What NAD+ is, without the marketing
NAD+ is a coenzyme present in every cell, central to energy metabolism and to DNA repair processes. Levels decline with age, which is the observation the entire wellness category is built on.
The leap from that observation to 'raising NAD+ reverses ageing' is where the evidence thins out. A decline being associated with ageing does not establish that reversing it produces the benefits people are paying for.
Most of the strongest data is preclinical, in cells and animals. Human trials exist, are generally small, and mostly demonstrate that supplementation raises measurable NAD+ levels rather than that it produces the outcomes in the advertising.
The three delivery routes
Intravenous infusion. Delivered in a clinic over one to several hours. Bypasses digestion entirely and produces the largest measurable change in blood levels. It is also the most expensive route and the most time-consuming, and infusion-related discomfort is common enough that drips are run slowly.
Subcutaneous injection. Self-administered at home after training. Cheaper than IV, far more convenient, increasingly the format online providers offer.
Oral precursors. Nicotinamide riboside and nicotinamide mononucleotide, taken as capsules. NAD+ itself is poorly absorbed orally, which is why precursors are used. This is the cheapest route and the one with the most published human trial data, though the trials remain small.
Providers differ substantially in which routes they offer and how they price them; our NAD+ provider comparison sets them side by side.
What the research currently supports
There is reasonable evidence that oral precursors raise blood NAD+ levels in humans, and that they are generally well tolerated at studied doses in the short term.
Evidence for the outcomes people actually want, more energy, better cognition, slower ageing, is limited, mixed, and drawn from small studies. Some show modest effects on specific measures; others show nothing beyond placebo.
Long-term safety data is genuinely scarce, particularly for high-dose IV protocols, which have not been through the trial process that a licensed medication would face.
None of this means the category is worthless. It means the honest position is 'promising, unproven', and any provider telling you otherwise is ahead of the science.
Who should be more cautious
Anyone with an active cancer diagnosis or history should discuss this with their oncologist first. NAD+ is involved in cell metabolism and DNA repair, and the interaction with cancer biology is an active research question rather than a settled one.
People who are pregnant or breastfeeding, and people with significant liver or kidney disease, should not start on their own initiative.
Anyone on regular medication should check for interactions with a clinician or pharmacist rather than assuming a supplement is inert.
This is general information, not a recommendation for your situation. The right person to decide is a clinician who knows your history.
What to ask a provider before paying
Who supervises treatment, and are they licensed in my jurisdiction?
Where is the compounded product sourced, and can I see the pharmacy's credentials?
What dose, what protocol, and on what basis was it chosen?
What does a full course cost, not a single session?
What monitoring is included, and what happens if I react badly?
Providers that answer these plainly are the ones worth considering. You can compare how the main services handle supervision and sourcing in our NAD+ rankings, including AgelessRx.
A reasonable way to think about the money
IV protocols are the most expensive option by a wide margin, and the marginal benefit over other routes has not been demonstrated in the way the price difference implies.
If you want to try the category, the cheapest well-studied route is an oral precursor, and it is the one where you risk the least while the research matures.
Whatever route you pick, decide in advance what you are measuring and over what period. 'I feel a bit better' after a $1,200 course is not something anyone can evaluate, including you.