Skin is the most easily aging human organs to talk about this topic, let’s start with the aging of trees. The bark of trees is similar to human skin, with the growth of age, external stimuli, the bark gradually thickened, slowly dry, and ultimately cracked, although the age of the tree is not long, but the appearance of the tree has been obviously old. The same is true for the aging of the human body. Of all the organs in the human body, the skin is the one that ages most easily. While other organs are still in their prime, the skin is already wrinkled and showing signs of aging. Because the skin is the body’s protective layer, bear the function of preventing external damage, such as external sand, bacteria, heat, cold, ultraviolet rays will cause damage to the skin. So the stratum corneum of the skin takes up this difficult task without any hesitation. However, when external stimuli come one after another and the protective capacity of the skin’s stratum corneum is insufficient, the skin will be irritated and become red and inflamed, which finally leads to the excessive accumulation of keratin. The appearance of this phenomenon is not only the beginning of skin aging, but also the reason for the grayish appearance of the skin. If the moisturization of the stratum corneum decreases further, the skin becomes flaky and cracked. Of all the irritants, the most threatening to the skin is probably the UV rays. It causes direct damage to the skin and leads to skin aging. The other organs of a person, on the other hand, do not age prematurely because they are shielded from UV rays by the skin. This is the reason why skin ages first among all organs. Although, it is impossible for us to make our skin completely defy the laws of genetic inheritance, we can definitely keep it in the best condition. And this aging can be slowed down by taking care of your skin from the age of 25, as long as you take proper care of it.