▎ WuXi AppTec content team editor
The skin is the largest organ of the human body and one of the most complex and important organs. It is our first protective barrier that helps protect us from pathogens, ultraviolet rays, chemicals and a variety of harsh environmental damage.
In addition, the skin helps to regulate body temperature and collect sensory information from the surrounding environment, giving us feelings of heat and cold.
As we age, some changes occur in our skin, which also reflects our general health and aging process.
Everyone has a heart for beauty, more and more people pay attention to the state of the skin, and it is particularly important to fight aging. Today, I will share with you some of the content of skin care anti-aging.
Image credit: 123RF
Structure of the skin
Before we can understand how to take care of anti-aging skincare, it is necessary to understand the physiological structure and function of our skin.
As shown in the image below, our skin can be divided into three layers:
Epidermis: the outermost layer of the skin, which can be seen and touched;
Dermis: the middle layer of the skin, which accounts for 90% of the thickness of the skin;
Subcutaneous tissue: the lower layer of the skin, consisting of fat and connective tissue.
▲Cross-section of the physiological structure of the skin. (Image source: References[4])
1
The role of the epidermis
The epidermis is formed by skin cells together with other proteins, and skin cells contain an important protein (keratin), which has the following effects:
Acts as a protective barrier: The epidermis prevents bacteria and viruses from entering the body and bloodstream, as well as the effects of rain, sunlight and other environmental factors.
Metabolism of new skin: The epidermis is constantly making new skin cells. These new cells replace about 40,000 old skin cells that fall off the body every day, and generally metabolize a new layer of skin in 30 days.
Protect the body: Langerhans cells (antigen-presenting cells) in the epidermis are part of humoral immunity that helps fight off bacterial and viral infections.
Formation of skin tone: The epidermis contains melanin, the pigment that gives the skin its color. The amount of melanin determines the color of the skin, hair, and eyes; people who produce more melanin have darker skin and tan faster.
As we age, even if the number of cell layers remains the same, the epidermis will slowly thin and the skin's inherent repair ability will gradually weaken.
2
The role of the dermis
The dermis contains tough connective tissue, hair follicles and sweat glands that do the following:
Contains collagen and elastin: Makes skin cells strong, elastic, and helps restore the shape of the skin.
Hair grows: the roots of the hair follicle are attached to the dermis.
Maintain sensory system health: The neuroreceptors in the dermis give us a sense of touch, pain, and warmth.
Secretion of oil: The sebaceous glands in the dermis help keep the skin soft and smooth, and also prevent the skin from absorbing too much moisture.
Produces sweat: The sweat glands in the dermis release sweat through the pores of the skin, which helps regulate body temperature.
Supply of blood: The blood vessels in the dermis provide nutrients to the epidermis and keep the skin layer healthy.
3
The role of the subcutaneous tissue
The bottom layer of the skin, also known as the fat layer, has the following functions:
Buffers muscles and bones: Fat protects muscles and bones from injury in the event of a fall or accident.
Connecting muscles and bones: Connective tissue in the underlying layer connects the skin layer to muscles and bones.
Helps nerves and blood vessels: Nerves and blood vessels in the dermis layer become larger in the subcutaneous tissue. These nerves and blood vessels branch out, connecting the subcutaneous tissue with the rest of the body.
Regulates body temperature: Fats in subcutaneous tissue regulate body temperature and prevent overcooling or overheating.
Causes of skin aging
As we age, certain changes occur in the skin, and skin aging is one of the most obvious signs of change, including the appearance of wrinkles, sagging skin, age spots, dryness and loss of luster, among others.
This is a complex biological process, influenced by a combination of intrinsic and extrinsic factors. Specifically, intrinsic aging leads to changes in the layers of epithelial cells, while extrinsic aging leads to abnormal accumulation of elastic tissue in the dermis.
Intrinsic factors
Intrinsic factors are caused by a variety of mechanisms:
Excessive production of free radicals: In order to maintain balance in the body, free radicals in the human body are constantly produced and scavenge. As we age, our ability to scavenge free radicals declines, producing excess free radicals that are harmful to the body and lead to aging.
Changes in hormones: aging of the skin is related to the activity of various hormones. Decreased activity of hormones in our bodies, such as estrogen, testosterone, DEHYDRoepiandrosterone, melatonin, insulin and cortisol, can impair skin function, dryness and wrinkles, especially in postmenopausal women.
Damage to mitochondrial DNA: Mitochondria produce energy and therefore constantly produce reactive oxygen species. These reactive oxygen species may cause oxidative stress responses, which can lead to mutations in mitochondrial DNA. Damaged mitochondria can lead to cellular dysfunction, which can lead to aging.
