Signs of skin ageing: what are the effects of mandelic acid?

Would promote the production of new collagen and elastin.

Stimulates the secretion of sebum.

Reduces the appearance of wrinkles.

Would improve the skin's elasticity.

Inevitably, ageing affects the entire body and the skin is the most exposed to the effects of time. Overall, skin ageing is characterised by a degradation of all the skin's components. Themature epidermis then exhibits numerous characteristics, which can intensify with age and due to environmental factors.

• Loss of radiance: Mature skin gives the impression of a blurred complexion, which is due to an accumulation of old cells on the skin's surface. As it ages, cellular renewal becomes slower. Moreover, with age, the epidermis receives fewer nutrients and oxygen, due to a slowdown in blood flow.

• Loss of elasticity, skin sagging: With age, the skin loses its ability to return to its original shape when pinched or stretched, becoming "slack" with visible sagging. This property is made possible thanks to elastin, a protein present in the dermis, which contributes to the skin's suppleness. However, over time, the amount of elastin gradually decreases to such an extent that mature skin contains five times less elastin than "young" skin.

• Loss of volume: Cheekbones, eye contours... certain areas of the face are prone to a loss of density, resulting in sagging skin. This loss of bounce is caused by dermal water loss with a decrease in the natural content of hyaluronic acid, muscle atrophy, the melting of subcutaneous adipose tissue, and loss of bone density. It is exacerbated by a deterioration in the structure of the dermis, which is primarily composed of collagen and elastin.

• Wrinkles: primarily around the eye contour and corners of the mouth, grooves form and settle on the face. Among these wrinkles, some are static, others are dynamic. Various mechanisms underlie their appearance: weakening and oxidation of collagen structures, excessive contraction of facial muscles, repeated exposure to the sun, etc.

• Age Spots : more visible and numerous, this common form of hyperpigmentation most often occurs in people over the age of 40. They are caused by frequent oxidation of skin cells which exacerbates skin ageing. Excessive and repeated exposure to oxidants such as the sun can induce an excess of melanin.

To enhance the quality of the skin, making it denser and more elastic, several solutions exist, including chemical peels. Their purpose? They help to delay the effects of skin ageing, due to their ability to promote cell proliferation and metabolic activity, thereby boosting the production of collagen and elastin fibres, thanks to the exfoliating action they induce. As a bonus, wrinkles are "smoothed out", sun spots are faded, and the complexion is brightened.

Themandelic acid does everything that other alpha-hydroxy acids (AHA) do, and even more. What sets it apart from other fruit acids? It's its antibacterial, anti-inflammatory, antioxidant and gentle action. Indeed, most publications report its benefits in the treatment of acne and hyperpigmentation, without the risk of redness or irritation. In its natural state, mandelic acid is derived from the bitter almond, a non-edible fruit of the wild almond tree.

Mandelic acid has a larger molecular structure than other popular AHAs: nearly twice as large as that of glycolic acid. This greater size means it is absorbed by the skin more slowly and does not penetrate as deeply into the epidermis when applied. This therefore makes it gentler, and individuals with sensitive or acne-prone skin have fewer issues with mandelic acid than with other AHAs.

It is proven that mandelic acid exfoliates the skin. The observed effects depend on the concentration of mandelic acid in the skincare product. It is generally used in skincare at a concentration of 10% or less. However, doctors can prescribe or apply, as part of a chemically controlled dermatological peel for example, products with a higher concentration of active ingredients (> 10%), yielding more "spectacular" effects.

In a study, CULBERTSON E. & al. assessed the effects of a mandelic acid skincare treatment on the improvement of mature skin quality, characterised by its extensibility property. This single-centre clinical study of four weeks was conducted on 24 patients aged between 42 and 68 years, presenting with skin laxity and fine lines around the eyelids. They were instructed to apply a mandelic acid-based treatment on one side of the face twice a day, specifically a serum with 6% mandelic acid during the day and a 4% mandelic acid night cream in the evening. The viscoelastic properties of the skin of the lower eyelids were evaluated using a Cutometer, a tool designed to assess the effectiveness of a treatment by measuring the biomechanical properties (viscoelasticity) of the upper layers of the epidermis.

Researchers have found that the viscoelasticity of the skin under the eyes can be significantly improved by using mandelic acid twice a day for a period of 4 weeks. Similarly, an increase in skin firmness has also been observed. Subjectively, an improvement in the appearance of fine lines at the outer corner of the eyes has also been demonstrated after four weeks of topical application. Although it was not directly tested with the Cutometer, it appears that improvements on other treated areas of the face and neck have been noted. The result? Firmer, more elastic skin with fewer wrinkles in the orbital area. The researchers suggest that this phenomenon is explained by the ability of mandelic acid to stimulate dermal fibroblasts to produce more collagen, elastin and glycosaminoglycans in the papillary dermis through an indirect and as yet unknown mechanism.

From which perspective should this article be considered?

Although improvements have been observed in skin elasticity, firmness does not show any significant difference. The small number of volunteers is also a factor to consider. Furthermore, it would be worth considering testing on other areas of the face prone to skin sagging. Finally, it would also be necessary to evaluate how long the effect is maintained over time.

Mandelic acid also reportedly helps to diminish the appearance of wrinkles and fine lines. By accelerating the natural exfoliation of damaged outer layers of the epidermis, it also speeds up skin regeneration. This thinning of the stratum corneum certainly improves the texture and radiance of the skin, but also progressively, continuously and repeatedly reduces the appearance of fine lines. In addition to this, mandelic acid has been shown in a study to stimulate the production of elastin and collagen. It also stimulates or balances sebum production, which helps to maintain skin hydration when it is dry or damaged. This improvement in wrinkles and fine lines can be observed in patients with Fitzpatrick skin types I to VI, without the risk of post-inflammatory hyperpigmentation, erythema and the formation of any other adverse effects on the epidermis that accompany skin treatments with glycolic acid.

• TAYLOR M. B. Summary of mandelic acid for the improvement of skin conditions. Cosmetic Dermatology (1999).

• ROTSZTEJN H. & al. The impact of azelaic and mandelic acid peels on sebum production in ageing women. Progress in Dermatology and Allergology (2013).

• CULBERTSON E. J. & al. Effects of topical mandelic acid treatment on facial skin viscoelasticity. Rapid Communication (2018).