NAD+ dosage and evidence

What is NAD+?

How does NAD+ work?

It carries electrons, a key step in turning food into energy. Sirtuins and PARPs, enzymes linked to ageing and DNA repair, use it up as they work. The idea is that raising NAD+ helps mitochondria, the cell's power plants, and helps cells repair themselves.

What have studies in people found about NAD+?

One study in people, and it measured blood chemistry, not benefit. The pills the body turns into NAD+, such as NMN, have their own pages.

• Grant 2019: a six-hour NAD drip in a small group of people. NAD and its breakdown products in the blood did not rise for the first 2 hours. Nobody's symptoms, energy or health were recorded.
• Reviews of how NAD works, and of the pills NMN and NR, are listed so the science is not hidden. They are not studies of a drip.

What this does not tell you: No study with a comparison group has shown that an NAD drip or shot makes a person feel, think or age better. Clinics sell the chair anyway. The missing study is the finding.

What do people who took NAD+ report?

This is what real people say happened to them, good and bad. Nobody measured it. A report cannot tell a real effect from the lift people get just from expecting it to work, from a diet or training change made at the same time, or from what was really in the vial. We still put it near the top. It is the next best thing to a study in people: what happens when real people use it, including what goes wrong.

• Route is the main division in the discussion. A clinic drip, a do it yourself shot under the skin, and pills that the body turns into NAD+ are treated as three different things rather than as interchangeable, and people are frequently corrected for conflating them.
• Infusion is described as slow and unpleasant. Nausea, cramping, chest pressure, sweating, flushing and a racing heart during the drip come up consistently, and the standard response described is to slow the drip down, which is why sessions are described as running for hours rather than minutes.
• Those symptoms are reported as stopping when the infusion stops. That is the single point most accounts agree on.
• Injected amounts described are small, in the region of twenty to fifty milligrams every day or every second day, and nausea is reported at that route too, attributed by posters to how quickly it enters circulation.
• Sleep reports go both ways. Some describe it improving and others describe sleep becoming less restorative and stopping for that reason after a few weeks. Accounts of stopping because nothing changed are present alongside the favourable ones.
• Practical information is described as hard to find. Posters note that what is published compares oral against intravenous and says very little about the small repeated injections many of them are actually giving themselves.

Sources: NAD+ injection dosing threads on ExcelMale read directly, and NAD+ subforum threads on LongeCity covering infusion and push versus drip, surfaced by site-restricted search, September 2026. Nothing above is attributed to any specific post and no post is reproduced.

The evidence, in charts

The studies we cite

• Study in people2019
  A pilot study investigating changes in the human plasma and urine NAD+ metabolome during a 6 hour intravenous infusion of NAD

  The first time anyone measured what a NAD drip actually does in people, and it measured nothing about whether it helps. Blood was sampled during a six hour infusion. For the first two hours, NAD in the blood did not go up, nor did its breakdown products. The likely explanation is that tissues take it up or destroy it fast. No symptom, no energy measure and no health outcome was recorded. So this tells you where the drug goes, and nothing about what it does.

  First human data on IV NAD+: no rise in plasma NAD+ or metabolites for the first 2 hours of infusion, consistent with rapid tissue uptake or breakdown; no efficacy outcomes measured.

  PMID 31572171 Frontiers in Aging Neuroscience
• Review of studies2021
  NAD+ metabolism and its roles in cellular processes during ageing

  A review of NAD+ biology. NAD+ is a helper molecule for enzymes tied to ageing. Levels in the body fall with age in rodents. They fall in people too. Whether topping it up helps ageing people is still unknown.

  NAD+ is a redox coenzyme and cofactor for sirtuins, CD38 and PARPs; tissue NAD+ declines with age in rodents and humans, but whether repletion benefits ageing humans is still unknown.

  PMID 33353981 Nature Reviews Molecular Cell Biology
• Review of studies2018
  NAD+ intermediates: the biology and therapeutic potential of NMN and NR

  A review of NMN and NR, pills the body turns into NAD+. In animal studies they eased signs of ageing. Whether that happens in people had not been tested yet.

  Supplementing NAD+ precursors ameliorates age-associated pathophysiology in preclinical models; translation to humans remained to be tested.

  PMID 29249689 Cell Metabolism