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 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 shedding, unclogs pores and improves skin texture. The complexion then appears more even and luminous, pores are less enlarged, and imperfections and scars are diminished.

Beyond its exfoliating action, the glycolic acid contributes to regulating sebum production, making it appealing for combination and oily skin types. It also helps fade pigment spots by inhibiting melanogenesis and stimulates collagen and elastin synthesis, thereby enhancing skin 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 exercise caution, as the glycolic acid can be quite irritating.

Note : The concentration of the chosen treatment must be adapted to the skin type. In cosmetics, formulations generally range between 4 and 10% glycolic acid to be effective. Sensitive or novice skin should favor relatively low concentrations (≈ 5%), while more resistant or accustomed skin can tolerate slightly higher dosages.

As an exfoliant, glycolic acid poses a risk of drying out the skin. To counteract this effect, apply a moisturizing cream suited to your skin type after using a glycolic acid treatment. Exfoliation also increases the skin’s vulnerability to external stressors, particularly UV radiation. For this reason, glycolic acid is best used preferably in the evening, when cellular regeneration peaks. In the morning, it is essential to apply a sunscreen with a broad-spectrum SPF of at least 30, regardless of weather conditions. Without it, the skin will redden more quickly and the risk of sunburn will be higher.

It is also advisable to start with a low concentration (≈ 5%) and gradually increase it based on your skin’s tolerance. It is best to introduce glycolic acid slowly to prevent redness or irritation. Similarly, avoid combining multiple irritating actives on the same day, such as other AHAs or retinoids, to reduce the risk of sensitivity.

When it comes to formulation, anything is possible: you can choose a light, leave-on serum if you’re seeking rapid penetration and a progressive effect. Creams containing glycolic acid, on the other hand, are particularly suitable for more sensitive skin, since the inclusion of emollient agents helps reduce the active ingredient’s potential irritancy. In general, it’s also advisable to favor formulas that combine glycolic acid with soothing or hydrating actives, such as hyaluronic acid or bisabolol, to benefit from exfoliation while minimizing side effects. Finally, higher-concentration masks or peels should be reserved for occasional use, no more than once or twice a week.

How should Typology products containing glycolic acid be used?

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

• The exfoliating serum : This daily-use serum targets blackheads and enlarged pores, for a smooth, even complexion. Formulated with 10% glycolic acid, it also contains ingredients with soothing, anti-inflammatory, and restorative properties, such as bisabolol and chamomile extract. After makeup removal and a thorough cleansing, apply 3 to 4 drops of serum to your face, then gently massage for a few moments to allow the actives to penetrate. This treatment does not require rinsing, but this is not always standard with glycolic acid products, so it is important to always read the suppliers' instructions carefully.

• The peeling mask : This treatment combines the action of 4 AHAs and a PHA to work at different depths of the epidermis and remove dead skin cells. This mask-gel is applied once or twice a week for ten minutes before being rinsed off.

• The exfoliating night cream : Formulated for daily use, it works day after day to unclog pores, limit their dilation, and prevent blackhead formation.

Some clinics and dermatologists offer glycolic acid peel sessions to diminish wrinkles, correct imperfections and pigmentation spots, and restore the skin’s radiance.

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 indicated. It is also at this time that they select the glycolic acid concentration (typically between 20% and 70% in a clinical setting versus 4% to 10% in cosmetic products) and the exposure duration. The physician explains the protocol, answers questions, and provides a detailed estimate. A preparatory skin phase is often recommended, with daily application of a cream containing a low concentration of glycolic acid for about fifteen days to optimize exfoliation.

The peeling session itself is relatively simple and quick : after a thorough facial cleansing, the practitioner applies the glycolic acid solution with a brush or compress. The contact time is short – typically 2 to 5 minutes – but may be accompanied by a tingling or warming sensation. A neutralizing solution is then applied to stop the acid’s action, before rinsing and soothing the skin with a moisturizing cream. Each session lasts about 20 minutes, requires no social downtime, but strict sun protection (SPF 30 minimum) 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 dermatologic procedure, the peel with glycolic acid does not suit everyone. It is not recommended in cases of pregnancy, breastfeeding, known allergies, active skin lesions, or infection. Taking photosensitizing medications also constitutes 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).