Differences between glycolic acid, lactic acid and salicylic acid
Fuglycolic acid, lactic acid and salicylic acid are all genus of skin care acids, but their properties, efficacy, and application to skin types are different. Details are as follows.

1. Chemical structure and characteristics
Glycolic acid is an α-hydroxy acid with a simple and small molecular structure. It is highly hydrophilic, can be quickly dissolved in water, and is mostly in solution form in skin care products. Lactic acid is also an α-hydroxy acid, but its molecules are slightly larger than glycolic acid. Lactic acid has a unique mild and sour taste, high solubility in water, and moisturizing properties. Salicylic acid is a β-hydroxy acid with a benzene ring structure, which is different from the former two. It has good fat solubility and can dissolve into skin oil, which makes it deep into the hair follicle sebaceous glands.

Second, the difference in efficacy
Glycolic acid is mainly responsible for keratin metabolism, which can loosen the connection between keratinocytes, promote the renewal of the stratum corneum, make the skin smooth and delicate, and has a good effect on improving dull skin tone and fading fine lines. In addition to the exfoliation function, lactic acid has strong moisturizing power. It can combine water molecules, leave water on the skin, make the skin hydrated, and is suitable for dry skin. Salicylic acid is good at relieving oil blockage, can penetrate deep into pores, clear oil, and resist Propionibacterium acne. It has significant effect on oily skin problems such as acne and acne. It has anti-inflammatory properties and can slow down skin redness, swelling and inflammation

III. Applicable to different skin types
Glycolic acid has high activity and strong exfoliation power, and is suitable for oily and well-tolerated skin. Beginners may have short-term tingling and redness, so sensitive skin should be used with caution. Lactic acid is mild and moisturizes well. It can be tried for dry and sensitive skin. However, high concentration of lactic acid may still cause irritation, and a skin test is required before use. Salicylic acid is especially suitable for oily and acne skin because it is fat-soluble. However, it is irritating to the skin. Use with caution for sensitive skin, and high concentration of salicylic acid needs to be used under professional guidance.

4. Precautions for use
All three are irritating to a certain extent. Before use, a skin test is required. Start with low concentration and less frequency, and increase after the skin adapts. Avoid the eye area and mucous membranes when using. Pay attention to sun protection after using glycolic acid and lactic acid. The skin is sensitive to ultraviolet rays due to exfoliation. Salicylic acid may be dry and desquamated during use, so it is necessary to strengthen moisturization. If the skin is uncomfortable or allergic after use, it should be stopped immediately, and if it is severe, seek medical attention.

To sum up, glycolic acid, lactic acid and salicylic acid have their own characteristics. When taking care of the skin, choose them carefully according to your own skin type and needs, so as to achieve the best skin care effect and protect the health and beauty of the skin.