Does salicylic acid have side effects?

1, salicylic acid: can remove the accumulation of aged keratin and improve skin quality; It can penetrate deep into hair follicles and effectively dry the purulent parts of facial blisters. There are many anti-acne products containing salicylic acid. Compared with fruit acid, salicylic acid is less irritating to the skin. 2, do not use sensitive skin, because it will be allergic to skin with acne whitening effect. 3. Salicylic acid, also known as BHA, B skin softening acid. Salicylic acid is a white crystalline powder, which exists in willow bark, white pearl leaves and sweet birch in nature. Salicylic acid is taken from Latin Salix, the Latin scientific name of willow. Salicylic acid has excellent ability to exfoliate and clean pores, high safety, and its stimulating effect on skin is lower than that of fruit acid, so it has become the new favorite of skin care products. Salicylic acid can lighten spots, shrink pores, remove fine lines and improve aging caused by sun exposure. Salicylic acid in the history of skin beauty has often heard advertising buzzwords recently, such as "old cutin removal, invisible pores" and "I just have a way to get it back for nothing", which makes people who love beauty flock to it. The protagonist who claims to have these magical effects is salicylic acid. Although people have become familiar with salicylic acid recently thanks to the media, salicylic acid is actually a very old skin medicine. Early salicylic acid is a drug used to soften hard skin or dissolve keratin, which has nothing to do with beauty. From 65438 to 0997, Dr. Kligman was published in the American Journal of Dermatology and Surgery. Using 30% salicylic acid as a chemical skin changing agent can achieve the same effect as 70% fruit acid skin changing agent, such as fading spots, shrinking pores, removing fine lines and improving aging caused by sun exposure. Since then, salicylic acid has become famous and salted fish has turned over. Different from the chemical structure of fruit acid AHA, β hydroxy acid of salicylic acid (BHA for short) has caused quite a stir in the medical field of beauty and anti-aging with a brand-new name-B skin soft acid. Albert M. Cligman salicylic acid, also known as o-hydroxybenzoic acid, has a molecular formula of C6H4(OH)(COOH) and a molecular weight of 138.05. It is white crystal, needle-like or powdery. Specific gravity 1.443, melting point 156℃~ 159℃. Soluble in ethanol, ether, acetone and turpentine. There are many derivatives of salicylic acid, one of which is aspirin, an old medicine commonly used in medicine. The principle of action of salicylic acid salicylic acid can dissolve the cement between the cuticles and make the cuticles fall off, so it can remove the accumulated thick cuticles and promote metabolism. Metabolism of the skin: The main function of the stratum corneum is to protect the cells in all layers of the skin. The metabolism of epidermal cells layer by layer will naturally move outward. After the outermost keratinocytes gradually age and harden, they will naturally fall off under normal circumstances. Old horniness without normal shedding will make the skin look rough and dull, slow down the metabolism of the skin, and even form acne to block pores. Exfoliating effect: salicylic acid can remove excess cuticle and promote the rapid renewal of epidermal cells; If the epidermal cells are fresh and full of vitality, it will naturally make the skin smooth and delicate. Shrink pores: Salicylic acid is fat-soluble, and can penetrate into the depths of pores along sebaceous glands that secrete oil, which is beneficial to dissolve the old accumulated cuticle in pores and improve the blockage of pores, thus blocking the formation of acne and shrinking enlarged pores. Prevention of acne: salicylic acid acts on hair follicle wall cells, which can help clear blocked hair follicles and correct abnormal cell shedding. It can prevent small acne from blocking pores and is most effective for blackheads. It can reduce the abnormal shedding of hair follicle wall and prevent new lesions, but it has no effect on reducing sebum secretion and eliminating acne bacilli. The role of salicylic acid is to clean the aged cutin, making the skin look more delicate and less prone to acne. Salicylic acid can exfoliate, promote skin metabolism, shrink pores, remove blackheads and acne, effectively dilute fine lines and wrinkles, and thus reproduce skin luster. Salicylic acid has excellent characteristics-fat-soluble, low irritation, and can penetrate deep into pores (1). The best choice for exfoliating sensitive and seborrheic skin: fruit acid AHA is water-soluble and has a small molecular weight, which can easily penetrate into deeper epidermis and even dermis. Fruit acid can directly affect the metabolism of epidermal basal cells, and also promote collagen proliferation in dermis. The higher the concentration, the faster the effect may appear, but the greater the relative damage may be. The fat solubility and molecular weight of salicylic acid BHA are also large, which can lock the action in the shallow stratum corneum without affecting the active epidermal cells. BHA is superior in stability and irritation, which makes users produce less irritation, such as tingling and burning. The chances of cumulative irritation and the degree of inflammation are also less than those of fruit acid. ((2). Sharp tool for removing acne and reducing pores: Salicylic acid has many superior characteristics, and the ability to remove blackheads is one of them. Because human cornea is rich in lipids, the fat-soluble characteristics of salicylic acid can penetrate into the stratum corneum and deep pores by fusing with lipids, but it will not cause irritation to dermal tissue. Compared with fruit acid itself, it is difficult to stay in pores for a long time, which limits the thorough cleaning of sebum accumulated in pores. If you want to treat acne in pores without burning the skin, you need to use the concentration and time of fruit acid very carefully and accurately. Fruit acid can dredge pores, just like opening a bottle cap, while salicylic acid can further remove waste from the bottle. BHA cleans up excessive sebum and keratin accumulated in pores, which helps to reduce the possibility of acne caused by hair follicle blockage and inflammation. After using salicylic acid for 2 months before treatment, the oil solubility of salicylic acid can penetrate into pores with strong sebum secretion and fat stratum corneum, fully remove the hyperkeratosis of stratum corneum and remove blackheads in pores. 