1. Generally we think that AHAs are alpha-hydroxy acids, which are organic acids extracted from fruits, including grape acid, malic acid, citrus acid and lactic acid. It can remove aging keratin accumulation in the stratum corneum of the skin, increase the thickness of the dermis, improve aging skin damaged by ultraviolet rays, and promote skin renewal and collagen synthesis.
Currently used in skin care products are generally third-generation products. First generation: also the most common AHA, such as glycolic acid (can be extracted from sugar cane) mandelic acid, lactic acid, tartaric acid, citric acid (citrate), etc.
The most common one is glycolic acid. Generally speaking, the overall concentration of glycolic acid (or combined with lactic acid) can reach 4-8%. Of course, there are higher concentrations in the United States, such as 12%, 15%, etc. At the same time, the best pH for onset of action is around 3-4. If it is too low, it will obviously irritate the skin, but if it is too high, it will not have the desired effect.
Applicable skin: non-sensitive skin with poor keratin metabolism, skin with closed acne, skin that wants to accelerate whitening, skin that is too dry, skin similar to ichthyosis or ichthyosis, and needs exfoliation Skin etc.
Main function: exfoliate old cuticles, avoid cuticle accumulation, and clear pores. Many medical aesthetics also use high concentrations of fruit acids for skin rejuvenation.
How to use: Start with a low concentration (1-4%). If the skin is seriously damaged, such as sunburn or allergies, the skin needs to be repaired. You can use a soothing and moisturizing mask for three days to adjust the skin to a healthier state. Within 3-7 days of first use, some people may experience peeling, serious oil production, etc. Don't worry, the skin will have a stronger water storage capacity after it adapts.
Be sure to pay more attention to sun protection when using fruit acids. When using fruit acid for skin care, you should not use other exfoliating products, do not rub the skin at will, and avoid using cosmetics with acidic ingredients such as A acid and salicylic acid.
Wash your face and use lotion for 20 minutes before using fruit acid products. Apply to the T-zone first and then extend to the face, from the thickest to the thinnest areas of the cuticle, with the eye area and lip area last. AHA products that are too concentrated can be neutralized with lotions. Use once a week as needed. It should not be used by patients with severely allergic skin and those undergoing dermatological treatment. Winter and after summer are the best times to use AHAs.
2. Salicylic acid, also known as BHA, is a fat-soluble organic acid. Not only can it treat multiple causes of acne at once, but it’s especially effective when combined with benzoyl peroxide. Dermatologists have been using salicylic acid as an exfoliant for decades.
Main functions: Effectively inhibit acne and acne, has bactericidal function, and can exfoliate and improve the symptoms of enlarged pores.
Side effects: Wiping salicylic acid toner products with cotton pads may cause peeling on the hands, so remember to wash your hands after applying salicylic acid products.
How to use: It is recommended to refer to fruit acids in the initial stage, and I will not repeat the description here.
Salicylic acid concentration selection: Generally, 0.5%-2% is enough for daily use. Continuous use of salicylic acid at too high a concentration (5%) for a long time has been proven by studies to significantly reduce skin thickness.
A fruit acid and salicylic acid can be said to be one of the magic weapons for skin rebirth. Products with these two ingredients can not only speed up the renewal of keratinocytes, improve the texture of the skin, and reduce the damage of ultraviolet rays to the skin. damage and delay the progression of skin cancer caused by sunlight.
In addition, fruit acid or salicylic acid products can also improve the structure of the skin, promote the production of collagen, and thereby strengthen the protective function of the skin. Exfoliating the face can also unblock the pores, allow the oil in the pores to metabolize normally, and avoid the occurrence of acne and acne. It can also enhance the penetration of bactericidal ingredients and effectively eliminate the bacteria that cause acne.
Extended information
The difference between fruit acid and salicylic acid:
1. Different solubility properties. The biggest difference is that AHA is water-soluble, while salicylic acid is fat-soluble. This makes it easier for salicylic acid to penetrate into oil-filled pores and remove aging keratinocytes in the pores.
2. Suitable for different skin types. Fruit acids are more suitable for use on skin that has been aged due to UV damage, and salicylic acid is most suitable for the treatment of blackheads and acne.
3. The functions are different.
Fruit acid acts on the surface of the skin, but it can accelerate melanin metabolism and add rich antioxidant ingredients. Its main function is to fade spots, acne marks, whiten and tighten the skin; salicylic acid can not only target old dead skin cells on the surface of the skin, but also It can penetrate deep into pores to cleanse, and its main function is to improve skin problems such as acne, blackheads, enlarged pores, acne, and whiteheads.
Reference materials: Baidu Encyclopedia - aha
Baidu Encyclopedia - Fruit Acid
People's Daily Online - What is Salicylic Acid and can it really help acne-prone skin? Is it effective