Acid, salicylic acid, mandelic acid, lactobionic acid

A Dermatology Professor's Detailed Analysis: Finding the right acid for yourself

By Ying-Chun, Wu

I often hear people talking about retinols, salicylic acid, mandelic acid, and lactobionic acid. What are these acids exactly? Everyone dreams of perfect, clear skin but people often don’t see the results they want due to the irregular accumulation of keratinocytes on the skin’s surface. This uneven keratin layer cannot reflect light, making the skin look dull. Moreover, aged keratin further increases absorption of skincare ingredients, preventing nutrients from penetrating the skin and reducing the metabolic function of the cells, leading to dryness. Acid-based exfoliants with skin-renewing functions have become more and more popular over the years. After more than 30 years of development, there are innumerable options available. So, what are the functions of these now-popular acids, such as mandelic acid, retinoic acid, salicylic acid, and lactobionic acid? After reading this article, you’ll be able to choose the right acid for your skin’s needs.

Mandelic acid is gentle and effective, making It the first choice for at-home skin care

Mandelic Acid is a natural organic acid derived from almonds, which has been widely used in skincare products in recent years. Chemical peels began to gain popularity in the 1908ss, both in medical aesthetics or at-home exfoliation. Whether a medical or at-home skin peel, glycolic acid was the main ingredient. However, because glycolic acid is water-soluble and has small molecules, it penetrates faster and deeper, which can lead to irritation. In 2006, the Yingjue Medical Aesthetic Clinic pioneered the use of mandelic acid for chemical peel treatments. Mandelic acid is fat-soluble and can therefore stay in the shallow layer of skin to combine with keratin.Its molecules are larger and cannot penetrate into the deeper layers of the skin like glycolic acid, resulting in reduced irritation and avoiding skin burning or excessive dryness. Moreover, it effectively enhances skin renewal and brightening skin tone through promoting keratinocyte metabolism. Recognizing its potential for at-home use, research began into mandelic acid's suitability for home exfoliation. In 2011, after repeated clinical experiments, DR.WU launched the Mandelic Acid Brightening Essence 18% for home use, which gradually became the mainstream ingredient for home skin peeling.

The chemical structure of mandelic acid is similar to antibiotics, originally treating urinary tract infections before it was found to be effective against acne bacteria. In addition, mandelic acid regulates keratin turnover, which removes the accumulation of dead skin cells that make the skin appear dull, resulting in smoother, brighter skin. Another characteristic of mandelic acid is its similar structure to tyrosine, which has the ability to act as a tyrosinase inhibitor. It can inhibit the activity of tyrosinase and prevent tyrosine from being oxidized into melanin, while improving uneven skintone and melanin deposition.

Vitamin A acid, the first choice for aging skin with anti-aging and wrinkle soothing properties

Retinol, retinol aldehyde, and retinol ester are all different active forms of vitamin A. The skin can use retinol acid, but because it is more irritating and has greater side effects, only other forms of vitamin A can be added to skin care products. After being absorbed into the skin, it is converted into retinol acid for use.

Retinol acid is a comprehensive skin care ingredient, and its main effects can be divided into four categories:

1.Anti-aging and wrinkle reduction: It stimulates skin growth and differentiation, promotes collagen synthesis, improves skin structure and texture, and is also suitable for improving aging-related enlarged pores. As early as 1995, the first generation of retinoic acid was approved by the US FDA to slow down fine lines and photoaging.

2.Treating Acne: Retinoic acid can reduce e sebum secretion, prevent pore blockage, and reduce the occurrence and development of acne. Oral or topical A acid is an important means for dermatologists to treat acne.

3.Reducing pigmentation: Retinoic acid can inhibit the production of melanin, reduce pigmentation, and lighten existing dark spots.

4.Improving skin texture: Retinoic acid can promote the renewal of keratin cells, remove dead skin cells, and improve the skin texture to make the skin become smoother.

Salicylic acid dissolves sebum in pores, making it effective in treating blackheads

Salicylic acid, also known as BHA (beta hydroxy acid) is a large molecule with lipophilic properties that exists in willow bark. It is a larger molecule and was initially used as a medicinal agent for softening calluses or dissolving keratin. It wasn’t until, in 1997, a dermatologist in the United States published in the American Journal of Dermatology and Surgery, that 30% salicylic acid can be used as a skin peel. Similar to fruit acid peels, it can help fade pigmentation, reduce pore size, diminish fine lines, and improve the look of sun-damaged skin. Thus, salicylic acid has become a popular ingredient in skincare products. Most products contain up to 2% of salicylic acid.

Salicylic acid penetrates slightly deeper into the skin compared to mandelic acid and has a slightly higher likelihood to irritate the skin. Its most well-known benefit is its ability to penetrate deep into the pores to dissolve blackheads and pimples. Due to its fat-soluble properties, it can fuse with lipids to penetrate deeper down into the pores, dissolving accumulated dead skin cells and sebum. It’s particularly effective against blackheads without the irritation caused by glycolic acid.

Lactobionic acid Highly effective moisturizing First choice for dry and sensitive skin

Lactobionic acid, also known as the third generation of alpha hydroxy acids (AHAs), shares similar benefits with other members of the acid family. It accelerates the renewal of the skin cells and promotes skin metabolism while causing minimal irritation to the skin and is as mild as physiological saline solution.

One of the most notable skincare benefits of lactobionic acid is its moisturizing effect. Because there are 8 hydroxyl groups, it can capture more water molecules from inside and outside of the skin– each unit of lactobionic acid can absorb approximately 70 grams of water, surpassing common moisturizing ingredients like glycerin and sorbitol. Lactobionic acid can also form a protective film over the skin to lick in moisture, maintaining excellent water retention. Moreover, it has strong antioxidant properties, which can prevent oxidation which damages cell membranes. This is similar to the effects of L-ascorbic acid (vitamin C) and gluconolactone. Lactobionic acid also assists in collagen synthesis, promoting youthful and plump skin, making it well-suited for anti-aging skincare applications.