Why use AHA(Alpha Hydroxy Acid) in cosmetics?

What is fruit acid?

AHA is a variety of organic acids extracted from fruits and is an active ingredient found in many natural fruits or yoghurts. Contains grape acid, malic acid, citric acid and lactic acid. Among them, glycolic acid extracted from sugar cane is the most widely used.

The cosmetic effect of AHA on the skin was discovered in the 1970s by Dr. Eugene J. VanScott of the United States and Dr. Ruey J. Yu of the Chinese American. Due to the excellent efficacy of AHA, it has become the most indispensable means for dermatologists in the field of adjuvant therapy and home care.

Classification of AHA

According to the molecular structure, the fruit acid can be divided into 37 kinds of glycolic acid, lactic acid, malic acid, tartaric acid, citric acid and mandelic acid. However, in the medical beauty industry, the most commonly used ingredients are glycolic acid and lactic acid.

  • Glycolic acid has the smallest molecular weight (76) in fruit acids and is therefore the easiest to penetrate the surface layer of the skin. The effect of absorption is also the most obvious, and it is the most commonly used fruit acid for skin rejuvenation.
  • Lactic acid has the second smallest molecular weight (90) in fruit acids. Because it is highly moisturizing and natural ingredients do not irritate human skin, it is widely used to improve dryness and keratosis.

PH value

In the fruit acid product, it is important to balance the acidity and alkalinity of the solution system, and the stable balance is more important than the concentration of fruit acid. According to the study, the effect of fruit acid is best when the pH is in the acidic range of 2.5-3. But the irritancy also increases. At present, the concentration of fruit acids in cosmetic products is less than 5%, and the PH value is above 3. Efficacy can only focus on exfoliation and moisturizing effect, no obvious effect on wrinkle whitening.

AHA concentration

Very low concentration of fruit acid, only moisturizing effect. Exfoliating is only possible when the concentration is slightly increased. It can break the connection between the cells of the stratum corneum and promote the metabolism of the skin.

  1. The effect of different concentrations of fruit acid
    low concentration of fruit acid (less than 10%): fruit acid can reduce the coagulation force between epidermal keratinocytes, can remove aging keratin, improve rough, dull, conditioning skin.
  2. Medium concentration of fruit acid (10% -30%): fruit acid effect can reach the dermal tissue, good effect on acne, dilute dark spots, smooth wrinkles

Mechanism of action of fruit acid

Degradation of desmosome by activation of steroid sulfatase and serine protease reduces the adhesion of the major constituent cells of the epidermis. Regulates the process of keratin formation, causing the aging cuticle to fall off. Avoid excessive accumulation of the stratum corneum to achieve more precise exfoliation.

It can remove dead cells that are ineffective at the opening of the sebaceous gland, making the excretion of sebaceous glands more patency. In order to prevent the pores from being blocked by sebum, the keratinization of the hair follicle catheter tends to be normal.

Promotes epidermal cell renewal time and rate increase, thereby promoting skin renewal.

Effect on the skin

  • By regulating keratinocytes, the keratinization process is normal, the stratum corneum is smooth and the epidermis is thickened.
  • The surface layer of the skin is normally aligned to achieve renewal and reconstitution of the epidermis. Thereby improving the appearance of the skin.
  • Improve excessive accumulation of keratinocytes and accelerate melanocyte detachment. Decreases the pigment, thus diminishing the color shift and brightening the complexion.

Usage notice

  • According to a study by the US Food and Drug Administration (FDA), if a product with a fatty acid content of 10% and a pH of 3.5 is continuously received. After four weeks, the skin’s UV resistance is reduced by 18%, which is more susceptible to sunburn than others. As a result, many people began to doubt the efficacy of fruit acids and their side effects. In fact, when using skin care products containing fruit acids or chemically rejuvenating skin acids, you can use your sunscreen work well.
  • In order to maximize the effectiveness of fruit acid products, choose a facial cleanser containing fruit acid. It can remove dead skin while washing the face, and can also be combined with fruit acid moisturizer to make the acid evenly stay on the skin. As for the sunscreen containing fruit acid, it is not necessary, as long as you choose SPF 15 or above sunscreen.
  • When using a fruit acid product, even if it is cloudy, apply sunscreen products because there will be more UV rays that reflect sunlight on cloudy days. If you need to use products that can resist UVA and UVB at the same time and have a sun protection index of 15 or above, sun protection work can be done.
  • If you are buying a fruit acid product, don’t worry too much. You may want to apply a small area of ​​the product first. After 5-10 minutes, see if the skin has an allergic reaction. If you find that your skin is red and painful, or you have an unbearable burning sensation, you should give up buying.

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