K4 Elite
K4 Elite
Human data must be separated by molecule. Direct NAD+ administration has been studied only in small studies: a pharmacokinetic pilot of a 6-hour intravenous infusion at 3 µmol/min (Grant 2019) and a retrospective tolerability review of 500 mg IV NAD+ versus IV nicotinamide riboside on four consecutive days in a commercial clinic (Reyna 2026). The larger randomised, placebo-controlled trials involve oral NAD+ precursors rather than NAD+ itself: nicotinamide riboside (NR) 100-1,000 mg/day for 8 weeks (Conze 2019), 1,000 mg/day for 6 weeks in a crossover (Martens 2018) and 2,000 mg/day for 12 weeks in obese men (Dollerup 2018), and nicotinamide mononucleotide (NMN) 250 mg/day for 10 weeks in prediabetic postmenopausal women (Yoshino 2021). Oral precursor trials report tolerability similar to placebo; intravenous NAD+ is associated with infusion-rate-dependent symptoms (gastrointestinal upset, chest pressure, increased heart rate) that resolve when the infusion ends.
Each row records what a published study did: who it enrolled, the regimen it administered to those subjects, and what it reported. These are historical study descriptions, not protocols to follow.
| Study | Population | Regimen as reported | Primary findings |
|---|---|---|---|
| Grant et al., Front Aging Neurosci 2019 (open-label pharmacokinetic pilot; intravenous NAD+) | Healthy adult participants (small pilot cohort) | Participants received a 6-hour intravenous infusion of NAD+ at 3 µmol/min while plasma and urine NAD+ and metabolites (nicotinamide, methylnicotinamide, ADPR, NMN) were measured. | No change in plasma NAD+ or metabolites was observed until after 2 hours, indicating rapid and complete clearance from plasma at that rate; urinary NAD+ and methylnicotinamide increased by 6 hours. |
| Reyna et al., Front Aging 2026 (retrospective chart review; intravenous NAD+ vs intravenous NR) | Clients of a commercial infusion clinic (small cohorts) with 30-day follow-up | Clients received 500 mg NAD+ IV or 500 mg NR IV on four consecutive days; symptoms, infusion time, blood pressure, heart rate and ALT/AST/hsCRP/BUN-creatinine/TSH were extracted from records. | NAD+ IV recipients reported moderate-to-severe gastrointestinal symptoms, increased heart rate and chest pressure during infusion (mean infusion time 97 min vs 37 min for NR IV); all symptoms resolved on completion, and no significant changes in ALT, AST, hsCRP, BUN/creatinine or TSH were seen. |
| Martens et al., Nat Commun 2018 (randomised, double-blind, placebo-controlled crossover; oral NR precursor) Registry: NCT02921659
|
Healthy middle-aged and older adults (30 enrolled, 24 completed) | Participants received oral nicotinamide riboside chloride 1,000 mg/day or placebo for 6 weeks each in a 2 x 6-week crossover. | Chronic NR supplementation was reported as well tolerated with no serious adverse events and increased NAD+ metabolism; the authors suggest future trials assess blood pressure and arterial stiffness. |
| Conze, Brenner & Kruger, Sci Rep 2019 (randomised, double-blind, placebo-controlled; oral NR precursor) | Healthy overweight men and women | Participants received oral NR chloride (NIAGEN) 100 mg, 300 mg or 1,000 mg daily, or placebo, for 8 weeks. | Whole-blood NAD+ increased dose-dependently by 22%, 51% and 142% within 2 weeks and was maintained; there were no reports of flushing and no significant differences in adverse events between NR and placebo groups or across doses. |
| Dollerup et al., Am J Clin Nutr 2018 (randomised, double-blind, placebo-controlled; oral NR precursor) Registry: NCT02303483
|
40 healthy sedentary men with BMI > 30 kg/m2, aged 40-70 years | Men received oral NR 1,000 mg twice daily (2,000 mg/day) or placebo for 12 weeks; insulin sensitivity was measured by hyperinsulinaemic-euglycaemic clamp. | Insulin sensitivity, endogenous glucose production, energy expenditure and body composition were not changed by NR; no serious adverse events due to NR were observed and safety blood tests were normal. |
| Yoshino et al., Science 2021 (randomised, double-blind, placebo-controlled; oral NMN precursor) Registry: NCT03151239
|
Postmenopausal women with prediabetes who were overweight or obese (registry enrolment 25) | Women received oral NMN 250 mg/day or placebo for 10 weeks. | Insulin-stimulated glucose disposal (clamp) and skeletal-muscle insulin signalling increased after NMN but not placebo; the abstract does not report adverse events. |
Effects recorded in the cited reports. Frequencies are those the source reported, in the population that source studied.
| Effect | Frequency / context | Source |
|---|---|---|
| Gastrointestinal symptoms, chest pressure and increased heart rate during IV NAD+ infusion (infusion-rate dependent) | In the retrospective clinic review (500 mg NAD+ IV on four consecutive days), NAD+ IV recipients reported moderate-to-severe gastrointestinal symptoms, increased heart rate and chest pressure during infusion, prolonging mean infusion time to 97 min; symptoms resolved on completion. NR IV recipients reported only minor tingling and mild cramping. | Intravenous infusion of nicotinamide adenine dinucleotide (NAD+) versus nicotinamide riboside (NR): a retrospective tolerability pilot study in a real-world setting (Front Aging 2026) ↗ |
| Flushing (oral NR precursor) | No reports of flushing with NR 100-1,000 mg/day for 8 weeks, and no significant difference in adverse events versus placebo (Conze 2019); NR did not raise LDL cholesterol in that trial. | Safety and Metabolism of Long-term Administration of NIAGEN (Nicotinamide Riboside Chloride) ... (Sci Rep 2019) ↗ |
| Serious adverse events (oral NR precursor, high dose) | None attributed to NR at 2,000 mg/day for 12 weeks in 40 obese men; safety blood tests were normal (Dollerup 2018). | A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men (Am J Clin Nutr 2018) ↗ |
| Preclinical toxicology of NR (rat) | In 90-day rat studies NR at 300, 1,000 and 3,000 mg/kg/day showed a toxicity profile similar to equimolar nicotinamide at the highest dose, with liver, kidney, ovaries and testes as target organs; NOAEL 300 mg/kg/day, LOAEL 1,000 mg/kg/day; NR was not genotoxic. | Safety assessment of nicotinamide riboside, a form of vitamin B3 (Hum Exp Toxicol 2016) ↗ |
No interactions with a verifiable citation have been indexed for this compound.
Exclusions and label contraindications recorded in the cited sources.