Comparison
NAD vs NMN: which one should you actually take?
Why you cannot efficiently swallow NAD+ itself, what NMN does differently, and what the FDA's September 2025 reversal changed for buyers.
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The Journal
Fresh from the lab.
Comparisons, format breakdowns, protocol notes and the underlying science of the NAD⁺ precursor space.
Comparison
NMN vs NR: two precursors, no clear winner
Both feed the same salvage pathway. The honest bottom line is that no substantial head-to-head human trial exists — and what to decide on instead.
Compare the precursors
Comparison
Oral vs IV: the comparison most people get backwards
Infusion wins on bioavailability and loses on cost, time and practicality. Which of those actually matters depends on a question most buyers skip.
Weigh the routes
Science
Why NAD+ declines with age
It is mostly not a production problem. PARPs, sirtuins and CD38 explain where it goes — and why that changes what a precursor can realistically do.
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Protocol
When to take your dose: timing, food, and what matters
Morning dosing has a real circadian rationale. The with-or-without-food debate mostly does not. A protocol you can actually sustain.
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Format
Oral capsules: the unglamorous default that usually wins
Capsules lose a lot of the dose to digestion and the liver, and still beat every other format for most people. The reason is adherence.
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Format
Injectable NAD+: the at-home middle ground
Subcutaneous injection skips digestion the way an infusion does, without the clinic chair. How the prescription route works and who it suits.
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Format
IV infusion: complete delivery, impractical habit
What an appointment actually involves, why sessions run for hours, and when the clinic route is worth its cost over the alternatives.
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Format
Sublingual NAD+: a real mechanism, oversold
Under-the-tongue delivery genuinely skips the liver — for the fraction that crosses. Why that fraction is smaller than the marketing implies.
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Format
Nasal spray NAD+: a real pathway, unproven for this
Nose-to-brain delivery is a legitimate research area. Whether NAD+ precursors actually use it is a separate question, and the answer is not yet.
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Format
Transdermal patches: the one format to skip
Too large, too water-soluble, and needed in doses far too high. This one fails on chemistry, not on manufacturer quality.
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Category
Research-grade NAD+: what "research use only" actually means
Vials sold at a fraction of consumer pricing, on the explicit basis that they are not for human use. What the price gap is actually buying.
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Comparison
NAD vs NR: why this one is not a close call
The third leg of the comparison triangle. A small uncharged precursor against a molecule that gets dismantled before it is absorbed.
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Science
CD38: the drain that grows with age
The dominant consumer of NAD+, rising with inflammation. Why that reframes the decline — and limits what a precursor can do about it.
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Science
Sirtuins and the NAD+ dependency
They consume NAD+ rather than borrowing it, which is the real mechanistic case for precursors. And where the resveratrol story got ahead of the evidence.
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Science
Can you actually measure your NAD+?
The molecule degrades after collection, blood may not reflect tissue, and there is no reference range. What a number can and cannot tell you.
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Protocol
How long to trial it before judging
Most people decide during exactly the window in which they are least able to tell. A ninety-day method that costs nothing to run.
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Protocol
What to stack with NAD+, and what to skip
The methylation argument is the strongest addition. Resveratrol and CD38-inhibitor flavonoids are weaker than they look.
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Not sure where to start? The format finder is four questions and points you at the page most likely to be relevant to your situation. Or start with NAD vs NMN, which is the question most people arrive with.