a qualified clinician before changing your supplementation, diet or any treatment. Lab reference ranges quoted here vary by laboratory and by individual.
Affiliate disclosure: the iHerb links on this page carry a referral code and pay me a commission if you buy. It does not change your price, and I do not link anything I do not use myself.
NAD+ (Nicotinamide Adenine Dinucleotide) is arguably the most important coenzyme in human biology. It is essential for cellular energy production (mitochondrial electron transport), DNA repair (PARP enzymes), epigenetic regulation (sirtuin enzymes), and cellular signaling. NAD+ levels decline by approximately 50% between ages 40 and 60, contributing to mitochondrial dysfunction, accumulated DNA damage, inflammation, and the physiological hallmarks of aging. Nicotinamide Riboside (NR) is a form of vitamin B3 that serves as a direct NAD+ precursor, following the pathway: NR → NMN → NAD+.
NR vs. NMN: Both are NAD+ precursors, but through different entry points. NR is phosphorylated intracellularly by NR kinases (NRK1/NRK2) to become NMN, which is then converted to NAD+. NMN, being larger, must be dephosphorylated to NR before cellular uptake (via the CD73 transporter), or use the recently discovered SLC12A8 transporter. The key advantage of Tru Niagen (NR): it is the first NAD+ precursor to have completed multiple human randomized controlled trials demonstrating both safety and significant NAD+ elevation.
NR enters cells via equilibrative nucleoside transporters and is phosphorylated by NR kinases (NRK1/NRK2) to NMN, which is then adenylated to NAD+ by NMNAT enzymes. This Preiss-Handler salvage pathway is the most efficient route to raise cellular NAD+ levels.
| Parameter | Detail |
|---|---|
| Product | Tru Niagen (Nicotinamide Riboside Chloride) 300 mg, 90 Vegetarian Capsules |
| Dose | 300 mg x 3/day (breakfast + lunch + dinner) = 900 mg/day total |
| Timing | Divided with meals for sustained NAD+ elevation throughout the day |
| Rationale | ChromaDex patented NIAGEN form. 900 mg/day based on dose-response data showing robust NAD+ elevation. Split dosing maintains more consistent blood NR levels than a single large dose. |
| Duration | 2-4 weeks for measurable NAD+ elevation; ongoing for sustained longevity benefits |
Martens, C. R., et al. (2018). Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults. Nat Commun, 9(1), 1286. PubMed 29992272
Conze, D., et al. (2019). Safety and metabolism of long-term administration of NIAGEN (nicotinamide riboside chloride) in a randomized, double-blind, placebo-controlled clinical trial. Sci Rep, 9(1), 9772. PubMed 30231218
Covarrubias, A. J., et al. (2021). NAD+ metabolism and its roles in cellular processes during ageing. Nat Rev Mol Cell Biol, 22(2), 119-141. PubMed 33888596
A 2025 randomized controlled trial published in eClinicalMedicine (The Lancet) examined NR supplementation for long-COVID symptoms. Although overall group differences were limited, many participants showed encouraging improvements after 10+ weeks of NR, including boosts in NAD+ levels and potential improvements in fatigue, sleep, and mood. A landmark 2025 double-blind trial in Werner Syndrome (premature aging) patients revealed that NR safely boosted NAD+ levels while improving cardiovascular health, reducing skin ulcers, and protecting kidney function. A 2025 updated review comparing NMN and NR found both raise NAD+ levels during aging, though current evidence does not support either for preserving skeletal muscle mass and function in adults over 60.
| Test | Why It Matters | Details |
|---|---|---|
| CRP (C-Reactive Protein) | NAD+ elevation activates SIRT1, which deacetylates NF-kB and reduces inflammatory cytokine production. Declining CRP confirms the anti-inflammatory effect of NR supplementation. | Lab Tests |
| HbA1c | NAD+ is central to glucose metabolism and insulin sensitivity. Improved NAD+ status may favorably affect glycemic control, trackable via HbA1c. | Lab Tests |
Tru Niagen Nicotinamide Riboside 300 mg (90 Vegetarian Capsules) — $100.00
ChromaDex patented NIAGEN form — the only NR with completed human RCTs. Each capsule provides 300 mg NR chloride. Third-party tested, FDA GRAS-designated.
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April 2026 Systematic Review: A PRISMA-guided review in Ageing Research Reviews confirmed that oral NR/NMN reliably raises NAD-related biomarkers in humans, but clinical effects on metabolic, vascular, and performance outcomes remain mixed. Longer, adequately powered RCTs with clinically meaningful endpoints are still needed. Source