In a 60 day, randomized, double‑blind, placebo-controlled trial with 80 middle‑aged participants, taking 300–900 mg/day of NMN significantly increased blood NAD⁺ levels and improved physical performance (6‑minute walking distance). The 600 mg and 900 mg groups experienced the strongest benefits. Participants also reported better general health without any adverse events The Wall Street Journal+15PubMed+15New York Post+15.
Another study on healthy older men aged 65+, taking 250 mg/day of NMN for 12 weeks, showed increases in NAD⁺ levels and improvements in gait speed and grip strength, suggesting benefits for musculoskeletal function and sarcopenia prevention PMC.
NR (Nicotinamide Riboside)
In a 6 week randomized crossover trial in healthy middle-aged and older adults, daily dosing of NR (up to 2,000 mg/day) was well tolerated and significantly raised NAD⁺ and related metabolites. NR also showed trends toward improved blood pressure and arterial stiffness CNIBio+15PubMed+15PMC+15.
In 22 older adults, oral NR (500 mg twice daily for 6 weeks) increased neuronal NAD⁺ in brain-derived extracellular vesicles and reduced Alzheimer’s‑related biomarkers (e.g., pJNK, pERK1/2, Aβ42) — suggesting potential brain-protective effects PubMed+1Reddit+1.
A study in older individuals with mild cognitive impairment (MCI) supplemented with 1 g/day NR for 8 weeks found reduction in phosphorylated tau (pTau217) — a key Alzheimer’s biomarker — though cognitive scores remained unchanged during the trial period .
Supporting Context & Expert Commentary
A comprehensive overview article notes that NAD⁺ declines with age and metabolic stress. While animal studies show that NMN and NR supplementation can extend healthspan, human trials are still limited, pointing to modest benefits in exercise performance, insulin sensitivity, and inflammation PubMed+15Verywell Health+15PMC+15.
A 2025 news piece highlights NMN as notably promising, supported by experts like Dr. David Sinclair. Reported benefits in small studies include better metabolism, cardiovascular function, cognitive clarity, and skin condition. However, NMN is still under regulatory review in some regions Indiatimes.
Another article emphasizes that while researchers like Leonard Guarente and Charles Brenner advocate for NAD⁺ precursors, the field remains controversial, with debates over scientific rigor and efficacy PubMed+2The Wall Street Journal+2Verywell Health+2.
Takeaway for Virevia
NMN and NR both effectively raise NAD⁺ levels in humans and may support metabolic, cognitive, and physical health when taken consistently.
Most trials report no significant adverse events, even at relatively high doses.
Effects on inflammation markers, exercise capacity, and biomarkers of neurodegeneration are promising.
However, evidence remains preliminary; larger and longer-duration clinical trials are still needed.
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