At present, the whitening cabin used in major beauty institutions only makes use of the photochemical effect of LED red light and the characteristics of titanium dioxide. It is not the cutting-edge "black technology" marketed by businesses, and its whitening effect is very limited. —— Li Jing, director and chief physician of Medical Cosmetology Department of Affiliated Hospital of Tianjin Institute of traditional Chinese Medicine As the saying goes, a white cover a hundred ugly, the sun is not as strong in winter as in summer, which is a good opportunity for whitening. Recently, following the whitening needle, the whitening cabin has poured into the public's view under the crazy "Amway" of the "little red book" blogger, "lying white" no longer seems to be a dream. However, is this whitening method really reliable? In this regard, Li Jing, director and chief physician of the medical cosmetology department of the Affiliated Hospital of Tianjin Institute of traditional Chinese medicine, made it clear in an interview with the reporter of science and Technology Daily that the whitening cabin currently used in major beauty institutions only makes use of the photochemical effect of LED red light and the characteristics of titanium dioxide, which is not the cutting-edge "black technology" marketed by businesses, and its whitening effect is very limited. LED red light has photochemical effect on skin At first glance, the whitening cabin gives people a sense of science and technology. The process of whitening cabin services provided by most beauty agencies is roughly as follows: cleaning the customer's body surface, applying whitening products, entering the cabin for irradiation for 20 minutes, and finally cleaning the body surface residues. The legendary "black technology" cabin is actually filled with LED red light tubes with a wavelength of 600-700 nm. Merchants claim that the principle of Meibai cabin is to use cold light 655 nm light source with whitening agent to stimulate blood circulation through light wave, accelerate epidermal melanin metabolism, inhibit melanocyte production, and achieve the effect of whitening and rejuvenation. "LED is a light-emitting diode, which is a very common light-emitting device in our daily life. Clinically, it is often said that red, blue and red yellow light are used to treat acne." Li Jing introduced that led is a cold light source. Through irradiation, it will produce photochemical effect on our skin, not photothermal effect. Some foreign scholars believe that mitochondria absorb the most red light in human cells. LED red light irradiation can increase the catalase activity of mitochondria and enhance the metabolism of human cells. At the same time, it will also increase the content of glycogen and promote the synthesis of cells and collagen. LED red light has a wide range of clinical applications in dermatology and other disciplines. In dermatology, LED red light can be used for anti-inflammatory and pain relief of inflammatory rashes such as pustules, nodules and cysts, and also plays a certain role in the dilution of acne marks and pits in the later stage of acne. In addition to dermatology, LED red light can also be used to accelerate the healing of wounds and ulcers and promote hair growth. Orthopedics can also use it to promote the healing of bone injuries. Neurology uses it to repair nerve injuries. At the same time, it can also increase the phagocytosis of white blood cells, increase the immunity of the body and accelerate wound repair. Hidden secret of fast "whitening" in whitening cabin At present, LED red light is commonly used in the clinical treatment of two diseases for skin beauty, one is chloasma, and the other is post-inflammatory pigmentation after laser surgery. There are some melanin particles in melanocytes. The secretion of melanin particles will directly affect people's skin color. These two diseases are often accompanied by increased secretion of melanin particles and discharge disorders. The elimination of these two problems by drugs or other treatment means is not so immediate, so the clinical use of LED red light irradiation can accelerate the transport and metabolism of abnormally increased melanin particles. "Clinically, LED red light is rarely used to whiten normal skin, because its whitening effect on normal skin is limited." Li Jing explained that the energy density of LED red light is relatively low. Generally, it will not have a significant effect on normal skin within the specified energy density within the specified time. Using LED red light to improve chloasma and pigmentation can not turn white immediately after one irradiation. The normal course of treatment is irradiation once a week. After about 10 times of treatment, chloasma and pigmentation will be significantly improved. For many people, they personally prove that their skin will be obviously white with a color number through the "treatment" of the whitening cabin. Li Jing said that the secret of whitening lies in the "moisturizing cream" applied before entering the whitening cabin. It is understood that the merchant's whitening cabin generally allows consumers to apply a layer of so-called "moisturizing cream" on the whole body before entering the warehouse. Although the whitening products applied by various beauty agencies on the surface of consumers are different, they all have one thing in common, that is, the products contain a certain amount of whitening agent - titanium dioxide. Li Jing introduced that titanium dioxide is an inorganic substance, non-toxic, with the best opacity, the best whiteness and brightness. It is considered to be the whitest substance in the world today. One gram of titanium dioxide can whiten an area of 450 square centimeters. At the same time, titanium dioxide has good UV masking effect, so it is often used as sunscreen. Before entering the cabin, consumers are covered with cream containing titanium dioxide, because the cream is oily. After leaving the cabin, even after bathing, the cream will remain on the skin surface, and the skin will naturally "turn white". "This white belongs to the false white of pure physical reason, which has nothing to do with the red light irradiation of LED." Li Jing stressed. Only in peacetime can we become "Snow White" Not only the whitening cabin, but also products such as headlights and spectrometers appear on the Internet. Businesses also claim that they can irradiate whitening. "These products also use the principle of LED red light." Li Jing said that compared with the wishes of consumers, the whitening effect of these products may be quite limited. It is reported that in clinic, the more common whitening treatment items are mainly photon rejuvenation and laser rejuvenation whitening. "Both use the selective photothermal effect of laser and intense pulsed light to make the melanin of human skin absorb the heat inside the laser or photon, and then solidify or explode." Li Jing introduced that after photon rejuvenation, people will find that the freckles on their faces become darker, indicating that melanin is heated and solidified after absorbing photon energy, and then a small scab is formed on the skin surface. After 7-10 days of metabolism, it will apoptosis and fall off, and then the superficial color spots will fall off. Li Jing stressed that these two treatments require very professional laser and strong pulsed light to achieve the effect. They belong to medical behavior. They are treatment projects that require the use of formal medical equipment in medical institutions and operated by doctors. Beauty salons or skin management centers have no medical qualification, so it is unsafe to carry out these treatments. In addition to photoelectric whitening, Li Jing suggested that some skin care products with whitening effect should also be used at home to achieve the best effect. For example, skin care products containing tranexamic acid, glutathione, vitamin C, vitamin E, arbutin, fullerene, hydroquinone and other components have a certain whitening effect. They can act on different links of melanin production and metabolism to achieve whitening effect. "However, the addition of these substances will be strictly in accordance with a certain proportion, because the concentration is too high, it will stimulate the skin. Therefore, the content of these substances in cosmetics will not be too high, and it needs to accumulate skin care over time to achieve the whitening effect." Li Jing said. Finally, Li Jing stressed that no whitening method can achieve an immediate effect. If you want to have white skin, you also need to cooperate with good living habits, such as not staying up late, paying attention to moisturizing and sunscreen. You can become "Snow White" over time. (Xinhua News Agency)