One of the most important mechanisms contributing to senescence is oxidative stress – 'the free radical theory of aging'. It is well known that NAD levels decline with age. There is a rapid decline in most individuals from around the age of 40 onwards. This decline is associated with reduced energy production, increasing DNA damage and cell death as well as increased prevalence of disease. It seems reasonable to suggest that replenishing the body's stores of NAD may alleviate these features of the aging process. Whilst there is as yet no definitive evidence that this will occur in humans there is mounting experimental evidence of beneficial effects in animal studies.
Sun damage occurs as a result of the skin's exposure to ultraviolet (UV) rays. As UV rays are absorbed, they can cause cells to enter into photo-excited states. They can also produce changes or mutations in the DNA within the skin cells, causing the cells to function, look, and act differently than normal cells.
If the skin is continually abused, over time it struggles with self-repair and the signs of sun damage begin to emerge. As the cells within the basal layer begin cellular replication and keratinization, the DNA changes caused by the sun's UV rays are copied into new cells. Eventually, visual changes on the skin's surface appear such as hyperpigmentation, uneven skin tone, fine lines and wrinkles, and other more serious imperfections such as actinic keratosis (precancerous lesions).
Fortunately, the body has mechanisms to repair damaged DNA, as it is essential to maintaining genomic integrity and immune function. NAD+ is one of the components of that process. NAD+ also stimulates energy metabolism and thereby enhances epidermal renewal and dermal functions, all of which result in healthier skin. Sun exposure is currently responsible for more than 90% of all skin cancers. Promoting healthy skin that can protect and repair itself as well as using proper protection against the sun and avoiding sun exposure when possible is absolutely necessary to reducing the effects of long-term sun damage to the skin.