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What NAD+ is, and why it fades
Longevity has become a loud conversation. Underneath the noise sits one molecule that genuinely matters, and it is worth understanding on its own terms rather than through the marketing built on top of it.
What it actually does
NAD+, or nicotinamide adenine dinucleotide, sits in every cell in your body. Its job is not exotic. It is the molecule that carries electrons through the process that turns food into usable energy, and without it that process stops. It is also the fuel for two families of enzymes involved in DNA repair and cellular maintenance, the PARPs and the sirtuins, which is why it keeps appearing in ageing research.
That is the honest description. Not a youth molecule. A coenzyme your metabolism cannot run without.
The part the category oversells
You will read everywhere that NAD+ collapses with age. The real picture is more interesting than that.
Where researchers have measured NAD+ directly in human tissue, the decline is real. A study of non-sun-exposed skin from donors aged newborn to 77 found NAD+ correlated negatively with age in both men and women [1]. Imaging studies of brain and muscle point the same way.
Blood is where it gets complicated. Results across studies disagree, and a 2025 review in Nature Metabolism concluded that consistent evidence for an age-related decline in humans comes from a limited number of studies, and that clinical trials of NAD+ precursors have so far shown limited efficacy [2].
So the fair statement is this. NAD+ appears to fall in several tissues as we age. The size of that fall, whether it is uniform across the body, and how much of it a supplement can address are all still open. Anyone telling you otherwise is selling something.
Why you cannot simply take NAD+
Here is where it gets practical, and it connects to something we covered in an earlier piece.
Skin lets small molecules through. The rule of thumb is roughly 500 daltons. NAD+ weighs about 663, which puts it on the wrong side of that line, and it fares badly through digestion too. This is not a formulation preference. It is the reason NAD+ is delivered as precursors rather than as itself.
NMN, nicotinamide mononucleotide, weighs about 334. Resveratrol is around 228. NAC is smaller still. These are molecules the skin will pass.
What the precursor research shows
Oral NMN has been through several controlled trials. A 2023 study of 80 middle-aged adults found blood NAD+ rose in a dose-dependent way across 300, 600 and 900mg daily, alongside improvements in six-minute walk distance [3]. A 2024 trial in older adults raised blood NAD+ but missed its primary endpoint, finding its walking result only on a secondary measure [4].
That is a genuinely promising body of work at an early stage, and we would rather describe it that way than round it up.
Resveratrol and NAC sit alongside it for adjacent reasons. Resveratrol was first studied as an activator of the sirtuins, the same NAD+ consuming enzymes described above, though the mechanism has been argued over since. NAC is a precursor to glutathione, the body’s own principal antioxidant.
Where we stand
NAD+ science is real, unfinished, and worth following closely. What we will not do is pretend the questions are settled in order to sell you something.
It is also why our NAD+ Longevity patch delivers NMN, resveratrol and NAC, the precursors the skin can actually pass, rather than NAD+ itself.
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Frequently asked questions
What is NAD+ and why does it matter?
NAD+ is a coenzyme found in every cell, where it helps turn food into usable energy and supports the enzymes involved in DNA repair and cellular maintenance. Research suggests NAD+ declines in several tissues as we age, though the full picture is still being worked out. Our NAD+ Longevity patch delivers NMN, resveratrol and NAC, the precursors the body uses in NAD+ metabolism, through the skin.
How is a patch different from taking NAD+ another way?
NAD+ itself is too large a molecule to cross the skin readily, and it fares poorly through digestion, which is why it is delivered as smaller precursor compounds rather than as NAD+ directly. The patch releases those precursors steadily through the skin over eight hours, bypassing the digestive system - no needles, no timing around meals, and no peaks and crashes.
How do the patches work?
Each patch releases its ingredients through the skin over around eight hours, into circulation rather than through the gut. That means steadier delivery, no reliance on swallowing capsules, and none of the digestive breakdown that reduces how much of an oral dose actually reaches you.
How long does it take to work?
As with any supplement, the meaningful benefits come from consistent daily use over weeks rather than from a single application. Individual responses vary.