NAD+ supplement or injection: what the difference is

Oral precursors, injectable NAD+ and IV drips compared on what each one has been measured to do, and where the honest gap in the evidence sits.

Key takeaways

  • Oral nicotinamide riboside and nicotinamide mononucleotide raise blood NAD+ in randomized placebo-controlled trials, which is the best established fact in this area.
  • Injectable and intravenous NAD+ bypass digestion and first pass metabolism, and have not been studied in randomized trials for pharmacokinetics or outcomes.
  • No published trial has compared oral precursors against injected NAD+ head to head, so any claim that one is a given number of times more effective is not coming from data.
  • Neither route has demonstrated a clinical outcome benefit in healthy adults. Both raise a biomarker.
  • The practical differences are cost, convenience, tolerability and whether a provider is involved.

Oral precursors raise blood NAD+ in randomized trials. Injectable NAD+ skips the digestive tract entirely.

No published trial has compared the two head to head for any outcome, which is the part most comparisons leave out.

What NAD+ is and why the route matters

NAD+ is a coenzyme required for energy metabolism and for the enzymes that repair DNA and regulate gene expression, including the sirtuins. Tissue levels decline with age in most measurements.

NAD+ itself is a large, charged molecule and is not efficiently absorbed intact from the gut. That is why oral products supply precursors instead, usually nicotinamide riboside or nicotinamide mononucleotide, which cells convert internally. It is also the argument behind injecting or infusing NAD+ directly.

What the oral trials show

Randomized placebo-controlled trials of nicotinamide riboside consistently raise whole blood NAD+ in a dose-dependent way and have been well tolerated over weeks to months. A trial of nicotinamide mononucleotide in prediabetic women reported improved skeletal muscle insulin sensitivity, a single small result rather than a settled finding.

What has not been shown is a downstream clinical benefit in healthy adults. Trials have been small and short, and results on blood pressure, arterial stiffness, physical function and inflammation have been mixed.

What is known about the injectable route

Less, and it is worth being plain about that. There are no randomized trials establishing the pharmacokinetics of subcutaneous NAD+ in humans, no dose-response data, and no outcome trials. Intravenous infusion is widely offered in wellness settings and is documented mainly in case reports and observational series, with a well recognized pattern of flushing, chest tightness and nausea when infused quickly, which is why infusions are run slowly.

The mechanistic argument for injection, that it avoids the gut and first pass metabolism, is reasonable pharmacology. It is an argument, not a measured result, and the numeric comparisons circulating online do not trace back to a published trial.

How to choose between them

  • Oral precursors: the route with actual randomized trial data behind the biomarker change, taken daily, low cost, well tolerated.
  • Subcutaneous injection: no gut absorption issue, less frequent administration, prescription and provider oversight required, no comparative data.
  • IV infusion: the most expensive route by a wide margin, clinic time required, the most reported infusion reactions, and no outcome data.
  • All three raise a biomarker. None has demonstrated that raising it changes how long or how well you live.

Where Baseline sits

Injectable NAD+ is listed in our catalog rather than available to order today, whether it fits you is a decision for an independent licensed provider, and we say openly that the outcome evidence for every route is still early. People who want the daily, inexpensive version of this are well served by an oral precursor, and we would rather tell you that than sell you a route you do not need.

If NAD+ is interesting to you because of energy or recovery, sleep, training, iron status and thyroid function are worth ruling out first. They are more likely to be the answer and they are cheaper to check.

What this means for you

Both routes raise NAD+. Only the oral route has randomized human data behind that claim, and neither route has outcome data. Choose on cost, convenience and provider oversight, and be skeptical of any specific multiplier comparing the two.

Therapies discussed here

References

  1. Martens CR, et al., chronic nicotinamide riboside supplementation is well tolerated and elevates NAD+ in healthy middle-aged and older adults, Nature Communications, 2018
  2. Airhart SE, et al., an open-label, non-randomized study of the pharmacokinetics of nicotinamide riboside and its effects on blood NAD+ in patients with heart failure, PLOS One, 2017
  3. Yoshino M, et al., nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women, Science, 2021
  4. Rajman L, et al., therapeutic potential of NAD-boosting molecules, the in vivo evidence, Cell Metabolism, 2018
  5. Covarrubias AJ, et al., NAD+ metabolism and its roles in cellular processes during ageing, Nature Reviews Molecular Cell Biology, 2021

More in Supplements