IV NAD+ Infusions Are Popular in Wellness Clinics, but the Human Evidence Remains Thin

NAD+ is a coenzyme involved in energy metabolism, DNA repair and cellular stress responses. It is a required substrate for sirtuins, PARPs and CD38. Its supposed decline with age has driven interest in boosting it, and IV NAD+ infusions have spread through commercial wellness settings. This review asks what human evidence actually supports the practice.

The authors conducted a structured narrative review rather than a systematic review or meta-analysis, citing too few randomized trials and too much heterogeneity. They searched PubMed and Google Scholar for studies from January 2018 to March 2026. They included human clinical studies, observational reports and case reports on IV or oral NAD+, NMN, NAM or NR, plus mechanistic work providing biological context. Older foundational studies were added through citation tracking. Findings were synthesized qualitatively, with attention to design, sample size, controls and follow-up.

The main result is that the evidence is sparse and low quality. Short-term IV NAD+ or NMN has been linked to transient rises in circulating NAD+ and changes in selected biomarkers of oxidative stress, inflammation and cellular metabolism. Limited exploratory reports describe self-reported improvements in sleep-related outcomes and neurologic symptoms. No randomized placebo-controlled trials of IV NAD+ were identified. Reported adverse effects were nausea, cramping, flushing and chest discomfort. The mechanistic section stresses that infused NAD+ is likely hydrolyzed outside cells by ectonucleotidases such as CD38 into NAM and ADP-ribose. It is therefore unclear whether intact NAD+ enters cells or whether effects come from metabolites such as NAM and NMN re-entering the salvage pathway. The review also notes there is no direct evidence that IV delivery is superior to oral precursors.

The review also challenges the premise behind the field. A large cross-sectional cohort (Trętowicz et al., 2026) found whole-blood NAD+ was not independently associated with chronological age once disease burden and comorbidity were accounted for. Another analysis argues NAD+ decline should be viewed in the context of metabolic dysfunction rather than aging itself. The authors suggest future trials screen participants by measured NAD+ status instead of age.

For clinicians and consumers, the conclusion is cautious: IV NAD+ cannot be considered evidence-based practice. Biomarker changes should not be read as proof of anti-aging, cognitive or metabolic benefit. The authors call for randomized controlled trials with standardized protocols, rigorous human pharmacokinetics, comparison against oral precursors and clinically meaningful endpoints. They also flag commercial and publication bias in the existing literature. Note that the available text was truncated partway through the mechanisms section, so this summary relies mainly on the abstract, introduction, methods and early results.