Quick Answer
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme found in every cell, where it helps convert food into usable energy and supports enzymes involved in DNA repair and cellular stress response. NAD+ levels decline with age in human tissue.1 NAD+ IV therapy infuses NAD+ slowly over a few hours to raise circulating levels. Most rigorous human evidence so far comes from oral NAD+ precursors like nicotinamide riboside, which reliably raise blood NAD+ and are well tolerated in trials.23 Direct clinical-outcome data on IV NAD+ specifically is still early, so it's best understood as a supportive longevity tool rather than a treatment for any condition. At Defiant in Lisle, NAD+ is offered as both an IV infusion and a subcutaneous injection, with pricing and protocol set at your consultation.
NAD+ IV therapy delivers a coenzyme your cells already run on, directly into your bloodstream through a slow drip. The idea behind it is simple even if the biology isn't: NAD+ is central to how your cells make energy, and levels appear to drop as we age. What people want to know is whether topping it up through an IV actually does anything you can feel, and that's where the honest answer gets more interesting than most clinics will admit.
Here's what the research actually shows, what NAD+ may and may not support, and what a session looks like at Defiant in Lisle.
What NAD+ Actually Is
NAD+ is a coenzyme your cells can't function without. The full name is nicotinamide adenine dinucleotide, and it shows up in every cell in your body. Think of it as a shuttle that carries electrons around during metabolism, which is a big part of how your mitochondria turn the food you eat into the energy your cells run on.
It does more than power metabolism, though. NAD+ is also the fuel for a family of enzymes called sirtuins, along with the PARP enzymes that help repair damaged DNA. Every time one of those enzymes does its job, it uses up a little NAD+, so your body is constantly making it and spending it. When researchers talk about NAD+ being tied to aging and cellular health, this is the machinery they mean: energy production, DNA repair, and how cells respond to stress all lean on having enough of it around.
Why NAD+ Declines With Age
NAD+ levels appear to fall as we get older. In one well-cited study, researchers measured NAD+ in human skin tissue across a wide age range and found a strong negative correlation between NAD+ levels and age in both men and women.1 Older tissue simply had less of it.
The likely reason is a mix of making less and burning more. As oxidative stress and DNA damage accumulate over the years, the PARP repair enzymes work overtime, and every repair job spends NAD+. So you end up with rising demand meeting a slower supply. That decline is one of the reasons NAD+ has become such a popular target in longevity research, and it's the whole rationale behind trying to raise levels back up, whether through an IV, an injection, or an oral precursor.
What NAD+ Therapy May Support
This is where it pays to be straight with you, because the marketing around NAD+ has gotten well ahead of the science.
The strongest human evidence isn't for IV NAD+ at all. It's for oral precursors, the raw materials your body converts into NAD+. In the first human trial of nicotinamide riboside, single doses of 100, 300, and 1,000 mg produced dose-dependent increases in blood NAD+, which showed that taking a precursor by mouth genuinely moves the needle on circulating levels.2 A later placebo-controlled trial in 24 healthy adults aged 55 to 79 found that 1,000 mg of nicotinamide riboside a day for six weeks raised NAD+ by roughly 60% and was well tolerated, with a signal that it may support healthier blood pressure and arterial stiffness in participants who started with elevated readings.3 Those are real, measured results, and they're why raising NAD+ is taken seriously as a goal.
Intravenous NAD+ is a different story. The human data is thinner. A pilot study infused 750 mg of NAD+ over six hours in eight participants and tracked how it moved through the blood and urine, and one finding is worth knowing before you book: NAD+ didn't rise measurably in the bloodstream until after about two hours of infusing.4 Your body appears to process it gradually rather than flooding your cells the moment the drip starts, which is part of why NAD+ IV sessions run long.
So what may it support? Research suggests raising NAD+ may support cellular energy metabolism and the enzymes involved in DNA repair, and many clients report feeling more mentally clear or energized after a series of sessions. That's an honest framing. What NAD+ therapy is not is a proven treatment for aging, addiction, neurodegenerative disease, or any specific medical condition. The clinical trials that would settle those questions mostly haven't been done yet, and any clinic promising otherwise is getting ahead of the evidence.
