NAD+ — NAD+ precursor / sirtuin activator / PARP substrate

NAD+ supplementation is the most debated longevity intervention due to its 'upstream' metabolic role. The key clinical choice is between IV NAD+, oral NR, and oral NMN. IV NAD+ provides the fastest elevation and is preferred in recovery/addiction settings but requires 2-4 hours to manage infusion-related side effects (chest pressure, flushing). Oral NR (Nicotinamide Riboside) has the most human safety data and GRAS status. Oral NMN (Nicotinamide Mononucleotide) is favored by some researchers for a more direct conversion to NAD+ and potential specific transporters. Methylation depletion is a genuine clinical concern — if high-dose precursors are used long-term, adding a methyl donor (TMG 500-1000mg or methyl-B12) is prudent to avoid homocysteine elevation. The cancer risk remains purely theoretical and preclinical; no human trial has demonstrated tumor promotion, but caution is warranted in patients with active malignancy.

نظرة عامة

هذه الصفحة جزء من مكتبة المركّبات المُصنَّفة بالأدلة في Hormonaly. جميع الادعاءات السريرية مرتبطة بمصادر علمية مُحكَّمة عبر خط أنابيب التحقق المزدوج للاستشهادات.

فئة المركّب

NAD+ precursor / sirtuin activator / PARP substrate

آلية العمل

NAD+ (nicotinamide adenine dinucleotide) is an essential coenzyme in all living cells with two primary roles: (1) Electron carrier in metabolic redox reactions (glycolysis, TCA cycle, oxidative phosphorylation — as NAD+/NADH pair); (2) Substrate for sirtuins (SIRT1-7), PARPs, and CD38 — enzymes that regulate DNA repair, epigenetic modification, circadian rhythm, inflammation, and mitochondrial biogenesis. NAD+ levels decline ~50% between age 40-60 via: decreased biosynthesis, increased PARP activity (DNA damage), and increased CD38 expression. NMN and NR are the two commercially viable oral precursors: NR → NMN → NAD+ (intracellular synthesis via Nampt enzyme). NMN may take a more direct route via a recently discovered intestinal transporter (Slc12a8). Key effectors: SIRT1 activates PGC-1α (mitochondrial biogenesis), FOXO3a (stress resistance), p53 (DNA repair); SIRT3 protects mitochondrial integrity; SIRT6 repairs DNA double-strand breaks. IV NAD+ (NAD+ direct infusion, not precursor) achieves higher and faster plasma levels than oral precursors.

الوضع التنظيمي

Dietary supplements (NMN status currently in flux with FDA — FDA previously determined NMN is an investigational drug, not a supplement, but enforcement is stayed); NR is FDA GRAS (Generally Recognized As Safe)

مستوى الأدلة

Moderate — High for metabolic redox roles; Moderate for oral supplementation efficacy (extensive animal data; multiple small human RCTs showing NR/NMN increases NAD+ levels; limited data on hard clinical endpoints in humans); B-grade