- The basic biology is settled: NAD+ is a coenzyme in every living cell, central to turning food into cellular energy and to the enzymes that maintain and repair DNA.
- Measured NAD+ levels decline with age. That is a correlation, and correlations do not prove that restoring the level restores anything else.
- Human trials of NAD+ precursors reliably raise blood levels. Hard human outcomes, energy, cognition, longevity, remain thin, and injection-specific trials are thinner still.
- Our honest label is the one on the product page: promising, not proven. Some members report steadier energy and clarity. Many notice nothing and stop.
- The grade changes when the evidence changes, and this page changes with it.
What NAD+ actually is
Start with the part nobody disputes. Nicotinamide adenine dinucleotide is a coenzyme found in every living cell, yours, your dog's, the yeast in your bread. Its best-established job is in metabolism: NAD+ carries electrons in the chain of reactions that converts what you eat into usable cellular energy. Without it, that chemistry simply does not run.
It has a second job that explains most of the excitement around it. NAD+ is consumed by families of enzymes involved in cellular maintenance, including the enzymes that repair damaged DNA and the sirtuins, proteins studied for their role in how cells respond to stress and aging. When those enzymes work, they spend NAD+ the way an engine spends fuel.
None of that is wellness marketing. It is textbook biochemistry, taught in every introductory course, and it is genuinely important. The molecule is not the controversy. What happens when you inject more of it into an adult human is.
The aging observation
Here is the observation the entire NAD+ industry is built on: measured NAD+ levels in human tissue decline as we get older. That finding is consistent across studies and we are not aware of serious researchers who dispute it.
Now, what does it prove? Less than the ads suggest. A decline that tracks age is a correlation. It does not establish that the decline causes the things we dislike about aging, and it does not establish that pushing the level back up reverses them. Plenty of things track age faithfully, gray hair among them, and recoloring gray hair does not make anyone younger. The decline could be a driver of age-related change, a passenger alongside it, or some of each, and researchers are still working out which.
To be fair to the hypothesis: it is a good hypothesis. The enzymes that maintain cells spend NAD+, levels fall with age, and in laboratory animals, raising NAD+ has improved various markers of health. That chain of reasoning is why serious scientists study this molecule. A good hypothesis is a reason to run trials. It is not a result.
The human evidence, graded
Grade the evidence in three tiers, because it comes in three tiers.
The mechanistic and preclinical tier is strong. Cell and animal studies of NAD+ restoration are numerous and often striking. This is the tier press releases quote. It is also the tier with the worst track record of translating to people: findings in mice frequently do not survive contact with humans, in this field and in every other.
The human precursor tier is real but modest. Compounds like nicotinamide riboside and NMN, which your body converts into NAD+, have been through a number of human trials. Those trials show the levels in blood can be raised, and short-term use has looked generally safe. That matters: it means the strategy is testable in people. What the trials have not yet delivered is consistent proof of the outcomes people are actually buying, more energy, sharper cognition, longer life. A 2020 systematic review of human trials of NAD+-raising therapies, linked in the sources below, found only a small number of randomized, adequately powered studies across several decades of interest, and concluded the results were promising but still speculative, with most tested uses resting on a single small trial that has not been replicated.
The injection tier is the thinnest of the three. Most human research uses oral precursors. Trials of injected NAD+ itself, the form used in drip lounges and in our own protocol, are fewer and smaller still. So anyone selling injected NAD+ is extrapolating: from settled biology, from precursor data, and from reported experience. That includes us, and we would rather tell you than have you find out.
What injections add, and what they don't
Why inject at all? Because of a genuine absorption problem. Taken by mouth, NAD+ is broken down in digestion before it is absorbed intact, which is why oral products are precursors rather than the molecule itself. Injection puts NAD+ into circulation directly. That is the honest case for the route: it solves delivery.
What the route does not solve is the evidence gap. Getting more of a molecule into the blood is only useful if raising that molecule produces the benefit you wanted, and that second step is exactly the unproven one. A clever route to an unproven destination is still an unproven destination. Keep that distinction in mind when a clinic's menu implies the needle itself is the proof.
“A molecule can be essential in every cell you have and still be unproven in a syringe. Both of those things are true of NAD+ today.”
Dr. Alana Reyes, MD · Medical Director
Why we sell it anyway, and say all this out loud
A fair question at this point: if the outcome evidence is thin, why does Parke offer NAD+ at all? Three reasons, none of them secret.
First, the biology is plausible in a way most wellness products are not. This is not a molecule invented by a marketing department. It is central, its decline with age is documented, and serious laboratories are actively testing whether restoring it matters. Promising is a real category, distinct from proven and distinct from nonsense, and NAD+ sits in it.
Second, some members report benefits they value: steadier afternoons, a feeling of clarity, easier recovery. We report that carefully, because subjective reports are the weakest form of evidence and include every placebo effect known to medicine. But members are adults, the reports are real to the people making them, and a supervised, honestly priced way to run the experiment is better than the alternatives most people find first.
