If you have started looking into NAD+, you have probably noticed it comes in more than one form. The same compound is offered as an injection, as a nasal spray, as an IV drip, and as patches. It is a reasonable thing to be confused by, because most places selling it only offer one and tend to explain why theirs is the sensible choice.
Here is the honest version of how the two most common at-home forms differ.
What NAD+ actually is
NAD+ stands for nicotinamide adenine dinucleotide. It is a coenzyme found in every living cell, and it takes part in a great many of the reactions your cells use to turn food into usable energy, along with processes involved in DNA repair and cellular maintenance.
NAD+ levels are understood to decline as people age. That observation is what most of the interest is built on — the reasoning being that if levels fall over time, raising them again might matter. Whether supplementing it produces the outcomes people hope for is still an open research question, and worth holding onto as you read anything on this subject, including this page.
The real difference is how it gets in
Both forms contain the same molecule. What separates them is the route it takes into your body — and that route affects how much arrives, how quickly, and how predictably.
NAD+ is a large, fragile molecule. Swallowed, very little survives digestion intact, which is why oral NAD+ is generally considered poorly absorbed and why precursors like NR and NMN exist as a separate approach. Every other delivery method is essentially an attempt to work around that problem.
NAD+ injection
Subcutaneous injection places NAD+ into the tissue just under the skin, bypassing digestion entirely. It is typically self-administered at home with a small insulin-style needle, following a schedule your provider sets.
What it offers: the most direct route short of an IV, and the most established dosing conventions of the at-home options, since it is closest to how NAD+ has been studied and given clinically.
What to weigh: it involves needles, which for some people is a genuine obstacle rather than a minor inconvenience. Injection sites can be tender or red. It requires proper storage and safe sharps disposal, and it is less convenient to travel with.
NAD+ nasal spray
Intranasal delivery absorbs NAD+ through the tissue lining the nasal cavity, which is thin, densely supplied with blood vessels, and absorbs some compounds efficiently.
What it offers: no needles, no sharps disposal, and a routine most people find easy to keep. It travels well and takes seconds. For anyone who would simply not follow through with injections, a form actually used is worth more than a theoretically better one abandoned in a drawer.
What to weigh: absorption through the nasal lining is less predictable than injection. It varies with technique, with how much of the dose runs off rather than absorbing, and with whether your nose is clear — congestion, allergies or a cold can all affect it. The research base for intranasal NAD+ is also thinner than for injection.
Side by side
- Absorption: injection is more direct and more consistent. Nasal spray is less predictable and varies with technique and congestion.
- Convenience: nasal spray is easier — no needles, no sharps, simple to travel with.
- Comfort: nasal spray avoids needles entirely. Some people find the spray briefly stings or drips.
- Research base: injection has more behind it. Intranasal delivery is newer and less studied.
- Sticking with it: the form you will genuinely keep up with tends to matter more than small differences on paper.
What the research does and does not show
It is worth being plain about this, because much of what is written about NAD+ online is not.
NAD+ biology is real and well established. It is a genuine coenzyme doing genuine work in your cells, and the age-related decline is documented. What is far less settled is what supplementing it accomplishes in healthy people — how much reaches cells by any given route, what dose matters, and which outcomes actually follow. Much of the human research is early, small, or still underway.
Anyone telling you the science is settled is ahead of the evidence. A provider who says some of this is still being worked out is being straight with you.
Questions worth asking
- Which form do you recommend for me, and what makes you say so?
- What dose and schedule, and how would we know whether to adjust?
- Where is it compounded, and is that pharmacy licensed?
- What should I expect in the first few weeks, and what would mean stopping?
- How does this interact with anything else I take?
If you want more on that last area, we have written separately about how to choose a peptide provider and about 503A and 503B compounding pharmacies.
So which one
There is no single right answer, and anyone who gives you one without knowing your history is guessing.
Broadly: injection is the more direct and better-studied route, and tends to suit people who are comfortable with needles and want the most established option. Nasal spray suits people for whom needles are a real barrier, or who travel often, and who would rather follow a routine consistently than optimise one they will abandon.
But that is general information, not advice for you. Your history, what else you take, what you are hoping for, and your own honest sense of what you will stick with all belong in the decision — and that conversation belongs with a licensed clinician who can ask about things a web page cannot.
Compounded medications are not FDA-approved. Nothing here is medical advice, and it is not a substitute for talking with a qualified provider. Sereneque does not provide medical care, prescribe medications, or process payments — a licensed clinician determines whether any treatment is appropriate for you.
This article is general information. It is not medical advice, and nothing here is a recommendation to use any particular treatment. Decisions about your health belong between you and a licensed clinician who knows your history.