Which active ingredients can be combined with salicylic acid?

It is quite common to combine salicylic acid and zinc to formulate treatments aimed at oily or blemish-prone skin. Indeed, zinc, whether in the form of zinc gluconate or zinc PCA, is an astringent, mattifying agent capable of limiting the proliferation of bacteria Cutibacterium acnes, which, as their name suggests, play a role in acne. Furthermore, zinc exhibits an anti-inflammatory action, arising from its regulatory effect on the release of certain pro-inflammatory cytokines, such as interleukin-1. It is therefore particularly useful for soothing inflammatory lesions of acneic origin.

Combining zinc with salicylic acid strengthens their respective purifying actions while engaging several complementary mechanisms. Salicylic acid works both at the surface and in depth to exfoliate the epidermis, unclog pores and soothe inflammation. Zinc supports this action through its mattifying and soothing properties.

The combination of salicylic acid with retinoids, such as retinol, retinal or synthetic retinoids like adapalene, is regularly considered in treatments for acne-prone skin. These two actives indeed target complementary mechanisms: salicylic acid exfoliates the superficial layers of the skin and unclogs pores thanks to its lipid solubility, while retinoids regulate keratinocyte differentiation and stimulate deep cellular renewal. Their combination could allow for a combined action against blackheads, open or closed comedones and hyperkeratinisation.

The combination of salicylic acid and a retinoid could also act on signs of photoageing. This is suggested by a study conducted by Draelos et al. in 2016. It compared the efficacy of 0.25% retinol and 0.25% tretinoin when applied immediately after a 30% salicylic acid peel. Twenty women underwent two sessions, two weeks apart, during which each half of the face received one of the two retinoids, followed by the peel application. Double-blind assessments by investigators and the participants themselves showed that, after four weeks, both protocols significantly improved pore size, skin texture and overall appearance. According to the investigators’ assessments, tretinoin demonstrated slightly greater efficacy than retinol, but the study concluded that either retinoid can be safely used after a salicylic acid peel to reduce signs of photoageing.

However, it is recommended to exercise caution when using this combination, particularly for sensitive skin.

Retinoids and salicylic acid can be irritating, particularly during initial use. To limit side effects, it is preferable to not introduce them simultaneously into your skincare routine and to apply them at different times (for example, you can use salicylic acid in the morning and retinol in the evening). Finally, if you are undergoing oral isotretinoin treatment, it is generally recommended to avoid the concurrent use of salicylic acid, so as not to further compromise the skin barrier.

Note: If you are undergoing a topical retinoid-based dermatological treatment for acne, it is advisable to consult your dermatologist directly to determine whether salicylic acid can be used. For example, the combined use of salicylic acid and adapalene is often contraindicated.

Salicylic acid can also be combined with benzoyl peroxide to care for acne-prone skin. Each acts via a distinct mode of action: benzoyl peroxide is chiefly valued for its potent antibacterial properties, which enable it to significantly reduce the proliferation of Cutibacterium acnes, whereas salicylic acid exfoliates blocked pores and limits the accumulation of sebum and dead cells responsible for comedones. This combination therefore acts on both the bacterial cause of acne and its keratinous component.

The risk of irritation is not insignificant when benzoyl peroxide and salicylic acid are combined. If you wish to use both active ingredients, introduce each gradually into your skincare routine.

Two studies, presented in the table below, investigated this association and achieved favourable clinical outcomes with few adverse effects. They were not limited to the combination of salicylic acid and benzoyl peroxide, but also evaluated other active ingredient combinations, thus broadening the prospects for use.

The azelaic acid and salicylic acid display complementary modes of action that are particularly advantageous for skin prone to blemishes or redness. Azelaic acid is recognised for its antibacterial, anti-inflammatory and mattifying effects, whereas salicylic acid acts primarily as a keratolytic agent, facilitating the removal of dead skin cells and unclogging pores. By combining these two actives, it may be possible to simultaneously target inflammation, the bacteria responsible for acne and comedones. This combination could also benefit skin exhibiting a couperose mild or diffuse redness, with azelaic acid often recommended to even out the complexion.

A trial carried out on 34 patients with mild to moderate acne evaluated the effect of four peel sessions performed at two-week intervals. A combined solution of 20% salicylic acid (SA) and 20% azelaic acid (AA) was applied to one half of the face, while the other half received a 25% trichloroacetic acid (TCA) peel. Clinical assessments demonstrated a more rapid improvement in inflammatory lesions on the SA/AA-treated side, and in non-inflammatory lesions on the TCA-treated side. By the end of the four sessions, both treatments achieved significant improvement with no marked difference between them, although participants expressed a preference for the SA/AA side, which was regarded as more comfortable.

The combination of salicylic acid and glycolic acid, an AHA, is often highlighted in exfoliating products because these two molecules act in a complementary manner on cellular renewal. The blend of glycolic and salicylic acids harnesses the combined properties of both actives. Lipophilic salicylic acid readily penetrates pores to clear them and reduce the formation of blackheads and comedones, while glycolic acid removes dead skin cells from the surface and accelerates cell turnover. Combining glycolic and salicylic acids could therefore effectively smooth the skin, diminish pigmented spots and prevent pore blockage.

A study was conducted to evaluate the efficacy of a serum combining glycolic acid and salicylic acid. Sixty-six patients aged 17 to 46 with mild to moderate inflammatory acne applied this serum nightly for two weeks. The results show that more than 90% of participants observed a marked improvement in their acne, with fewer comedones and cystic lesions, while 70 to 80% reported less oily, more even-toned skin.

Although highly efficacious, this combination is not recommended for sensitive skin.

