Why does human skin age?

“Everyone desires beauty.” If you want to stay young and beautiful, you have to rely on skin care products. Therefore, people’s demand for skin care products is becoming more and more vigorous. Now it’s 618 again, and it’s time to empty your shopping cart... However, have you chosen the right skin care products?

When it comes to skin care products, we must first understand why our skin ages, because only by knowing the root cause of skin aging can we choose effective skin care products!

01. Why do people age?

This question brings me back to my previous research on aging and longevity. Although we still cannot completely solve the eternal problem of aging and longevity, at least we now have a general understanding of aging.

Our current understanding of aging has become very detailed. For example, the following figure is from a classic review article by a super expert on aging, The Hallmark of Aging [1]. It is also a figure that I like to quote very much. The points summarized in it can be said to be a comprehensive introduction to the current research in the field of aging. Even after several years, our research on aging has not broken through these major frameworks.

Although the picture looks complicated, it is relatively easy to classify certain organ and tissue structures. Taking skin aging as an example, the root causes of skin aging can be summarized into two parts:

1. Damage from multiple blows leads to aging

2. Insufficient repair capacity and stem cell exhaustion.

02. Damage from multiple blows leads to aging

Since life appeared on Earth, we have inevitably suffered from internal and external troubles. Outside, we are affected by various environmental factors. For example, ultraviolet radiation can damage DNA, which is also a common factor in skin aging. In places with strong ultraviolet rays, many people's skin cells have genetic damage. If the damage is difficult to repair and does not enter the cell apoptosis pathway, it will cause the cells to enter aging. In addition, changes in temperature and humidity are also a strong stimulus. As skin exposed to the outside, it is inevitable to deal with the influence of temperature and humidity. These stimuli act on the skin for a long time and are also a factor in skin aging.

Of course, internal factors are also important, a typical example is oxidative stress. Cell metabolism produces high-energy oxygen free radicals, which will constantly collide in cells, causing DNA damage, protein denaturation and many other situations. Although there are corresponding ways in the body, such as superoxide dismutase, long-term attacks will still cause a series of hidden dangers, which will continue to accumulate until the cells are irreversibly aged.

03. Insufficient repair capacity and stem cell failure

In fact, the body is not powerless against damage. In fact, we have corresponding repair mechanisms in our bodies to deal with cell damage. A typical example is the DNA repair mechanism. The gene synthesizes the corresponding repair enzymes and then performs various forms of DNA repair. This is an important achievement that has won two Nobel Prizes.

In addition, when cells cannot be repaired, they will enter the stage of cell apoptosis, degrading and engulfing the entire cell, and then another important cell, stem cells, will differentiate to make up for the apoptotic cells. In fact, this process occurs almost throughout the life cycle, which is why we can maintain a certain body structure for a considerable period of time. However, this system is not unlimited. In fact, as we age, the body's overall repair ability will gradually become unable to cope with our cell damage. What is more troublesome is that the supply of stem cells in the body is not unlimited. As we age, stem cells are also in a state of aging and exhaustion. As a result, repair and supplementation cannot make up for the damage, so cell aging occurs, of course, including skin aging [2].

04. How to deal with skin aging?

Although the overall aging of individuals is still an irreversible process today, and although there are a lot of studies focusing on this and many meaningful molecules and mechanisms have been discovered, with current technology, we still cannot completely curb the aging of individuals.

However, this does not prevent us from using existing means to delay aging to a certain extent, especially in the field of skin. Typical are various anti-aging products, which often contain some anti-aging ingredients that current science has revealed, such as amino acids, coenzymes, nucleic acids, minerals, antioxidants and hyaluronic acid and other anti-aging active ingredients. These ingredients include both cell nutrients, such as amino acids, which can be directly used as nutrition for skin cells, and antioxidants, which are mainly used to deal with the oxidative damage of peroxides to cells and to make up for the lack of antioxidant capacity during cell aging. Hyaluronic acid is a familiar skin protection ingredient used to restore the physiological functions of the skin. These ingredients can slow down the aging of cells to a certain extent by helping to remove oxidative damage and replenishing cell components, which has also been confirmed in research.

Of course, anti-aging does not mean completely solving the problem of skin aging. If you really want to solve the problem of skin aging from the root, I personally prefer to conduct a comprehensive treatment from the stem cell level. After all, for aging skin, the way of patching can only delay aging to a certain extent, but it cannot eradicate the problem. Stem cell recovery is the best strategy. Therefore, in the early days, stem cell nutrients were obtained from embryos and then injected into the skin to provide nutrition and activate stem cells. Now some scientific research institutions are trying to use stem cell therapy to directly solve this problem from the root, but it is still far from application.

In general, skin aging is an objective fact, which in turn affects a person's appearance and image. Therefore, it has always been a key research direction in academia and industry. Some progress has been made, but the effect is limited. In the future, with the further maturity of induced pluripotent stem cell technology and our deepening understanding of skin aging, I believe that overcoming skin aging can be fully achieved in my lifetime.

[1] López-Otín, Carlos, et al. "The hallmarks of aging." Cell 153.6 (2013): 1194-1217.

[2] Goodell, Margaret A., and Thomas A. Rando. "Stem cells and healthy aging." Science 350.6265 (2015): 1199-1204.