What are the effects of NAD+ on skin aging?

The aging of the skin results from a combination of intrinsic and extrinsic factors. Among the internal causes, we find the shortening of telomeres and mutations of mitochondrial DNA, often exacerbated by oxidative stress induced by the free radicals. External factors, such as exposure to UV rays and pollution, accentuate these mechanisms. This results in visible signs, such as wrinkles, skin dryness, and the appearance of pigmented spots. Hormonal fluctuations, especially in women, also play a key role in the progression of this process.

A central element in this process is the gradual decrease in NAD+ levels, a coenzyme essential for cellular function. NAD+ is involved in many biological processes, such as energy production, DNA repair, and defense against oxidative stress. This decline in NAD+ contributes to the degradation of skin cells, causing a loss of elasticity, wrinkles, and a less radiant complexion.

Armed with this understanding of the fundamental role of NAD+, it is now being studied for its potential benefits in cosmetics. However, while the biological mechanisms of NAD+ are well documented, scientific evidence remains limited regarding its specific effectiveness in topical application. It is therefore important to distinguish the data supporting the use of NAD+ in cellular regeneration from the lack of consensus on its direct effects when applied locally to the skin. Nevertheless, despite the lack of conclusive studies, NAD+ appears to possess interesting properties that could slow down the skin aging process.

• NAD+ and its potential as an anti-inflammatory agent.

  Chronic inflammation plays a crucial role in the onset of aging signs by promoting the degradation of collagen and elastin fibers, which are essential for skin firmness and elasticity. Additionally, it increases the production of free radicals, thereby exacerbating oxidative stress, and disrupts DNA repair mechanisms.

  However, a study conducted among 10 women aged 21 to 61 suffering from rosacea showed that a cream containing 1% NADH significantly reduced inflammation in just two weeks. Although these results are preliminary, they suggest that NADH could help soothe chronic inflammation and slow the appearance of visible signs related to skin aging.

  These findings suggest a potential for NAD+ and its derivatives, not only to enhance skin quality, but also to act on various aspects of age-related cellular decline. Nevertheless, more rigorous studies are necessary to confirm these effects and explore the exact mechanisms at work.

• NAD+ and Cellular Energy Production.

  NAD+ is crucial for the production of ATP, the primary energy source for cells. This production takes place in the mitochondria, where NAD+ is involved in essential enzymatic reactions. Studies have shown that aging often comes with a decrease in NAD+ levels, which results in a drop in energy production and a reduction in cellular functionality. This decrease in available energy can cause a deterioration of skin cells, resulting in a loss of elasticity, wrinkles, and a dull complexion.

• SIRT1 and NAD+: An approach to slow down skin aging and improve cellular function.

  Sirtuins constitute a family of enzymes that rely on NAD+ to function and are involved in numerous biological processes, such as DNA repair, inflammation reduction, and metabolism regulation. Studies on human endothelial cells have shown that the inhibition of SIRT1 leads to premature aging of these cells.

  This phenomenon is linked to an increase in the acetylation of the p53 protein and imbalances in the expression of key genes such as PAI-1 (Plasminogen Activator Inhibitor-1) and eNOS (Endothelial Nitric Oxide Synthase). These findings underscore the importance of SIRT1 in preventing premature cellular aging and maintaining optimal vascular function. This reinforces the idea that sirtuins, activated by NAD+, play a crucial role in protecting cells from the effects of aging, beyond the skin, by affecting other vital systems.

  In parallel, SIRT1 is particularly studied for its impact on protection against skin aging. According to recent research, this enzyme could also influence longevity by acting on the brain, specifically in the dorsomedial and lateral nuclei of the hypothalamus. A study has highlighted the role of SIRT1/Ox2r signaling in slowing down aging-related processes and extending lifespan, showing that SIRT1 could have protective effects well beyond the skin. In conclusion, these studies confirm that SIRT1, through its action on various biological systems, represents a promising target for slowing down aging and maintaining cellular function, particularly through its activation by NAD+.

• NAD against oxidative stress related to aging.

  Oxidative stress, caused by the accumulation of free radicals, is one of the main factors of skin aging. However, NAD+ could play a key role in the skin's antioxidant defense by supporting the levels of other antioxidants, such as glutathione. A recent study conducted on cells derived from the rat adrenal medulla showed that the addition of NAD+ could increase the antioxidant capacity of cells by promoting a better balance between reduced glutathione (GSH) and oxidized glutathione (GSSG), and total glutathione.

  In parallel, a study on mice revealed that the administration of NAD+ reduces skin damage induced by UVC radiation. These effects include a decrease in oxidative stress, inflammation, DNA damage, and apoptosis. Additionally, another study on human keratinocytes irradiated by UVA and UVB rays showed that the activation of the NAD+ recovery pathway, via NAMPT, protects against proliferation defects induced by UV radiation. These findings support the idea that NAD+ could act as a powerful protector against skin damage and visible signs of aging.

• NAD+ and Cellular Regeneration.

  NAD+ is essential for the process of cell regeneration, particularly for skin cells. When the skin is damaged, this coenzyme activates mechanisms that repair DNA, thereby allowing the affected cells to recover and promote the growth of new healthy cells. Recent studies have revealed that NAD+ levels decrease with age, which can slow down skin repair.

  For instance, research has shown that the reduction of NAD+ in the epidermis, due to a decrease in the activity of the regulator Pgc-1α, results in slower healing and reduced cell proliferation. Conversely, restoring these levels can speed up the healing process, demonstrating the importance of this molecule in maintaining skin health.

  Furthermore, additional research suggests that NAD+ could play a crucial role in the regeneration of dermal fibroblasts, the cells responsible for the production of collagen and elastin. By enhancing their repair capacity and supporting their activity, NAD+ could thus contribute to maintaining skin elasticity and preventing the onset of wrinkles, preserving its integrity and firmness over time.

NAD+ could potentially be a solution for maintaining youthful and healthy skin. By acting on the front lines of cellular energy, DNA repair, and defense against oxidative stress, NAD+ appears to be a promising agent to counteract skin aging, but its topical application has been minimally studied to date.