Studies have shown that the UVA and UVB bands of ultraviolet rays are the main culprits of skin aging, and the decrease in NAD+ levels caused by ultraviolet radiation may be the root cause of skin aging and skin damage.
In August 2021, a research team from Japan published a study in the journal "Photochemistry and Photobiology", showing that supplementing NAD+ precursor molecules such as NMN can protect skin keratinocytes from ultraviolet rays and will help For the prevention and treatment of skin photoaging.
The researchers found that UV radiation activates the enzymes NAMPT and PARP, which produce and consume NAD+, respectively, creating a tug-of-war between cell survival and dysfunction.
NAMPT is a catalytic enzyme that produces NAD+ precursor molecule-NMN. Ultraviolet radiation will activate NAMPT to produce NMN, thereby generating NAD+ and increasing the level of NAD+ in the human body.
The PARP enzyme is essential for DNA repair, which promotes cellular health and survival, but consumes large amounts of NAD+ in the process. UV exposure causes DNA damage, activates PARP, and thus drastically depletes NAD+ levels.
With age, or affected by external factors, when NAD+ synthesis disorder occurs, this balance will gradually be broken. Depletion of NAMPT enzyme levels and depletion of PARP enzymes lead to a sharp drop in NAD+ levels, resulting in UV skin damage, triggering cessation of skin cell proliferation and dysfunction.
To test whether NAMPT could restore UV-induced NAD+ depletion, the researchers applied the NAMPT inhibitor FK866 to UV-irradiated cells and found that it caused severe NAD+ loss and that blocking NAMPT function reduced cell viability by about 35%. These studies suggest that NAMPT plays an important role in maintaining NAD+ levels, keeping skin cells healthy and alive.
Effects of NAMPT on NAD+ level and cells after UV damage
When NAMPT inhibitors are used to block NAD+ production, PARP releases more NAD+. At this time, NMN, the precursor molecule of NAD+, can repair damaged skin cells and help damaged skin cells generate energy and proliferate.
The above studies have shown that NAD+ levels are critical to the health and survival of damaged cells during UV damage and skin aging. The NAD+ supplement NMN can help balance or even increase NAD+ levels and help repair damaged skin cells.