NAD+, Nicotinamide Riboside, and Skin Health: What the Latest Research Shows

Key Takeaways

• NAD+ supports cellular energy production, stress responses, and DNA-repair-related processes that are relevant to skin health and aging.
• Recent preclinical and ex vivo studies suggest that nicotinamide riboside (NR) can increase cellular NAD+ and may influence inflammatory signaling, energy metabolism, and responses to UV-related stress.
• NRH also increased NAD+ and affected pathways related to skin homeostasis in early research, but NRH is a distinct compound, so its findings do not necessarily apply to NR.
• The first controlled human studies of standalone topical NR suggest that the tested formulations were well tolerated and may produce short-term improvements in skin hydration and appearance-related measures.
• Most evidence remains preliminary, with much of it derived from cell or ex vivo models; longer-term clinical trials are needed to determine whether topical NR provides meaningful and lasting benefits for skin health and aging.

Skin aging is often discussed in terms of what we can see on the surface: fine lines, wrinkles, uneven tone, dryness, or a loss of firmness. But beneath those visible changes, the skin is constantly carrying out energy-demanding work—maintaining its barrier, repairing damage, responding to UV exposure and other stressors, and renewing its cells. These processes depend in part on nicotinamide adenine dinucleotide (NAD+), a coenzyme involved in cellular energy production and pathways related to stress response and DNA repair. 

The connection between NAD+ and skin health is not new, but the evidence base is beginning to evolve. In an earlier article, we outlined the biological rationale for studying NAD+ and its precursors, such as nicotinamide riboside (NR), in the context of skin aging and reviewed the evidence available at the time. Since then, newly published studies and abstracts have added to the conversation about NR and skin health, offering early insights into its potential effects on skin appearance, barrier-related outcomes, and markers associated with skin aging.

Importantly, much of the earlier human research involving NR evaluated multi-ingredient products, making it difficult to isolate NR’s specific role. Newer research has begun to address that gap, including the first reported controlled human study with topical NR as a standalone ingredient.¹ These studies add to the emerging evidence on topical NR, while questions remain about its potential long-term effects on skin health and whether those effects may vary across individuals.  However, they represent a meaningful evolution in the evidence, moving the field closer to targeted human research and helping clarify the questions future trials will need to answer.

Is NAD+ Important for Skin Health and Aging?

As a coenzyme, NAD+ helps cells produce energy and carry out essential processes involved in cellular maintenance. It also serves as a substrate for enzymes that help cells respond to stress and repair damaged DNA. In the skin, these functions are especially relevant because skin cells continually renew themselves, maintain a protective barrier, and respond to external exposures such as UV radiation. 

NAD+ levels have been shown to decline with age in human skin tissue, with samples from older adults showing lower NAD+ levels, greater oxidative stress, and more DNA damage than those from younger individuals.² Aging itself, as well as UV exposure, inflammation, and other cellular stressors, may place additional demands on NAD+ metabolism in the skin.³ Because skin cells rely on NAD-dependent processes to respond to stress and repair damaged DNA, this provides a biological rationale for investigating NAD+ in relation to skin health and aging, both topically and orally.³

One approach being studied is the use of NAD+ precursors, or compounds that the body can use to produce NAD+. Niacinamide (also called nicotinamide) is a well-known form of vitamin B3 and NAD+ precursor commonly used in topical skincare products. NR is another NAD+ precursor and form of vitamin B3 that has been studied most extensively as an oral supplement, but researchers are increasingly investigating topical applications of NR. For a more detailed discussion of NAD+, skin aging, and earlier evidence, see our previous article.

What Does the Latest Research Say About Nicotinamide Riboside and Skin Health?

The biological roles of NAD+ provide a rationale for studying whether NAD+ precursors could influence skin health.³ However, earlier human research involving NR generally tested it as part of combination products rather than as a standalone active ingredient. Although some of these studies reported favorable changes in skin appearance or other outcomes, their multi-ingredient designs made it difficult to determine whether NR itself contributed to the observed improvements. 

More recently, human research has begun to address this limitation by evaluating topical NR on its own. This is an important step toward more directly assessing NR’s tolerability and potential effects on skin-related outcomes, though the evidence remains preliminary. 

Other recent work has examined how NR or dihydronicotinamide riboside (NRH), a derivative of NR, may affect cellular NAD+ levels, energy metabolism, responses to UV-induced stress, inflammatory signaling, or pathways involved in skin homeostasis. This evidence spans laboratory studies, ex vivo models using human skin tissue, scientific abstracts, and human studies. Each contributes something different: cell and tissue models can help identify potential mechanisms, while well-designed human studies are needed to evaluate safety, tolerability, and meaningful skin-related outcomes.