Third, and this is the part we consider non-negotiable: we can offer it without lying about it. The product page says the human evidence is early, small, and mixed, that many people notice nothing, and that nothing is guaranteed. Your clinician says the same before you spend anything. The label we use internally and publicly is promising, not proven, and a fair trial at Parke has an exit built in: around twelve weeks, your clinician reviews whether it is earning its place, and if you cannot tell the difference, they will say stop rather than keep shipping it.
Who tends to consider it
The people who ask us about NAD+ mostly fall into a few groups. People already paying for drip-lounge infusions who want the same molecule without the chair, the hours, and the per-session pricing. People interested in the longevity literature who understand the evidence tier they are buying into and want supervision rather than a powder from an anonymous website. And people chasing steadier energy who have already done the responsible thing first.
That last clause matters. Fatigue is a symptom with real, findable causes: anemia, thyroid disease, sleep apnea, depression, and a dozen others that have actual tests and actual treatments. NAD+ is not a substitute for looking, and a clinician who reaches for a wellness injection before basic evaluation is doing it backwards. If your intake suggests an unexplored cause of fatigue, our clinicians will say so, because finding one of those is worth more than any injection we sell.
Safety, plainly
In general terms, injected NAD+ has a manageable and mostly immediate side-effect profile, with one quirk worth knowing before your first dose: speed matters. Given too fast, the injection commonly causes flushing, warmth, chest tightness or a heavy feeling, nausea, or lightheadedness, sensations that typically fade within minutes of finishing. Given slowly, at a conservative starting dose, most people find it manageable. Injection-site soreness, redness, or a small bruise can occur with any injection, and, rarely, allergic reactions can occur, which need immediate care.
This is why supervision is not decoration here. At Parke the protocol starts low, the instructions cover pacing, and your clinician screens your history first, including heart, kidney, and liver conditions, and pregnancy, during which NAD+ is not prescribed. The complete list lives in the important safety information on the NAD+ page; read it before you start, not after.
Supervised dosing vs. drips and powders
If you decide the experiment is worth running, the remaining question is how. The market offers three doors.
The drip lounge. Same molecule, delivered over often two to four hours in a chair, commonly at several hundred dollars per infusion, and the relationship usually ends when the drip does. Nothing about the chair adds evidence; you are paying for ambience and an appointment.
The internet powder or gray-market vial. Cheapest door, worst idea. No clinician screens your history, nobody set your dose, nobody answers when the first injection feels strange, and you are trusting an anonymous seller on sourcing and sterility, for an injectable.
Supervised dosing at home. Our version: a weekly injection of about thirty seconds, started at a deliberately low dose, with pacing instructions, a clinician who screens your history and reviews every refill, and messaging in between, from $199 per month with care included. And the honest caveat travels with it: no route, ours included, has strong human outcome evidence yet. The differences between the doors are cost, time, safety, and honesty, not proof.
What evidence would change the grade
Promising, not proven is a grade, and grades should state their own promotion criteria. Here is what would move ours.
Upgrades: large, well-powered, randomized human trials with pre-registered outcomes that people actually care about, measured energy and function, validated cognitive endpoints, disease outcomes, rather than blood levels alone. Replication of the scattered single positive trials. And trials of the injected route specifically, at doses resembling real protocols. Any of those coming back convincingly positive moves this page, and our sales copy, toward proven.
Downgrades count too. Well-run trials coming back convincingly negative, or credible safety signals emerging, would move the grade the other way, and if it falls far enough, the honest response is to stop offering the treatment. We would rather retire a product than defend one the evidence has turned against.
Either way, we will update this page when the evidence changes. That is a standing commitment, not a figure of speech. If a major trial reads out and this page has not moved, hold us to it.
The bottom line
So, does NAD+ work? The biology works, beyond dispute. The decline with age is documented. Raising blood levels in humans is achievable. And the payoff people are buying, more energy, sharper minds, longer lives, has not yet been demonstrated in the kind of trials that settle such questions, especially for the injected route.
If someone sells you certainty on this molecule, in either direction, they are ahead of the data. What you can buy honestly today is a plausible experiment, run safely, at a fair price, with a clinician who will tell you when to stop. That is what we sell, described exactly. Whether it is worth it to you is a decision we can help you make, and we will respect either answer.
Medical Director at Parke. Board-certified in internal medicine, with a decade of clinical practice focused on metabolic health. She reviews every clinical claim in this journal before it publishes.
- Cleveland Clinic: NAD+ Supplements: Benefits and Risks. A plain-language overview of the molecule, the age-related decline, and why the long-term benefits and risks of supplementation remain unclear.
- Radenkovic D, Reason, Verdin E. Clinical Evidence for Targeting NAD Therapeutically. Pharmaceuticals. 2020. The systematic review of human trials summarized in this article.
This article is general information, not medical advice, and does not create a clinician relationship. Compounded NAD+ is prepared by state-licensed US compounding pharmacies and is not FDA-approved or evaluated by the FDA for safety, effectiveness, or quality. NAD+ has not been shown in rigorous human trials to slow or reverse aging, treat any disease, or produce sustained increases in energy or cognition, and Parke does not market it for those purposes. Treatment decisions are made by a licensed clinician from your intake. Individual results vary and many people notice no effect. Review the important safety information on the NAD+ treatment page.
