Dr. Pep

Peptides · Coenzyme (injected/IV NAD+ and its precursors)

NAD+: what the studies show

Every line below comes from a study, label or regulator record, checked by two models, with the source linked. Information, not medical advice. For adults 18+.

What it is

  • NAD+ is a molecule every cell makes and uses to run energy metabolism, DNA repair and other enzymes. Levels in the body are reported to fall with age.[1][2]
  • Three different things get called 'NAD' and should not be mixed up. (1) NAD+ itself, given by IV drip or injection in wellness clinics or compounded. (2) Oral precursors such as nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN), which raise blood NAD+ levels. (3) Lab studies that only measure the body's own NAD+.[2][3]

Bottom line

  • Oral precursors, nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN), reliably raise blood NAD+ and are usually well tolerated, but trials show mixed or null results on health outcomes, and NR did slightly worse than placebo in a large Parkinson trial. Those results are for the precursors, not for NAD+ itself. Controlled trials of injected or IV NAD+ are almost absent, and none test it for anti-ageing or wellness.[2][4][5][6]

What the human studies found

  • Review across forms: a systematic review of 33 human studies (28 randomised; searched to October 2025) found oral NR and NMN, which are NAD+ precursors rather than NAD+ itself, consistently raised NAD-related blood or cell markers and were generally well tolerated over weeks to months. Effects on function, metabolism and blood vessels were mixed and often null. It found no outcome trial of IV or intramuscular NAD+ itself for anti-ageing or wellness.[2]
  • Injected NAD+ itself (disease setting): in one single-centre RCT of 180 adults in China with heart failure from ischaemic heart disease, IV NAD+ for 7 days on top of usual care raised ejection fraction at 1 month more than placebo (45.44% versus 42.44%, p=0.024). Heart-event, NT-proBNP and symptom-class differences were not statistically significant.[7]
  • Injected NAD+ itself (wellness setting): a retrospective review of commercial clinic records compared 4 days of 500 mg IV NAD+ with 500 mg IV NR. NAD+ infusions caused moderate to severe stomach symptoms, faster heart rate and chest pressure, and took 97 minutes on average versus 37 for NR. It had no control group and tested no benefit.[3]
  • Precursor, not NAD+ (nicotinamide riboside, an oral NAD+ precursor): NOPARK was an RCT in 393 analysed adults with early Parkinson disease given NR 500 mg twice daily for 52 weeks. The motor-and-symptom score worsened by 2.45 points on NR and improved by 0.27 on placebo (difference 2.72, favouring placebo, p=0.02). Non-motor symptoms also worsened more on NR.[4]
  • Precursor, not NAD+ (nicotinamide riboside, an oral NAD+ precursor), other RCTs: in 40 obese men (1,000 mg twice daily for 12 weeks) NR did not improve insulin sensitivity, energy use or body composition. In 20 older adults with mild cognitive impairment (up to 1 g/day for 10 weeks) blood NAD+ rose 2.6-fold, but memory and thinking scores stayed the same as placebo. In 90 people with peripheral artery disease (6 months) NR improved 6-minute walk distance by 17.6 m over placebo, which the authors said needs a larger confirming trial.[5][8][9]
  • Precursor, not NAD+ (nicotinamide mononucleotide, NMN, an oral NAD+ precursor): in 80 healthy middle-aged adults (RCT, 300, 600 or 900 mg daily for 60 days) blood NAD rose in all NMN groups, most at 600 and 900 mg, with no safety issues found. In 36 healthy adults (RCT, 250 mg/day for 12 weeks) arterial stiffness did not differ significantly from placebo.[6][10]

Known risks and side effects

  • IV NAD+ at 500 mg a day caused moderate to severe stomach symptoms, increased heart rate and chest pressure during infusions in a clinic review; symptoms resolved when the infusion ended.[3]
  • A systematic review of 10 randomised trials of NADH and precursors (489 people) found side effects in all studies, most often muscle pain, nervous-system complaints, fatigue, sleep problems and headache. None was judged a serious health risk.[11]
  • In the NOPARK trial of nicotinamide riboside (an oral NAD+ precursor, not NAD+), 52 weeks of NR was associated with a slightly worse Parkinson symptom score than placebo.[4]

Legal status

  • FDA warning letter dated 2026-01-20 to GenoGenix LLC, a registered outsourcing facility, said it compounded drugs from bulk NAD+ that is not eligible for use in compounding under section 503B. It is the only dated NAD+ regulatory record in the records we hold.[12]

Sources

  1. [1] NAD+ therapy in age-related degenerative disorders: A benefit/risk analysis.
  2. [2] NAD⁺ supplementation for anti-aging and wellness: A PRISMA-guided systematic review of preclinical and clinical evidence.
  3. [3] Intravenous infusion of nicotinamide adenine dinucleotide (NAD+) versus nicotinamide riboside (NR): a retrospective tolerability pilot study in a real-world setting.
  4. [4] Nicotinamide Riboside for Patients With Early-Stage Parkinson Disease: The NOPARK Randomized Clinical Trial.
  5. [5] A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men: safety, insulin-sensitivity, and lipid-mobilizing effects.
  6. [6] The efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults: a randomized, multicenter, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial.
  7. [7] Effect of Nicotinamide Adenine Dinucleotide on Heart Failure Caused by Ischemic Cardiomyopathy: A Randomized, Placebo-Controlled Trial.
  8. [8] A randomized placebo-controlled trial of nicotinamide riboside in older adults with mild cognitive impairment.
  9. [9] Nicotinamide riboside for peripheral artery disease: the NICE randomized clinical trial.
  10. [10] Nicotinamide adenine dinucleotide metabolism and arterial stiffness after long-term nicotinamide mononucleotide supplementation: a randomized, double-blind, placebo-controlled trial.
  11. [11] Evaluation of safety and effectiveness of NAD in different clinical conditions: a systematic review.
  12. [12] FDA: Warning Letter, GenoGenix LLC (2026-01-20), compounded NAD+, thymosin beta-4, semaglutide, tirzepatide, retatrutide