Does a NAD+ infusion do something that an NMN pill does not?
There is no study that directly compares a NAD+ infusion with an oral NMN pill, so any advantage of the infusion has not been demonstrated. If you want to start NAD+ support, oral NMN is the only option with some clinical backing.
There is no direct comparative study that has tested a NAD+ infusion and an oral NMN pill in the same people using the same outcome measures. Any claim about what an infusion 'does additionally' therefore cannot be substantiated on the basis of available research.
What oral NMN does do has by now been mapped out reasonably well. In a randomised double-blind study in healthy middle-aged adults, blood NAD+ concentrations rose measurably and in a dose-dependent manner at 300, 600 and 900 mg per day, with the greatest increase at 600 and 900 mg. That is better than nothing, but researchers also note that the effects in humans are smaller than animal studies would lead one to expect. The pill raises NAD+ in the blood, but whether that also sufficiently raises NAD+ levels in the heart, muscles, brain or liver remains unclear. In people with obesity and a fatty liver, for example, clinical effects have so far been modest.
Intravenous administration of NADH (a related molecule, not the same as NAD+) has been studied in 15 Parkinson's disease patients. That small study without a control group showed an improvement in motor symptoms and higher levodopa availability in the blood. However, this says nothing about NAD+ infusions in healthy people or in ageing people without Parkinson's disease, and the strength of evidence from that single study is too weak for firm conclusions.
Theory suggests that an infusion bypasses the intestinal barrier and delivers direct peak concentrations in the blood, but whether those peak levels reach target tissues more effectively than a pill has not been demonstrated. As long as there is no comparative study, an infusion is primarily more expensive and more invasive, not demonstrably more effective.
The claims are based on several small to medium-sized RCTs and open-label studies of oral NMN (PMID 36482258, 36797393, 38191197), two review articles on the gap between animal and human studies (PMID 37335049, 33932956), and one small observational study of intravenous NADH in Parkinson's disease (PMID 9013405). No comparative study between a NAD+ infusion and oral NMN is available in the source texts.
Are NAD+ supplements (NMN/NR) worth it?
NMN and NR demonstrably raise NAD+ in your blood and appear to be safe, but whether you will actually notice any difference in muscle strength, heart function or memory? That is far from proven in humans. Note too: NR is authorised as a supplement in the EU, NMN is not (yet).
What works better to raise NAD+: NMN or NR?
Based on the only direct head-to-head comparison study in humans, NMN and NR perform equally well for raising NAD+, so for now you can base your choice on price or personal preference.
Which supplements or medications are best not combined with NAD+?
The combination of NAD+ supplements (particularly nicotinamide) with platinum-based chemotherapy is the most concrete reason for caution; for other interactions the indications are preliminary but worth discussing with your doctor if you are using multiple substances.
Does a NAD infusion (IV drip) make sense?
A NAD infusion has no proven advantage over cheaper oral supplements, and even those show hardly any demonstrable effect in healthy people. Consider an infusion only after consulting your doctor, especially if you have a specific medical condition.
What is NAD+ and what does it do in your body?
NAD+ is an indispensable molecule for energy, DNA repair and cell health, but the question of whether you should actively raise those levels for better health has not yet been answered for humans.
What does NAD+ do for your brain?
NAD+ is biologically crucial for your brain and declines with age, but whether supplementation via NMN or other means genuinely protects humans has not yet been convincingly demonstrated. Wait for the results of larger clinical studies before drawing firm conclusions.