NAD+ Injections: The One on This List That Is Not a Peptide

NAD+ is not a peptide. Nicotinamide adenine dinucleotide is a coenzyme — two nucleotides joined through phosphate groups — and it contains no amino acids at all.

It is sold by the same vendors, reconstituted the same way, and discussed in the same forums, which is why it ends up in peptide conversations. Almost everything distinctive about how it behaves follows from the fact that it is a different class of molecule entirely.

What it actually does

NAD+ is a coenzyme involved in redox reactions across metabolism — it accepts and donates electrons, cycling between NAD+ and NADH. It is also a substrate consumed by enzymes including sirtuins and PARPs, which is where the interest in ageing comes from.

Cellular NAD+ levels decline with age, and that observation drives essentially all of the supplementation interest. Whether raising levels reverses anything associated with the decline is the open question the research is still working on.

Why the amounts are so much larger

This is the most immediately visible difference. Research peptides are dosed in micrograms to low milligrams; NAD+ is discussed in hundreds of milligrams.

A coenzyme consumed stoichiometrically in metabolic reactions is not a signalling molecule binding a receptor at nanomolar concentrations. Different job, different scale.

Injection versus precursors

Most oral NAD+ products are not NAD+ but precursors — nicotinamide riboside or nicotinamide mononucleotide — because the intact molecule is poorly absorbed and is broken down before reaching cells.

Injection is intended to bypass that. What it does not bypass is the question of whether the intact molecule crosses cell membranes efficiently, which is a genuine open point in the literature rather than a settled advantage.

Subcutaneous NAD+ is also widely described as causing flushing, warmth, and injection-site discomfort, which is why intravenous administration in clinical settings is typically given slowly.

The vial math

NAD+ vials are large, and the diluent volumes follow.

Note that a 10 mL reconstitution exceeds a standard 10 mL bacteriostatic water vial once you account for what is already in the vial, and produces far more solution than the 28-day window comfortably allows. The storage guide covers that constraint.

Storage

Storage is the same as any reconstituted vial: 2–8 °C, protected from light, never frozen, and bounded by the shorter of peptide stability and the 28-day limit on bacteriostatic water. The bacteriostatic water guide covers the detail.

Frequently asked questions

Is NAD+ a peptide?

No. It is a dinucleotide coenzyme with no amino acids. It is grouped with peptides by vendors, not by chemistry.

Is injection better than oral NMN or NR?

It bypasses digestive breakdown, which is the argument for it. Whether the intact molecule then reaches the intracellular compartment efficiently is not settled.

Why does it sting?

Flushing and injection-site discomfort are commonly described, which is why clinical intravenous administration is given slowly. It is a reported characteristic rather than a sign something has gone wrong.