Preclinical & Ex Vivo Research

Preclinical research includes in vitro experiments conducted in isolated cells, as well as ex vivo studies using human skin tissue maintained outside the body. These models can offer useful mechanistic insights, but they cannot confirm whether the same effects will occur when NR is applied to living human skin.

One recent laboratory study explored how NR may affect inflammatory signaling in skin cells.⁴ Researchers used immortalized human keratinocytes—the main cell type in the outermost layer of the skin—and exposed them to inflammatory cytokines to model certain cellular features associated with atopic dermatitis, also known as eczema. They then treated the cells with NR or nicotinamide mononucleotide (NMN), another NAD+ precursor. In this model, NR increased cellular NAD+ levels and was associated with lower expression of several inflammatory mediators.⁴

These findings offer early evidence that NR can raise NAD+ levels in skin cells and may reduce inflammation. However, because the study was done in cultured cells, it cannot confirm whether the same effects would occur in living human skin—or whether NR could improve eczema, skin inflammation, or other clinical skin outcomes.

A separate scientific abstract investigated whether NR could help restore NAD+ balance during UV-induced metabolic stress.⁵ Researchers evaluated NR in primary human dermal fibroblasts—cells from the deeper layer of skin that help produce and maintain the skin’s structural framework—and keratinocytes, as well as ex vivo human skin explants. In the models tested, NR increased NAD+ levels and was reported to outperform niacinamide in boosting NAD+. In UV-exposed cells, NR restored depleted NAD+, helped preserve cellular ATP levels, and improved cell survival following UV stress. These results were also observed in ex vivo human skin tissue, where NR demonstrated consistent, superior NAD+ boosting efficacy.

These results provide mechanistic evidence that NR may support cellular NAD+ metabolism and energy status under UV-associated stress. However, the work was published as a scientific abstract rather than a full peer-reviewed paper, so the complete methods, results, and limitations are not publicly available. Therefore, the findings should be interpreted as preliminary rather than as evidence that NR can protect human skin from UV damage. 

Another newly published scientific abstract evaluated NRH.⁶ Although NRH is a reduced derivative of NR and is also studied as an NAD+ precursor, it is a distinct compound, so findings involving NRH may not necessarily apply to NR. In primary human fibroblasts and keratinocytes, NRH substantially increased NAD+ levels, reaching higher levels than niacinamide in the tested models. The NAD-boosting effect of NRH was also observed in ex vivo human skin explants, and higher NAD+ in fibroblasts was associated with changes in cellular pathways related to skin homeostasis and cellular aging. 

The authors described NRH as a potent NAD+ booster with potential relevance to skin longevity.⁶ However, because the findings are currently available only in abstract form, further research is needed to clarify NRH’s skin-related effects and how its activity, topical performance, and safety compare with NR.

Clinical Research

The newest human evidence on topical NR comes from a preprint reporting three studies in healthy adults designed to answer a practical sequence of questions:¹ Is topical NR tolerated after one application? Does repeated exposure lead to irritation or sensitization? And can a single topical application change measurable aspects of skin hydration and appearance? This series of studies marks a meaningful shift from earlier skin studies involving NR, which generally assessed it within multi-ingredient products. Here, NR was tested as a standalone active ingredient.  

While the latest research is a preprint, the studies provide the first reported controlled human data on topical NR alone. 

Primary Dermal Irritation Test

The first question was straightforward: could NR remain in contact with the skin for an extended period without causing visible irritation? In this primary dermal irritation test, 30 healthy adults ages 23 to 68 wore patches containing eight different test materials—including NR alone at 50 or 100 mg, NR in a dry-form sachet delivery system (a waterless, powdered formulation of NR packaged in individual sachets), and corresponding vehicle and formulation controls—on separate areas of their backs for 48 hours.  

NR alone produced little to no irritation after this single extended exposure, providing preliminary evidence that the tested NR materials were well-tolerated under the study conditions. In comparison, separate studies have reported irritation with topical nicotinic acid (niacin) and mild redness, itching, or burning with some niacinamide formulations, although niacinamide is generally well tolerated.⁷

Repeated Insult Patch Tests

Once tolerability was established the researchers then conducted repeated insult patch testing in two larger groups: 104 participants using 0.5% NR in water and 106 using 0.5% NR in the dry-form sachet delivery system. 

Participants received nine applications over about three weeks, followed by a two-week break and a final application on previously untreated skin. This final “challenge” application was intended to identify delayed sensitization—an immune response that can contribute to allergic contact dermatitis. 