IV or Injection: How the Two Compare
Defiant offers NAD+ two ways, and they suit different people. The IV infusion delivers a larger dose through a slow drip and tends to be the choice when someone wants a bigger single session. The subcutaneous injection is faster, lower-commitment, and easier to fit into a regular routine, which makes it a practical way to keep NAD+ topped up between IVs or on its own.
| NAD+ IV infusion | NAD+ injection | |
|---|---|---|
| How it's given | Slow drip into a vein | Small shot under the skin |
| Session length | Longer (often 1 to several hours) | A few minutes |
| Typical dose | Larger per session | Smaller, more frequent |
| Best for | A bigger single top-up | Convenience and maintenance |
| Pricing at Defiant | Set in-clinic | Trial 50 mg $50, 100 mg $95, 10-shot vial $355 |
If you're weighing one against the other, we go deeper on the trade-offs in our guide comparing NAD+ injection versus IV delivery. The short version: neither is universally better, and the right pick depends on your goals, your schedule, and your budget.
What to Expect in a Session at Defiant
A NAD+ IV at Defiant starts with a consultation so a provider can review your goals and health history before anything is infused. NAD+ IVs run slow on purpose. Pushed too fast, NAD+ can bring on flushing, a tight or cramping feeling in the chest, or mild nausea, and slowing the drip usually settles it. So plan to be comfortable for a while, bring something to read or watch, and let the team pace the infusion to how you feel.
You don't have to start with a full IV. The subcutaneous injection is a low-commitment way to try NAD+ first, and if you'd rather stay oral, our IV therapy and vitamin shots menu includes Niagen Longevity+, a nicotinamide riboside shot that uses the same precursor studied in those human trials. Everything runs out of our Lisle clinic, and we see clients from Naperville, Downers Grove, Wheaton, and across Chicago's western suburbs.
Who NAD+ Therapy Is For
NAD+ therapy tends to draw two kinds of people. The first is the performance-minded crowd who are already dialing in training, recovery, and sleep, and who see NAD+ as one more lever in a longevity routine that might also include peptides, HBOT, or contrast therapy. The second is adults in their 40s, 50s, and beyond who feel their energy and recovery aren't what they were and want a supportive option that's grounded in real biology.
It's worth saying who it isn't for. If you're pregnant, breastfeeding, or managing a significant medical condition, NAD+ therapy may not be appropriate, which is exactly why every protocol starts with a provider consult rather than a walk-up drip. NAD+ works best as one piece of a broader plan, not a standalone fix, and we'll tell you honestly if we don't think it's the right fit.
- NAD+ is a coenzyme in every cell that supports energy metabolism, DNA repair, and cellular stress response, and its levels decline with age in human tissue.1
- The strongest human evidence is for oral NAD+ precursors like nicotinamide riboside, which reliably raise blood NAD+ and are well tolerated in trials.23
- Direct clinical-outcome evidence for IV NAD+ is still early; a pilot study showed IV NAD+ raises blood levels gradually, not instantly.4
- NAD+ therapy is best understood as a supportive longevity tool, not a proven treatment for any medical condition.
- Defiant offers NAD+ as both an IV infusion and a subcutaneous injection in Lisle, serving Naperville, Downers Grove, Wheaton, and Chicago's western suburbs.
Frequently Asked Questions
Is NAD+ Right for You?
Curious whether NAD+ fits your longevity routine? A provider reviews your goals and health history and builds a protocol around them, IV or injection. The consultation is where you find out.
Keep Reading
Last updated August 12, 2026.
References
- Massudi H, Grant R, Braidy N, et al. Age-Associated Changes in Oxidative Stress and NAD+ Metabolism in Human Tissue. PLoS ONE. 2012;7(7):e42357. PLoS ONE
- Trammell SAJ, Schmidt MS, Weidemann BJ, et al. Nicotinamide riboside is uniquely and orally bioavailable in mice and humans. Nature Communications. 2016;7:12948. Nature Communications
- Martens CR, Denman BA, Mazzo MR, et al. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults. Nature Communications. 2018;9:1286. Nature Communications
- Grant R, Berg J, Mestayer R, et al. A Pilot Study Investigating Changes in the Human Plasma and Urine NAD+ Metabolome During a 6 Hour Intravenous Infusion of NAD+. Frontiers in Aging Neuroscience. 2019;11:257. Frontiers in Aging Neuroscience