Intrinsic and Extrinsic Aging
Intrinsic skin aging is generally thought of as the hereditary, physiological, and immutable form of aging. It is known as the “natural aging process.” No matter how successful or evolved you think you are, you cannot escape intrinsic aging. Who you were born to, and your subsequent individual genetic makeup, cannot at present be altered. Nor can we avoid gravity, the inevitable passage of time, or the fact that we grow older with every solar revolution. For women, fluctuations in hormone levels are implicated: it is well established that decreases in the hormones androgen and estrogen cause collagen degradation, resulting in dryness, dermal atrophy, and loss of elasticity.
When we speak of premature aging, this is usually a reference to extrinsic, or external factors that are controllable to some degree, and often preventable. There can be geographic considerations, like living at high altitude, in New Zealand where there is a big fat hole in the ozone, or in a polluted city. To minimize extrinsic aging we can, for example, keep our delicate visages shaded from the ravaging effects of the sun. We can feed our skin nutrition that keeps it healthy and get plenty of sleep. We can consume antioxidant foods and never, ever smoke cigarettes, even after two martinis. We can be happy. We can learn to not repetitively tense our facial muscles, e.g. frown lines from having a piss-poor attitude, or crows’ feet from squinting.
Since extrinsic aging is the only type we can even minimally control, it makes sense that we would spend some energy 1. Arresting the degradation of skin’s essential building blocks of collagen, elastin, and hyaluronic acid, and 2. Stimulating the synthesis of these proteins and acids in the (desperate) hope of reversing existing damage.