Why does skin get tanned by the sun?

The principle of tanning, which is how melanin is formed.

When irradiated by heat or sunlight**, melanocytes located within the basal lamina are excited and activated, and they are present in a 10:1 ratio within the basal cells, which have a dendritic shape and shuttle through the epidermal cells. Melanocytes contain pigment granules, which synthesize melanosomes in the crude endoplasmic reticulum, which catalyzes a series of tyrosine reactions and generates melanin proteins, while tyrosinase will be inactive and act as a transporter to transfer them to keratinocytes.

The more melanin is transferred to keratinocytes, the darker the skin tone. After people of the same skin color are also exposed to the same amount of sunlight, why are some people tanned and some people's ** has not changed much? This has to do with a number of factors.

It mainly depends on how much melanin is produced and how much melanin is transferred to keratinocytes, that is, the more melanin is produced and the more it is transferred to keratinocytes, the darker the skin tone, and vice versa.

Fact 2: The principle of tanning.

I believe that many Asian women are very concerned about skin whitening. There are many whitening products on the market, but how many people really know or understand how melanin is formed? Why do some people tan easily and others don't?

Before you buy whitening products, let's talk about the principle of tanning and understand the truth of the facts.

How is melanin formed?

When irradiated by heat or sunlight**, melanocytes (present in a 10:1 ratio) in the stratum basale are excited and activated, which have the shape of a tree branch and shuttle through the epidermal cells.

Melanosomes are synthesized in the crude endoplasmic reticulum, and tyrosinase, which is located in the Golgi apparatus, will catalyze a series of reactions in the melanocyte and generate melanin protein, while tyrosinase will be inactive and act as a transport to transfer it to keratinocytes. Therefore, the more melanin is transferred to keratinocytes, the darker the skin tone.

People who are afraid of black do not like melanin, however, melanin has its benefits, it has the effect of protecting the body against ultraviolet rays.

When the body is exposed to ultraviolet light, the melanocyte activating enzyme (tyrosinase) accelerates the catalytic action to produce melanin.

For example, two people with different skin tones, after being exposed to the same amount of sunlight for the same time, those with lighter skin tones are prone to redness, for example, we often see foreigners sunbathing, getting red but not tanning. In addition, people with light skin tones are also prone to burns, while people with darker skin tones are less likely to burn.

It can be seen that melanin can block the damage of ultraviolet rays within a certain limit. That is, ** will be red or even black after being exposed to sunlight, which is caused by the accumulation of melanin in the superficial layer of the epidermis.

Excessive sunlight is harmful to the sun and is killing to cells. In order to prevent too much sunlight from penetrating, a large amount of melanin is deposited in the center, so as to prevent the penetration of sunlight into the deep layers to protect the deep tissues.

Why does the sun darken? Let's take a look.

Basking in the sun is only one of the factors that affect whiteness, and other factors that affect whiteness are:

1. The influence of eating habits:

**The internal supplement accounts for 70%, and the external care only accounts for 30%. Internal supplement is to do a good job of eating on the table, and nutrition should be balanced, because the highest level of nutrition is balance, to ensure the sufficient amount of collagen and elastic fiber. Some people often say that the beauty of water means to have good drinking habits.

The absorption of water by human cells is an osmosis method, and only orange slip can be absorbed little by little. Filial piety, so the water should be drunk slowly.

Drink frequently, drink when you are not thirsty, and ensure that you can drink 2500 ml of water every day to provide the body with enough body fluids for the delivery of nutrients and the excretion of waste. In addition, excessive intake of smoking, drinking, coffee, drugs and the top ten junk foods will accelerate the aging of **.

2. The influence of living habits:

Especially to have a good work and rest time, as the saying goes, sleep beauty, to have enough sleep time, adults must ensure seven hours of sleep every day, 10 o'clock at night - 3 o'clock is beauty sleep, during this time of good sleep, your skin will get twice the result with half the effort.

3. The impact of mental stress:

If the pressure from life, work and study is too great, it will lead to the production of free radicals in the body, which will also accelerate the formation of melanin, and will also affect the aging of the body. People with high stress take two ways: one is to exercise properly to help relieve stress, promote blood circulation and cell metabolism; The other is to choose skin care products with anti-free radical ingredients to effectively reduce the signs of facial aging.

4. The influence of time:

It is a natural phenomenon that the metabolism gradually slips from its peak with the passage of time. This requires the choice of skin care products for prevention or repair according to the relationship between ** and age to delay the aging process.

5. Influence of natural phenomena:

Including sunshine, temperature and sandstorm, all affect the ** condition. Choose sunscreen and moisturizers that can help protect your skin from these factors.

6. The impact of environmental pollution:

The chemical floats in the air increase, and it is easy to clog pores and even cause allergies when attached to **. In this case, choose a gentle cleanser to help cleanse the surface without damaging the sebum film and keeping the pores open. At the same time, acne, acne and other ** problems can naturally reduce the chance of occurring.