Skin Application: What Are the Benefits of Mandelic Acid?

Mandelic acid (INCI name: Mandelic Acid), also known as amygdalic acid, is a type of alpha-hydroxy acid (AHA) along with glycolic acid, lactic acid, citric acid, malic acid and tartaric acid. Naturally or synthetically derived, this organic acid comes from the bitter almond, although it can be found in many other plants.

In particular, it helps to provide a more targeted exfoliation. In fact, it exerts a non-mechanical, less abrasive keratolytic action that removes dead cells clogging pores. Its large molecular size (MW = 152.14 g/mol) allows it to stay on the surface of the skin and exfoliate on the surface: each type of AHA has its advantages layer by layer due to their molecular size. It thus improves the condition of the skin without causing any side effects.

Escherichia coli, Staphylococcus aureus and Candida albicans are normal flora in the human body. However, increased numbers of these bacteria can cause infections in some cases such as acne. The antibacterial nature of mandelic acid makes it very effective in reducing existing acne and preventing future breakouts.

Its advantage over other agents is also its anti-inflammatory effect, causing less erythema and hyperpigmentation as other AHAs can. Add to that its ability to slowly and gently penetrate the skin, and the way it effectively exfoliates the skin's surface without over-drying it, and you have the perfect acid for acne-prone skin.

The stratum corneum, the upper layer of the epidermis, is made up of 10 to 20 layers of dead cells (corneocytes). These are continuously removed and replaced by new cells from the lower layers: this is the process of desquamation. A complete cycle of cell renewal lasts on average 28 days.

However, this natural process of elimination slows down with age and can take up to 45 days to complete in older people. The accumulation of dead cells on the surface of the skin results in a dull, gray appearance. Skin that is less smooth on the surface reflects light more slowly.

The use of mandelic acid is the perfect treatment for dull and tired skin. It will help remove excess dead skin cells to make room for new skin cells for a brighter and more even skin. Also, the accumulation of corneocytes can clog pores; its elimination thus makes it possible to fight against the formation of imperfections (dilated pores, blackheads, pimples).

Because mandelic acid does not trigger an inflammatory response in the skin, unlike other acids such as glycolic acid, it is particularly effective in reducing the pigmentation of brown spots. From age spots to post-acne hyperpigmentation and melasma, mandelic acid can actually fade the appearance of pigmentation spots of all types. By thinning the stratum corneum, the melanin pigment content of the basal layer is reduced and dispersed more evenly, improving hyperpigmentation and evening out skin tone.

More precisely, mandelic acid with its exfoliating properties will remove dead cells enriched in melanin from the skin surface. Each layer dissolved in this way helps to reduce the appearance of pigmented marks until they "completely" disappear. In addition, due to its high molecular weight, mandelic acid tends to stay on the surface of the skin longer, penetrates slowly into the superficial layers of the epidermis and thus produces a uniform epidermal effect. Research conducted in 1999 even showed that mandelic acid can improve melasma hyperpigmentation by 50% in about 4 weeks with a 10% mandelic acid lotion.

Mandelic acid can also be used on mature skin. In fact, it can help reduce the effects of the aging process, particularly in reducing the appearance of wrinkles and regaining the elasticity of the epidermis. During the exfoliation process, mandelic acid helps to remove damaged and aged epidermal cells in a controlled manner and replace them with younger, firmer cells by activating skin turnover, thereby reducing the appearance of wrinkles.

Further research indicates that chemical exfoliants such as mandelic acid stimulate dermal fibroblasts to promote the synthesis of new collagen, elastin and glycosaminoglycans (hyaluronic acid), skin building blocks, in the papillary dermis by an indirect, yet unknown mechanism.

Another study showed that mandelic acid stimulates or balances the production of sebum and thus helps to maintain the hydration of the skin when it is dry or damaged. Finally, a study conducted to evaluate the effectiveness of a mandelic topical treatment revealed that after four weeks of use, it firmed the skin by 23% and increased the elasticity of the skin of the lower eyelids by 25%. The authors of the study thus concluded that mandelic acid is an effective option for improving skin quality.

One of the benefits of mandelic acid is its ability to reduce pore size. But how does it do this? Studies explain this result by mandelic acid's property of inhibiting comedo formation, resulting in fewer follicular openings. Since mandelic acid exfoliates and unclogs pores, a "side" effect of this action is a reduction in pore size.

Mandelic acid also has antioxidant potential. Indeed, studies have shown that it can be used to minimize oxidative stress caused by reactive oxygen species, by donating an electron to the free radical and thus reducing their level in the cells. Therefore, mandelic acid could be an interesting bio-active agent to prevent and inhibit damage to cells and biologically important substances such as DNA and proteins by free radicals, which can lead to a number of complications such as premature aging of the skin.