NR (Nicotinamide Riboside)

Robust clinical evidence: studies by Martens (2018, Nature Communications), Trammell (2016, Nature Communications), and Conze (2019) confirm that oral NR (250-1,000 mg/day for 6-12 weeks) consistently raises NAD+ in blood by 50-150% without relevant adverse effects.

Comparative advantages vs NMN: Regulatory approval: EU Novel Food, FDA GRAS — clearly legal in supplementation. Clinical evidence: more completed studies, with well-characterised dosing, safety, and efficacy. Stability: more stable at room temperature than NMN. Cost: typically more economical per equivalent NAD+-raising dose.

Documented clinical results: increased plasma and muscle NAD+, reduced systolic blood pressure in pre-hypertensives, improved insulin sensitivity in obese adults, improved muscle mitochondrial function, reduced inflammatory markers (CRP, IL-6, IL-8) in those over 65, and possible cognitive improvement in preliminary studies of Parkinson's and early Alzheimer's.

Limitations: although NR raises systemic NAD+, clinical effects on hard outcomes (mortality, cardiovascular events, physical function) still require longer-term and larger trials. It is very likely that oral precursors like NR cannot achieve the extremely high plasma peaks of NAD+ IV administration, which explains clinically why they are reserved for maintenance and IV for acute intervention.