On hot summer days, we often hear exclamations: "Why do I turn into 'charcoal-grilled' mode when I bask in the sun, while my friends get a healthy wheat color?" Or what is even more curious is that some people not only do not get dark after sunburning, but ** show an attractive ruddy luster. What exactly is the reason behind this? Is it genetics, or the magic of skincare, or our misconceptions about the sun? 
When our exposure to sunlight, especially ultraviolet (UV) rays, initiates a complex range of biological responses. It's not just a superficial change, it's a deep cellular-level response that determines the color and health of our final appearance. 1.The first dialogue between ultraviolet rays and UVB: defense mechanisms UVA is divided into two types: UVA and UVB, which have different effects on **. UVB is relatively superficial and is mainly responsible for redness and sunburn. And UVA can penetrate deep into the dermis, causing long-term damage such as aging and cancer. In the face of these "invasions", the first line of defense* is the production of melanin. Melanin is a natural protective factor that absorbs and disperses ultraviolet rays, protecting cells under the skin from damage. This process is called the "sun reaction" and is the direct cause of darkening. 2.Genetics: Different people** respond to UV rays very differently depending on your sun protection ability, and this is partly due to genetics. Some people are born with more melanocytes, or these cells are more active, so they are more likely to get darker after sunburning. Some people do the opposite, which explains why different people have different skin tones for the same sun exposure. 3.Ruddy after the sun: Evidence of increased blood flowIn addition to the production of melanin, another factor that affects** color is increased blood flow. When stimulated by UVB, the body increases blood flow to the area to remove heat and repair the damage. This increased blood flow can make the ** look more rosy, which is a natural physiological response, but not everyone will experience a reddening after the sun, which is also related to the individual's constitution and genetic factors. 4.Sun protection: It's not just about avoiding tanning, and after understanding the basic reaction to the sun, it's important to take steps to protect. Proper sun protection can not only avoid sunburn and tanning, but more importantly, reduce the long-term damage of UVA and UVB to the deep structure. Choosing the right sunscreen, shade and wearing protective clothing are the basic sun protection measures that everyone should take. 
For many people, the summer sun seems to be a direct catalyst for skin tone change. What is the science behind tanning? In fact, the occurrence of this phenomenon is not accidental, but the result of the combined effect of genetics and physiological reactions. 1.The secret core of melanin is melanin, which is a pigment produced by melanocytes (or Melanin cells) in **. The main function of melanin is to absorb ultraviolet rays and protect ** from its damage. When ultraviolet rays are irradiated on the **, it prompts melanocytes to accelerate the production of melanin, which is distributed to the surface layer to form a protective umbrella, thus making the ** look darker. As a result, people who tan as soon as they tan usually have a more efficient mechanism for melanin production and distribution. 2.The role of genetic factors: Genes play a decisive role in this process. Scientific studies have shown that the activity and number of melanocytes, as well as the ability to produce melanin, are closely related to an individual's genetic information. In short, if many of your family members get tanned as soon as they get a tan, then you're likely to experience the same phenomenon as well. This is because you inherit genes from your family that produce and distribute melanin efficiently. 3.The effect of ultraviolet raysThe intensity of ultraviolet rays is also an important factor affecting the speed of darkening. UVB rays, especially in the summer or intense sunlight on a beach holiday, quickly stimulate the production of melanin. Therefore, the environment and duration of sun exposure have a direct impact on skin color changes. 4.*Protection StrategyAfter understanding the reasons for tanning, it is particularly important to take appropriate ** protection measures. Using a sunscreen with a high SPF, wearing cover-up clothing and hats, and choosing less sunlight in the morning or evening are all effective sun protection strategies. These measures reduce the direct effects of UV rays on the UV rays, thereby controlling the overproduction of melanin and keeping the complexion stable. When exposed to the sun, there is much more to the changes that occur than just tanning. Some people will experience a noticeable redness after sun exposure, rather than becoming darker. What is the reason behind this phenomenon? Let's do it. 1.Inflammatory response: Immediate feedback of redness after sun is primarily an inflammatory response. When exposed to ultraviolet rays for a long time, especially UVB irradiation, it will cause damage to the surface cells. This injury stimulates self-protective mechanisms, triggering local vasodilation and increased blood flow to promote the repair of damaged cells and the removal of waste products. The dilation of blood vessels in this process results in a ruddy appearance. 2.Individual differences: Genetic and response thresholdsIndividual susceptibility to ultraviolet light varies and is closely linked to genetic factors. Some people have a low threshold for responding to UVs, and even a short period of exposure is enough to trigger an inflammatory response that leads to redness. In addition, people with lighter pigments, such as some whites, are more likely to be red in the sun rather than blackening due to the weaker protective effect of melanin. 
3.Ultraviolet Intensity and Exposure TimeThe intensity of ultraviolet rays and exposure time are also important factors that affect the reaction. When exposed to high-intensity ultraviolet rays, or direct exposure to sunlight without taking protective measures for a long time, the inflammatory response will be more pronounced, resulting in a more pronounced redness. 4.Prevention and care: reduce the phenomenon of rednessAfter understanding the causes of redness after the sun, it is particularly important to take effective prevention and care measures. Using the right sunscreen, especially one that effectively blocks UVA and UVB, is the first step in preventing redness. In addition, using soothing, restorative skincare products, such as those containing aloe vera, after sun exposure can help reduce redness and speed up the return to normal.