Reyna · Frontiers in aging 2026 · Retrospective comparative cohort study · n=?

Intravenous infusion of nicotinamide adenine dinucleotide (NAD + ) versus nicotinamide riboside (NR): a retrospective tolerability pilot study in a real-world setting.

Cited 3 times in the scientific literature.

Level 3 - non-randomized controlled study

Retrospective comparative cohort study of electronic medical records

PubMed 41704678 · doi:10.3389/fragi.2026.1652582 · record verified 2026-08-29

What was done

Researchers conducted a retrospective chart review of clients at a commercial wellness clinic who received four consecutive daily 500 mg intravenous infusions of either NAD+ or nicotinamide riboside (NR), with 30 days of follow-up. They evaluated acute symptoms, infusion duration, vital signs, safety biomarkers (ALT, AST, hsCRP, BUN/creatinine, TSH, ALP), and exploratory metabolic markers (HbA1c, fasting glucose, and lipid panel).

What was found

Participants receiving IV NAD+ experienced moderate to severe gastrointestinal symptoms, increased heart rate, and chest pressure, resulting in an average infusion time of 97 minutes. Participants receiving IV NR experienced minor tingling in the tongue, jaw, or arm and mild cramping, averaging 37 minutes of infusion time. All symptoms resolved upon completion of the infusion. Standard safety labs (ALT, AST, hsCRP, BUN/creatinine, TSH) showed no significant changes in either group, though ALP decreased significantly within normal ranges in the NAD+ group. Over 30 days, the NR group showed a significant reduction in HbA1c, while the NAD+ group showed a significant reduction in HDL-C. Fasting glucose and LDL-C were unchanged in both groups. Numerical biomarker values and sample sizes were not provided in the abstract.

Why it matters

Direct comparative data on intravenous NAD+ therapies in commercial settings are rare. These findings suggest IV nicotinamide riboside is better tolerated and faster to administer than IV NAD+, though both show distinct exploratory metabolic changes that warrant rigorous prospective testing.

Limits

The abstract does not state the sample size, exact baseline demographics, or quantitative biomarker measurements. The study was non-randomized, retrospective, and conducted in a commercial wellness setting without a placebo control, creating high potential for selection bias and confounding. Outcomes beyond 30 days were not evaluated.

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