1-2 months, the effect can only be exerted. Salises moisturizing gel, a salicylic acid product in medical and health products, contains 1.5%BHA (moderate, dry, sensitive and seborrheic skin), 1.5% salicylic acid, 4% lactic acid, 3% fruit acid and 0.2% vitamin B6. Use of seborrheic skin ● Its excellent acne removing effect comes from the addition of salicylic acid and lactic acid, which can not only effectively exfoliate, but also resist aging, make skin firm, smooth fine lines and fight wrinkles and melanin. ● Improve the skin with acne problems. Prevent and improve folliculitis and rosacea. Moisturize and prevent premature skin aging. ● As an auxiliary treatment and maintenance of acne-related skin, it is an oil-free gel with refreshing texture and easy absorption. The skin softening acid containing B has the functions of dissolving keratin, eliminating acne, renewing, regulating sebum secretion and resisting microorganisms. Lifebao water-daily renewal essence: 1.5%BHA (oily and acne skin), EFFACLARK0.3%LHA, 1.5% salicylic acid, malate ester and zinc PCA 0. 1% Suitable for oily skin, blackhead and acne skin. ● The efficacy is the same as that of vitamin A, but it is more tolerant. It can tighten pores and make skin glow again. PH5.5 is similar to that of skin, which can effectively resist bacteria and diminish inflammation. Using salicylic acid concentration limit to add low concentration salicylic acid to cosmetic care products has the function of exfoliating and treating acne, acne and even wrinkles; As for high concentration of medicinal salicylic acid, it can be used to treat warts, corns and other diseases. Because high concentration of medicinal salicylic acid has very strong keratin corrosion characteristics, it should be used with great care to avoid irritation to eyes or oral mucosa. [Salicylic acid concentration] Salicylic acid is widely used. It can be used for eczema, psoriasis, acne and dandruff removal. Salicylic acid with a concentration of 3-6% can exfoliate, and more than 6% is destructive to tissues. The concentration below 40% is suitable for treating corns, thick cocoons and viral warts. Salicylic acid can also be added to medicines for treating acne and dandruff. Now many well-known cosmetics have added salicylic acid. 1993, Clinique first introduced a moisturizing and refreshing hydrating cream containing 1% salicylic acid, which immediately became one of Clinique's most successful products. 1998 SK-II crystal skin-changing cream, in which 1.5%BHA is added to the original prescription of Pitera, and salicylic acid is used to compare the effect of peeling eggs on treating pores and keratin, which has triggered a market boom. Olay's popular product Revitalizing Essence Cream also contains 1.5%BHA. Because high concentration of salicylic acid is harmful to a certain extent, since 1999, the pharmaceutical department of the Ministry of Health has limited the concentration of salicylic acid in cosmetics to 0.2- 1.5%. Cosmetics containing salicylic acid must be warned to ensure the safety of long-term use, and children under 3 years old are not allowed to use them. ● Local effects: Excessive removal of stratum corneum will worsen the skin's defense, resulting in erythema, itching, tingling or allergies. Therefore, it is necessary to strengthen moisturizing repair when using salicylic acid, and it is best to avoid contact with eyes, face, reproductive organs and mucous membranes. There are also a few people who are allergic to salicylic acid, so any concentration of salicylic acid is not suitable for use. ● Systemic symptoms: For general skin care and a small number of users, there should be no systemic side effects. However, for patients who use salicylic acid on a large scale (more than 30% of the whole body area) or for a long time, special attention should be paid to the toxic effect of salicylic acid. Include tinnitus, dizziness, fatigue, nausea and electrolyte imbalance. These symptoms are more likely to occur in children and patients with renal and liver dysfunction. If salicylic acid is toxic, stop taking the medicine immediately. Precautions for the use of salicylic acid: 1. There are many kinds of exfoliating skin care products on the market, such as acid, alcohol (aldehyde), fruit acid, salicylic acid and even rhododendron acid, all of which have exfoliating and promoting skin metabolism. These exfoliating products cannot be used at the same time. 2. When the skin is fragile or allergic, such as sunburn, itching, tingling, peeling, etc. , not suitable for the use of salicylic acid products, it will cause excessive irritation or burns. 3. Exfoliation will reduce the protective effect of epidermal cells, so pay more attention to the use of moisturizing and sunscreen. 4. Sensitive and seborrheic skin needs exfoliation. It is best to choose salicylic acid or lactone-type gluconic acid with less irritation, which will not cause the burden on the skin.