NAD+ (nicotinamide adenine dinucleotide)

What is NAD+?

Nicotinamide adenine dinucleotide is a coenzyme present in every living cell. It carries electrons in the reactions that turn food into usable energy, and it is consumed as a substrate by enzymes involved in DNA repair and stress response, including PARPs and sirtuins. It is not a vitamin or an antioxidant in the usual cosmetic sense — it is a metabolic cofactor, which is why its evidence has to be read differently from most skincare ingredients.

Also known as nicotinamide adenine dinucleotide, beta-NAD, DPN. CAS 53-84-9.

What it is used against

• appearance of fine lines
• appearance of elasticity and firmness
• cellular energy metabolism support

Which name means what?

Five similar names describe different molecules. NAD+ is the coenzyme itself, about 663 daltons. Nicotinamide — also called niacinamide, the form you see at 2 to 10% in serums — is a 122-dalton vitamin B3 derivative and a precursor to NAD+, with its own substantial evidence base. Nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) are larger precursors mostly studied orally. Niacin (nicotinic acid) is a different B3 form again. The strong clinical evidence for niacinamide is frequently borrowed to support NAD+ claims; the two are not interchangeable.

The delivery problem, and what encapsulation solves

Three properties work against NAD+ crossing the stratum corneum: roughly 663 daltons, above the widely cited 500-dalton threshold; strongly hydrophilic and charged, which is unfavourable for partitioning into a lipid barrier; and unstable, since extracellular NAD+ is rapidly metabolised.

So in a conventional aqueous serum, NAD+ is a poor candidate to reach living epidermis in useful quantity. If a product claims a topical NAD+ effect, the delivery system is doing the decisive work.

Encapsulation is the direct answer, and it is no longer merely plausible. A 2025 study applied a liposomal NAD+ formulation to ex vivo human skin explants and measured NAD+ in the tissue directly by infrared spectroscopy, finding 30% greater penetration than unencapsulated NAD+ at the same concentration. The same formulation reduced senescent-cell counts by 28.7% in endothelial cells and 15.4% in keratinocytes.

Three things that study does not establish. It tested liposomes, not multi-layer biopolymer encapsulation — the principle carries, the specific performance does not. The 30% is relative to a molecule that penetrates poorly to begin with, with no absolute figure reported. And it used explants from a single donor, ex vivo, over 24 hours.

What does the evidence support?

Exogenous NAD+ does something once it reaches cells: a 2024 study in human fibroblasts found it protective against both UV-induced and intrinsic aging, and identified CD38 — an enzyme that degrades NAD+ — as a limiting factor, with inhibition amplifying the effect.

Clinically, a 2026 case series in 36 patients found topical NAD+ effective and well tolerated in mixed-type melasma over 21 weeks. The important detail is that delivery was microneedling-assisted rather than passive. That supports the penetration argument rather than contradicting it.

For oral precursors the evidence is strongest of all: a placebo-controlled trial found oral NR raised the muscle NAD+ metabolome and lowered inflammatory cytokines, and oral NMN safely raises blood NAD+. Those are systemic endpoints, not skin.

Still unestablished: that passively applied topical NAD+ produces a measured improvement in the appearance of living human skin in a controlled trial at cosmetic use levels. Penetration and clinical benefit are separate claims.

What should you ask of a product?

Which molecule is in it — NAD+, NMN, NR or niacinamide? What keeps it stable, and what is the tested shelf life? What delivery system is claimed, and is there penetration data for that system with that molecule rather than a smaller stand-in? Did the study measure NAD in skin, or consumer perception? Was it independent, and was the product tested as sold?

Is NAD+ safe?

Well tolerated topically at cosmetic levels, with no characteristic irritancy profile and no photosensitising behaviour requiring night-only use. Pregnancy and breastfeeding questions belong with a clinician rather than an ingredient page.

The ratings below use the same vocabulary as the Safety & Stewardship section, so a reader sees one set of terms across the site.

What conditions change the outcome?

Unstable in aqueous formulation; extracellular NAD+ is rapidly metabolised. Requires a stability system and, for any penetration claim, a delivery system with its own data.