The next generation of skin longevity will depend on delivery — not just ingredients
NAD⁺ has become one of the most talked-about molecules in longevity science. It is essential to cellular energy, DNA repair, mitochondrial function and many of the biological processes associated with healthy ageing.
As NAD⁺ levels decline with age and UV exposure places repeated stress on the skin, it is not surprising that NAD⁺ precursors such as nicotinamide mononucleotide, NMN, nicotinamide riboside, NR, and nicotinamide, NAM, are attracting growing interest in skincare.
But topical skincare has a problem that oral supplementation does not.
Before any active ingredient can support the viable epidermis, it first has to cross the skin’s outer barrier: the stratum corneum.
That means the real question for topical NAD⁺ skincare is not simply:
Which NAD⁺ precursor has the most exciting biology?
It is:
Which NAD⁺ precursor can actually reach the target site in the skin, at meaningful concentrations, for long enough to make a difference?
At Limeway Pharma Design, this is the question at the heart of our topical NAD⁺ precursor technology.
The problem with translating oral NAD⁺ science into topical skincare
NMN and NR have attracted considerable attention as oral NAD⁺ precursors. They are often positioned as newer, more advanced routes into NAD⁺ biology.
That narrative may be relevant for systemic supplementation, but topical application is different.
A molecule applied to the skin has to pass through the stratum corneum, a highly effective lipid barrier designed to keep external substances out. This barrier is particularly challenging for highly polar, water-soluble molecules.
NMN is a highly polar molecule. Although it has compelling biological interest as an NAD⁺ precursor, its ability to permeate human skin in meaningful quantities remains uncertain. Predictive skin permeation modelling suggests that NMN may be around 100-fold less permeable than nicotinamide/NAM. Current literature also appears to lack direct in vitro human skin permeation studies demonstrating effective NMN delivery into the viable epidermis.
This matters because a topical ingredient cannot deliver skin benefits simply by being present in a cream. It must be delivered.
Stability is another important issue
There is also a formulation challenge.
NMN is known to degrade through pathways that can eventually produce nicotinamide/NAM and ribose. Recent analysis of NMN-containing cosmetic products found very low or undetectable NMN content in several tested products, suggesting significant degradation may occur in some commercial formulations.
Even when NMN degrades into NAM, that does not automatically establish efficacy. In topical dermatology, the amount of active ingredient applied to the skin is only part of the story. The more important question is how much reaches the target site, in what form, and for how long.
This is why formulation design is critical.
Why nicotinamide/NAM remains highly relevant
Nicotinamide, also known as niacinamide or NAM, is a well-established dermatological and cosmetic active. It has a long history of topical use and is associated with benefits including barrier support, reduced inflammation, improved pigmentation and healthier skin appearance.
NAM also has a practical advantage: it is smaller and better suited to passive diffusion through the stratum corneum than highly polar NAD⁺ precursors such as NMN.
For this reason, NAM may be less fashionable than NMN, but it may be more useful for topical NAD⁺ skincare — provided it is delivered correctly.
Limeway’s focus: sustained epidermal delivery
Limeway’s technology is not simply based on adding NAM to a cream.
Our focus is sustained delivery.
The Limeway glycol-in-silicone co-enhancer platform has been designed to help deliver nicotinamide into the epidermis over a prolonged period. The platform integrates pharmaceutical delivery science with cosmetic elegance, aiming to overcome some of the long-standing limitations of topical products: poor penetration, irritation, poor user experience and poor adherence.
The technology uses principles including co-enhancer design, non-volatile residual phase behaviour and carefully selected low-solvency silicone emollients to help maintain delivery performance after the product is applied to the skin.
This is important because NAD⁺ biology is not a momentary event. Skin exposed to ageing and UV damage may benefit from sustained support of cellular energy and repair pathways.
From skin ageing to skin longevity
The concept of skin longevity goes beyond short-term cosmetic improvement.
It recognises that visible ageing, UV damage, barrier dysfunction, pigmentation changes, inflammation and pre-cancerous field damage are biologically connected. Many of these processes involve cellular energy, DNA repair, mitochondrial function, immune resilience and epidermal renewal.
NAD⁺ sits at the centre of many of these pathways.
That is why topical NAD⁺ precursor therapy is such an exciting area. However, the promise of this category will depend on products that can deliver the right precursor to the right skin compartment, at the right concentration, for the right duration.
For Limeway, this points strongly toward NAM as the preferred topical NAD⁺ precursor.
The future of topical NAD⁺ skincare
The skincare market often moves quickly toward the newest ingredient story. NMN and NR have brought important attention to NAD⁺ biology, and that has helped open up a valuable conversation about skin ageing and cellular energy.
But for topical skincare, the deciding factor may not be novelty.
It may be delivery.
NAM has an established dermatological history, a more favourable topical delivery profile, and a clear role as a precursor within NAD⁺ biology. When combined with advanced formulation technology, it offers a practical and scientifically grounded route toward topical skin longevity.
The future of NAD⁺ skincare may not belong to the newest molecule.
It may belong to the molecule that can actually get to where it needs to work.