Note: To minimise any irritation, it is advisable to alternate the use of glycolic acid and salicylic acid serums (for example, every other day) rather than mix or layer them. Furthermore, one should not try to substitute for professional formulators, who are skilled not only in the compatibility of active ingredients but also of the other components in a cosmetic formula (film-forming agents, surfactants, preservatives, solvents, texture agents...).

The association between lactic acid and salicylic acid is quite similar to that between salicylic acid and glycolic acid. Indeed, lactic acid also belongs to the AHA family and has exfoliating properties. The main difference from glycolic acid lies in its greater molecular weight, which results in a more superficial yet gentler action. Furthermore, lactic acid enhances the natural moisturising factor (NMF), a group of amino acids in the stratum corneum that help to hydrate the skin. The combination of salicylic acid and lactic acid is noteworthy because it merges the keratolytic and pore-unclogging effects of BHA with the hydrating and mild exfoliating properties of AHA. It may, for example, be beneficial for combination skin with dry areas as lactic acid partly offsets the potentially drying effect of salicylic acid.

Note: To date, no clinical study has tested this combination. Nevertheless, researchers have formulated a microemulsion comprising 12% salicylic acid and 4% lactic acid and assessed its stability through a series of experiments. The next step will be to evaluate its efficacy.

Combining hyaluronic acid with salicylic acid could help to offset the drying effect that BHA can sometimes cause. The hyaluronic acid, thanks to its high hygroscopic capacity, intensely hydrates the uppermost layers of the epidermis and helps maintain skin suppleness. This synergy is particularly beneficial for combination or oily skin which wish to benefit from the purifying action of salicylic acid without compromising their hydrolipidic barrier. Although salicylic acid and hyaluronic acid are rarely formulated together in a single product, they frequently coexist within the same skincare routine.

Although the benefits of this combination have not been formally tested, there is no contraindication to using salicylic acid and hyaluronic acid together.

Combining salicylic acid and tranexamic acid could be relevant for skin prone to pigmented spots or an uneven complexion. Salicylic acid, owing to its exfoliating and keratolytic action, encourages the removal of dead cells and enhances the penetration of depigmenting actives. Tranexamic acid, for its part, regulates melanin production and curbs the inflammation that drives hyperpigmentation. It is reasonable to suppose that salicylic acid and tranexamic acid could act synergistically to prevent or diminish post-inflammatory hyperpigmentation or brown spots in general.

In the absence of clinical studies on the subject, the potential synergy between salicylic acid and tranexamic acid remains hypothetical.

The combination of salicylic acid and vitamin C is primarily aimed at evening out skin tone and enhancing the skin’s radiance. Salicylic acid exfoliates the skin, allowing vitamin C, in the form of ascorbic acid or one of its derivatives, to penetrate more deeply and exert its antioxidant and brightening effects. Using vitamin C and salicylic acid together may help achieve smoother skin and a more uniform complexion. However, if you use pure vitamin C, we advise caution. Indeed, this active ingredient can cause irritation in sensitive skin due to its very acidic pH. Salicylic acid can also be somewhat drying, so it is wise to proceed with care if your skin is sensitive.

A study evaluated the efficacy of a 30% salicylic acid peel combined with vitamin C mesotherapy to manage melasma in 50 female patients divided into two groups. All participants received a peel every two weeks for two months, while one group additionally received vitamin C injections into the lesions. The six-month follow-up demonstrated a significant reduction in the MASI (Melasma Area and Severity Index) score, reflecting a clinical improvement in brown spots. The treatment was well tolerated, with only a mild burning sensation reported as a side effect.

The combination of salicylic acid and niacinamide is particularly interesting for oily skin prone to acne or redness. Salicylic acid, through its keratolytic and anti-inflammatory action, helps to clear pores and reduce blemishes, while niacinamide reinforces the skin barrier and soothes inflammation. Combining niacinamide with salicylic acid allows for both exfoliation and barrier reinforcement, two effects that are often at odds.

Aside from the studies presented above that demonstrated the benefits of combining salicylic acid, niacinamide and benzoyl peroxide, one investigation focused on a cleanser containing 0.45% salicylic acid, 1% gluconolactone, 2% niacinamide and three types of ceramides (EOP, NP and AP). 43 individuals with oily, acne-prone skin and 39 with sensitive skin were recruited to use the cleanser daily. After four weeks, a significant reduction in the number of inflammatory and non-inflammatory lesions, as well as a marked decrease in sebum production, were observed in the first group. Moreover, no side effects were reported in either the acne group or among those with sensitive skin.

Some individuals associate salicylic acid with aloe vera gel. Derived from the plant of the same name, it is renowned for its hydrating properties, owing to its richness in hygroscopic amino acids, and for its soothing qualities. Aloe vera gel is often used to alleviate tightness and sensations of skin discomfort. It could therefore counterbalance the potentially irritating effects of salicylic acid. Aloe vera and salicylic acid are rarely present in the same formulation but, as with hyaluronic acid, there are no contraindications to using both in a skincare routine.

Finally, some formulations combine salicylic acid with tea tree essential oil to tackle persistent blemishes. Whilst salicylic acid promotes cell turnover and unclogs skin pores, thereby limiting comedone formation, tea tree essential oil targets the bacteria C. acnes, responsible for inflammatory breakouts. Their combined use couples an exfoliant with an antibacterial agent, enhancing their respective anti-acne effects. The pairing of salicylic acid and tea tree oil is also found in certain anti-dandruff shampoos. Tea tree essential oil indeed has antifungal properties against the yeasts Malassezia, whose proliferation is partly responsible for the onset of dandruff.

Important: Do not add tea tree essential oil to a formulation that already contains salicylic acid. A skincare product can contain both actives if properly formulated. However, adding this oil yourself to an existing product may cause irritation and redness if dosed incorrectly.

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