# NAD+ safety in the Research Literature: Trials, IV Risks, Recalls > NAD+ safety reviewed: oral precursors were well tolerated in RCTs with no significant adverse-event difference from placebo; compounded IV NAD+ faced an FDA Class I endotoxin recall. Cited. What controlled trials reported on tolerability, where the FDA Class I recall fits, and why the IV route carries the weakest evidence and the documented quality risk. ## The short version On NAD+ safety, the evidence splits cleanly by route. Oral precursors (NMN and NR — building blocks the body converts into NAD+) were generally well tolerated in randomized trials, with no significant difference in side effects from placebo at the doses tested [4][3]. The injectable side is different: IV NAD+ is a compounded, unapproved therapy with little controlled evidence, infused NAD+ leaves the blood within hours, and a compounded NAD+ injection was subject to an FDA Class I recall for endotoxin contamination. This page summarizes the safety record. It is not medical advice and recommends no product or dose. ## Reported tolerability and side effects in studies In controlled oral trials, NAD+ precursors were well tolerated. The 8-week NR study at 100-1000 mg/day reported no flushing, no elevation of LDL cholesterol, no disruption of one-carbon metabolism, and no significant adverse-event difference from placebo at any dose [4]. The NMN dose-ranging trial (300-900 mg/day for 60 days) reported no safety issues at any dose [3]. The 10-week NMN insulin-sensitivity study likewise reported the intervention as safe over its duration [8]. Reported effects on the injectable side are different in character. IV-infusion accounts describe flushing, nausea, and chest or abdominal discomfort that are tied to infusion rate — run too fast, the infusion is less comfortable. Those effects are described as transient. By contrast, the oral-precursor trials simply did not separate from placebo on adverse events at the doses studied [4][3]. The most important tolerability variable in this literature is route and rate, not the molecule alone. ### How long do NAD side effects last? Reported IV-infusion effects — flushing, nausea, chest or abdominal discomfort — are tied to infusion rate and are described as transient. In the oral-precursor trials there was no significant adverse-event difference from placebo at the doses tested [4][3]. ## NAD injection and IV NAD+ in the literature An NAD injection or IV infusion delivers NAD+ parenterally in wellness and clinical settings. It is a compounded, unapproved therapy, and the published evidence behind it is the weakest in this field — mostly pilot or pharmacokinetic work rather than large randomized trials. Pharmacologically, the route faces an inherent problem: infused NAD+ is rapidly cleared from plasma, with near-complete removal within roughly the first two hours of infusion in one pilot study [13], and extracellular NAD+ is enzymatically degraded before cellular uptake [13]. ### NAD IV therapy: evidence and quality risks Controlled evidence for NAD IV therapy is limited. Beyond the efficacy gap, there is a documented quality risk: the FDA issued a Class I recall — its most serious category — of a compounded NAD+ injection for elevated bacterial endotoxin. Compounded injectables are not FDA-approved products, and purity and sterility are not guaranteed across compounders. Reconstituted injectable NAD+ should be kept cold and protected from light, and infusion-rate effects (flushing, nausea, discomfort) are reported when sessions run too fast. ## Regulatory and supplement status NAD+ is not an FDA-approved drug. It is marketed as a dietary supplement, and as a compounded injectable in wellness settings. Several facts belong in any honest safety read: - **NMN's supplement status is contested.** The FDA has taken the position that NMN is excluded from the dietary-supplement definition because it was authorized for investigation as a drug. This is a marketplace dispute over classification — present it as that, not as "NMN is banned or illegal." - **Compounded IV NAD+ carries documented quality risk.** The Class I endotoxin recall is the concrete example; compounded injectables are unapproved and vary by compounder. - **Supplement-grade purity varies.** Actual content and purity differ across products, and third-party testing is not guaranteed. - **A cancer-context caution exists.** NAD+ supports proliferating cells, and a theoretical concern is that boosting it could fuel existing cancers; NAD+ in oncology has dual, context-dependent roles, so caution is noted for cancer populations [5]. - **WADA:** NAD+ and its precursors (NMN, NR, nicotinamide) are not prohibited by WADA. ### What is the downside of taking NAD+? Oral NAD+ is poorly absorbed intact, so precursors are the studied oral route. The 2025 *Nature Metabolism* review found human efficacy for hard clinical endpoints remains preliminary [7], and compounded IV NAD+ carries contamination risk — an FDA Class I endotoxin recall has been issued. ### Is it safe to take NAD daily? In controlled trials, oral precursors raised blood NAD+ over weeks of daily dosing with no significant adverse-event difference from placebo at the doses tested [4][3]. This describes study findings, not a recommendation to take any product. --- A safety-first reel of the NAD+ literature — what the trials cut to, where the evidence drops off, and nothing dispensed, prescribed, or sold.