Shortening of telomeres: Telomeres protect chromosomes from degradation and also prevent cellular DNA damage. But if telomeres shorten, they can trigger DNA damage responses, apoptosis, and aging.
External factors
Ultraviolet radiation: About 80% of facial aging is due to sun exposure (photoaging). Photostattered skin can cause skin to lose elasticity, rough and dry skin, irregular pigmentation and deep wrinkles.
Smoking: Smoking destroys collagen and elastin fibers in the dermis layer, making the skin more sagging, hardening and lacking elasticity. Nicotine, carbon monoxide and other toxic substances produced during smoking can cause vasoconstriction and hypoxia on the skin. These can lead to premature aging of the skin.
Lifestyle: such as lack of exercise, alcohol consumption, unhealthy diet, pollution, stress, etc. Maintaining a healthy lifestyle is important for reducing telomere shortening and slowing down aging.
Anti-aging strategies
Beautiful skin is not only an important sign of health, but also one of the ways we promote overall well-being.
In addition to the modifiable external factors mentioned above, some of the main skin care methods will be shared below.
Moisturizer
Studies have pointed out that hyaluronic acid plays a major role in maintaining the hydration and elasticity of the skin. This may be due to the hydration of epidermal cells and an increase in hydroxyproline levels, which contribute to anti-aging.
antioxidant
Preventing photo-aging, using exogenous antioxidants, and other compounds that we can't synthesize in our bodies helps fight aging.
Studies have shown that polyphenols have significant antioxidant properties, which prevent the formation of reactive oxygen species, thereby inhibiting oxidative skin damage.
Vitamins B3, C and E penetrate the skin to form the most important antioxidants. In addition, α lipoic acid, α hydroxy acid, along with vitamins, have also been shown to be beneficial antioxidants.
In a normal diet, regular consumption of foods containing antioxidants (such as vitamins A, C, E, etc.) can reduce the risk of skin damage caused by ultraviolet rays, prevent oxidative stress and enhance DNA repair.
In addition, wearing sunscreen clothing, using a parasol, hiding in the shade as much as possible, and applying sunscreen can also play a role in physical sunscreen.
Sunscreen
The use of sunscreen protects us from UV rays, prevents premature aging, tanning and sunburn, reduces spots on the face, improves skin health and reduces the incidence of skin cancer.
Ultraviolet rays can be segmented by wavelength, and the UVB and UVA bands are the culprits that cause us to sunburn, tanning, and premature skin aging (UVB mainly leads to sunburn, UVA mainly leads to tanning and photoaging).
Different sunscreens have different compositions and different protection against UV rays:
Products containing active minerals (such as titanium dioxide, zinc oxide, etc.) will be deposited on the surface of the skin when applied, forming a protective film that reflects ultraviolet rays to protect the skin from UVB damage;
Some products containing chemical ingredients (such as phthalates, octyl salicylate, etc.) penetrate the skin, breaking down and absorbing UVA that hurts the skin, so that UVA can not reach and damage the dermis layer.
In order to integrate the sense of use and safety of sunscreen, you can choose a combination of materialized sunscreen.
In addition, when buying sunscreen, you need to pay attention to the sun protection factor (SPF).
In simple terms, the SPF value indicates how many times the skin's tolerance to ultraviolet rays has increased compared to the uncoated product after using the sunscreen product, and how many times the sun protection time has been extended.
For example, if a person does not take sun protection measures, the skin begins to be injured after 20 minutes of sun exposure; if you apply SPF 15 sunscreen, under the same sun, it will produce a protection time of 20X15 = 300 minutes, that is, after 300 minutes, the skin will appear sunburn.
It should be noted that the level of SPF determines how long the skin can withstand the sun. It's not that the higher the multiplier, the better the sunscreen, because the higher the SPF value, the greater the burden on the skin. The sun protection coefficient of SPF of about 15 can meet the sun protection needs of daily life.
So what do the different values represent? This means that the protection level (protection rate) of different SPF is different, as shown in the following figure:
SPF 15 provides 93% UVB protection;
SPF 30 provides 97% UVB protection;
SPF 50 provides 98% UVB protection.
▲Sunscreen with sun protection factor (SPF) has a protection rate against ultraviolet rays. (Image source: References[2])
It can be concluded that SPF 30 is only 4% more protective than SPF 15 and SPF 50 is only 5% more protective than SPF 15.
No matter how many times of sunscreen product you choose, it is recommended to apply it several times a day (after applying it, remember to remove makeup at night).
In addition, it is recommended to wash your face with a gentle cleanser in the morning and evening, shower regularly and apply a moisturizing lotion to prevent dry skin. If tanning, sunburn, skin discomfort and other phenomena, it is recommended to go to the dermatologist in time.