Neither formulation was associated with evidence of allergic skin sensitization, providing further evidence of NR’s tolerability. 

Acute Skin-Efficacy Trial

The final study shifted from tolerability to the immediate effects of topical NR on several measures of skin appearance and function. The study included 62 healthy Chinese adults ages 18-50 with normal, dry, or combination skin.

Researchers applied a single dose of NR in water, ranging from 0.5% to 10%, to randomized areas of the inner forearm, with water-only sites serving as controls. One group of 31 participants was assessed for moisturizing and smoothing effects, while a separate group of 31 was assessed for measures related to skin protection.

They then measured skin hydration in the stratum corneum—the outermost layer of the epidermis—as well as transepidermal water loss (TEWL), skin hemoglobin as a measure related to redness, and surface smoothness over the following eight hours. 

A single application of topical NR increased moisture in the outermost layer of the skin, with concentrations of 1.5% and higher showing the clearest effects. NR was also associated with improvements in measures of skin redness and surface smoothness, with higher concentrations generally showing the clearest changes.  TEWL decreased in a dose-dependent pattern, although  the change was not statistically significant. Participants also reported perceived improvements in hydration, softness, smoothness, and redness. 

Overall, these findings provide early human data on the short-term effects of topical NR across several measures of skin hydration and appearance.

NAD+, NR, and Skin Health: Current Evidence and Future Research

These studies build on the biological foundation covered in our original NAD+ and skin health article, with preclinical and ex vivo research suggesting that NR can increase cellular NAD+ and influence inflammatory signaling, cellular energy metabolism, and responses to UV-related stress. Research on NRH has also found increased NAD+ and changes in pathways related to skin homeostasis and cellular aging. However, NRH is a distinct compound from NR, and its findings may not necessarily apply to NR. 

The first controlled human studies of standalone topical NR are an essential next step because they begin to assess NR’s tolerability and short-term effects independently of other active ingredients. Early findings suggest that the tested formulations were well tolerated and may improve short-term hydration and appearance-related measures. 

The available evidence includes preclinical, ex vivo, and early human research, with the human studies to date focused primarily on short-term outcomes. Further clinical research will help clarify the longer-term effects of topical NR and its potential role in supporting skin health and aging.  For broader context on NAD+ biology and the earlier research on skin health, see our original article.

References

1. Idoine, R., Amini-Nik, S., Mavoyan, J., Nkrumah-Elie, Y., Diaz, J., & Shioya, E. (2026). Irritation Potential and Acute Efficacy of Topically Applied Niagen® (Niacinamide Riboside Chloride). Preprints, 202603.1657.v1. https://doi.org/10.20944/preprints202603.1657.v1
   
2. Massudi, H., Grant, R., Braidy, N., Guest, J., Farnsworth, B., & Guillemin, G. J. (2012). Age-Associated Changes In Oxidative Stress and NAD+ Metabolism In Human Tissue. PLoS ONE, 7(7), e42357. https://doi.org/10.1371/journal.pone.0042357
   
3. Conlon, N. J. (2022). The Role of NAD+ in Regenerative Medicine. Plastic and Reconstructive Surgery, 150(4 Suppl), 41S-48S. https://doi.org/10.1097/prs.0000000000009673
   
4. Xie, C., Velandia, M. A. M., Marecek, S., Khalil, M., & Hao, J. (2026). Nicotinamide mononucleotide and nicotinamide riboside attenuate cytokine production in human keratinocytes via suppression of p38 Pathway. Molecular Biology Reports, 53(1), 459. https://doi.org/10.1007/s11033-026-11615-2
   
5. Fahim, A., Thorne, M. C., Souza, C. R. de, Rome, C., Chwee, J., & O’Connor, C. (2026). 0785 Nicotinamide riboside (NR) restores NAD+ homeostasis in UV-induced metabolic stress in human skin explants. Journal of Investigative Dermatology, 146(8), S136. https://doi.org/10.1016/j.jid.2026.06.816
   
6. Thorne, M. C., Fahim, A., Souza, C. R. de, Rome, C., Layman, D., Chwee, J., & O’Connor, C. (2026). 0965 Dihydronicotinamide riboside (NRH): A potent NAD+ booster for skin longevity. Journal of Investigative Dermatology, 146(8), S167. https://doi.org/10.1016/j.jid.2026.06.996
   
7. Wohlrab, J., & Kreft, D. (2014). Niacinamide - Mechanisms of Action and Its Topical Use in Dermatology. Skin Pharmacology and Physiology, 27(6), 311–315. https://doi.org/10.1159/000359974