How to use glycolic acid?

The glycolic acid is an alpha-hydroxy acid (AHA) derived from natural sugars such as sugar cane, beetroot or grapes. Its small molecular size (76.05 g/mol) makes it one of the most effective exfoliating active ingredients in cosmetics. Used in numerous treatments – serums, creams, masks or peels – the glycolic acid acts on the stratum corneum by weakening the lipid bonds that hold dead cells together. This process accelerates the skin’s natural desquamation, unclogs pores and improves skin texture. The complexion is then more even and luminous, pores are less dilated, and imperfections and scars are diminished.

Beyond its exfoliating action, the glycolic acid contributes to regulating sebum production, making it favourable for combination and oily skin. It also helps to reduce pigmentation spots by inhibiting melanogenesis and stimulates the synthesis of collagen and elastin, thereby enhancing the skin’s suppleness and elasticity. Thanks to these various properties, glycolic acid can be suitable for different skin types, whether they are dull, mature, prone to melasma or acne-prone. However, sensitive or reactive skin should remain cautious, as the glycolic acid can be quite irritating.

Note : The concentration of the chosen treatment should be tailored to the skin type. In cosmetics, formulations typically range between 4 and 10% glycolic acid to be effective. Sensitive or inexperienced skin should favour lower concentrations (≈ 5%), while more resistant or accustomed skin can tolerate slightly higher levels.

As an exfoliant, glycolic acid poses a risk of drying out the skin. To counteract this effect, apply a moisturising cream suited to your skin type after using a glycolic acid treatment. Exfoliation also renders the skin more vulnerable to external aggressors, notably UV radiation. For this reason, glycolic acid is best used in the evening, when cellular regeneration reaches its peak. In the morning, it is essential to apply a broad-spectrum sunscreen (SPF 30 minimum), regardless of weather conditions. Without protection, the skin will redden more rapidly and the risk of sunburn will be greater.

It is also advisable to start with a low concentration (≈ 5%) and gradually increase it according to your skin’s tolerance. It is preferable to introduce glycolic acid gently to avoid redness or irritation. Likewise, avoid combining several irritant actives on the same day, such as other AHAs or retinoids, in order to minimise the risk of sensitivity.

In terms of formulation, anything is possible: you can opt for a lightweight leave-on serum if you seek rapid penetration and a gradual effect. Glycolic acid creams, meanwhile, are particularly suitable for more sensitive skin, as the presence of emollients helps mitigate the active ingredient’s potential irritancy. As a general rule, it is also advisable to favour formulations that combine glycolic acid with soothing or hydrating ingredients, such as hyaluronic acid or bisabolol, to enjoy exfoliation while minimising side effects. Finally, masks or peels with a higher concentration should be reserved for occasional use, at most once or twice a week.

How to use Typology products containing glycolic acid?

At Typology, we have formulated three products containing glycolic acid:

• The exfoliating serum : This daily-use serum combats blackheads and dilated pores, for a smooth, even complexion. Formulated with 10% glycolic acid, it also contains soothing, anti-inflammatory and restorative ingredients such as bisabolol and chamomile extract. After make-up removal and thorough cleansing, apply three to four drops of serum to your face, then gently massage for a few moments to allow the active ingredients to penetrate. This treatment does not require rinsing, however this is not always the case with glycolic acid products, hence the importance of always carefully reading the manufacturers' instructions.

• The peeling mask : This treatment combines the action of four AHAs and a PHA to work at various depths of the epidermis, removing dead skin cells. This mask-gel is applied once or twice a week for ten minutes before being rinsed off.

• The exfoliating night cream : Designed for daily use, it works day after day to unclog pores, limit their dilation and prevent the appearance of blackheads.

Certain clinics and dermatologists offer glycolic acid peel sessions to reduce wrinkles, imperfections and pigmented spots, and to restore radiance to the skin.

Before any glycolic acid peel session, a prior medical consultation is essential. The practitioner examines the skin, assesses the patient’s needs and determines whether the peel is appropriate. It is also at this stage that they select the glycolic acid concentration (typically between 20% and 70% in a clinic, versus 4% to 10% in cosmetic products) and decide on the application time. The doctor outlines the protocol, answers questions and provides a detailed quote. A preparatory skin-conditioning phase is often recommended, involving daily application of a cream containing a low concentration of glycolic acid for about two weeks to optimise exfoliation.

The chemical peel session itself is relatively simple and quick : after a thorough facial cleanse, the practitioner applies the glycolic acid solution using a brush or compress. The exposure time is brief—on average between 2 and 5 minutes—but it may be accompanied by a tingling or warming sensation. A neutralising solution is then applied to halt the acid’s action, before rinsing and soothing the skin with a moisturising cream. Each session lasts around 20 minutes, with no social downtime required, but strict sun protection (minimum SPF 30) is essential in the days that follow.

Most professionals recommend three to six glycolic acid peel sessions, spaced two to three weeks apart.

Contraindications : As with any aesthetic dermatology procedure, the peel with glycolic acid is not suitable for everyone. It is not recommended during pregnancy, breastfeeding, a known allergy, an active skin lesion or infection. The use of photosensitising medications is also a contraindication.

• WON Y. H. & al. The effet of glycolic acid on cultured human skin fibroblasts : Cell proliferative effect and increased collagen synthesis. The Journal of Dermatology (1998).

• MAIBACH H.I. & al. Increased in vivo collagen synthesis and in vitro cell proliferative effect of glycolic acid. Dermatologic Surgery (1998).

• GARG G. & al. Chemical peeling - glycolic acid in varying concentrations and time intervals. Indian Journal of Dermatology, Venereology and Leprology (2001).

• MURUGAIAH C. & al. Efficacy and safety of superficial chemical peeling in treatment of active acne vulgaris. Anais Brasileiros de Dermatologia (2017).