how sunscreen works on skin

Sunlight is the main factor causing skin aging and the formation of skin surface spots, even in spring, if you let the sun exposure for ten minutes, the skin will prematurely aging ten days. Only good sun protection, effective prevention of melanin production, sun does not tan, sun does not hurt, in order to always maintain youthful moist.

The role of sunscreen principle

The principle of the role of sunscreen is to isolate the skin from UV rays. You can also get a good idea of what you are looking for in a sunscreen, but do you really know all there is to know about sunscreen? There is no doubt that the concept of sun protection has been recognized by more and more Chinese women, and Vichy did a survey of women in Shanghai in 2003, and as many as 69% of women already use sun protection products in the summer, and on average, they use them six times a week. This year, major brands have launched new products with high sun protection values, even if they only increase the sun protection value of their existing products, which shows the importance attached to the sunscreen market.

Why sun protection

The ultraviolet spectrum in sunlight is in the 100-400nm wavelength range, can be divided into three bands, namely the wavelength of 100-290nm short-wave ultraviolet (UVC), wavelength of 290-320nm medium-wave ultraviolet (UVB) and wavelength of 320-400nm long-wave ultraviolet (UVA). Different wavelengths of UVB penetrate the skin at different depths. uVC is reflected and absorbed by the stratum corneum, and only a small portion penetrates to the superficial layer of the epidermis. UVB is also mostly absorbed by the epidermis, with a small portion reaching the superficial dermis, and is the main wavelength of skin damage. UVA is absorbed by the epidermis, and most of it can penetrate into the dermis and reach the middle of the dermis. 100 times more than UVB reaches the earth's surface at noon in summer, and can penetrate the epidermis to the dermis and cause dermal damage, so it is the main spectrum of ultraviolet disease.

What to protect from the sun

UVA, long-wave UVB, is the main cause of premature aging of the skin, which can penetrate the dermis and cause skin tanning and damage to lipids and collagen, causing photoaging and even skin cancer. UVB zone, medium-wave ultraviolet radiation, which can reach the dermis and make the skin sunburned, causing skin peeling, red spots, tanning and other phenomena, but it can be blocked by glass, sunshades, clothing, etc.

What is "ultraviolet"?

UVB is also called "outdoor ultraviolet radiation", which can be radiated to the ground only by UVA and UVB. UVB, also known as "outdoor UVB", can be isolated with proper cover-up, and is the main cause of skin redness, inflammation and sunburn; UVA will be refracted into the indoor, also known as "indoor UVB", which can penetrate deep into the dermis and will damage collagen, elastic fibers and even fibroblasts, so UVA will not only UVA not only stimulates pigment synthesis and makes the skin "darker", but also causes the main culprit of skin "aging" and fine line generation.

What is the damage of UVA on the skin?

Increases melanin synthesis. It can cause pigmentation, such as dark spots, freckles, chloasma and other kinds of pigmentation to increase, enlarge and deepen. Proliferation of keratin-forming cells and destruction of dermal collagen fibers and elastic fibers. It can lead to skin hypertrophy, sagging, roughness and wrinkle formation.

Capillary dilation, which can produce erythema.

Decreased immune function of the skin. Can form skin cancer or precancerous lesions, such as ray keratosis, squamous cell carcinoma , melanoma, etc. Causes skin diseases. When ultraviolet light acts strongly on the skin, photodermatitis can occur, with erythema, itching, blistering and edema on the skin; in serious cases, it can also cause skin cancer.