Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| NR (Nicotinamide Riboside) | Vitamin D3 | |
|---|---|---|
| Category | Supplements | Vitamins |
| Standard Dose | 300-600mg daily | 5000 IU daily (125 mcg) |
| Timing | Morning with or without food. | With largest fat-containing meal of the day (fat-soluble). Morning preferred. |
| Cycle Duration | ongoing | ongoing (lifelong for most people in northern latitudes) |
| Evidence Level | Moderate-Strong | strong_human |
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.
300-600mg daily
Morning with or without food.
ongoing
Vitamin D3 (cholecalciferol) is hydroxylated in the liver to 25(OH)D (calcidiol), then in the kidneys to 1,25(OH)2D (calcitriol), the active hormone. Calcitriol binds the nuclear vitamin D receptor (VDR), forming a heterodimer with RXR that regulates >1000 genes. Key actions: upregulation of intestinal calcium/phosphorus absorption (TRPV6, calbindin), modulation of innate immunity (cathelicidin LL-37 antimicrobial peptide production), suppression of adaptive immune overactivation (Th1/Th17 to Treg shift), regulation of PTH and osteocalcin for bone mineralization, and modulation of insulin secretion from beta cells.
5000 IU daily (125 mcg)
With largest fat-containing meal of the day (fat-soluble). Morning preferred.
ongoing (lifelong for most people in northern latitudes)
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