Salicylic acid is the most widely used beta hydroxy acid in skincare and the one most sought after by people dealing with oily skin, clogged pores, and blemishes.
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What is salicylic acid used for?
Salicylic acid helps clear pores from within. Unlike other exfoliants, it is oil-soluble: it enters the pore, mixes with sebum, and dissolves the buildup. On the surface, it promotes the shedding of dead skin cells, making the skin’s texture more even. It is therefore especially useful for blackheads, enlarged pores, shiny skin, and recurring blemishes, and it also plays a role in addressing the dark marks left behind after a blemish.
This is the characteristic that distinguishes it from all other acids: the others work on the surface, while salicylic acid reaches where the problem begins.
It is often combined with niacinamide, which supports the function of skin cells. Since salicylic acid is effective but can be drying, using the two active ingredients together is often the best approach: we discuss this in the article dedicated to niacinamide and salicylic acid for acne-prone skin.
What is salicylic acid?
Salicylic acid is an organic compound belonging to the carboxylic acid family, originally isolated from willow bark — hence its name, from the Latin Salix. It is used in several fields, and in cosmetics it is one of the most widely used active ingredients in products for blemish-prone skin.
Its key property is its keratolytic action: it promotes the shedding of cells from the stratum corneum, helping keep pores clear.
It can be found in many different forms: cleansers, toners, serums, and peels, with concentrations that vary greatly depending on the type of product.
A useful clarification: salicylic acid also appears in pharmaceutical preparations, at much higher concentrations and for medical purposes. In cosmetics, lower percentages are used, with the aim of improving the appearance of the skin. For moderate or severe acne, a dermatologist remains the point of reference.
Difference between BHA and AHA
When discussing chemical exfoliants, there are two main families: beta hydroxy acids (BHAs) and alpha hydroxy acids (AHAs).
Salicylic acid is a beta hydroxy acid: this means that the molecule’s hydroxyl group is separated from the acid group by two carbon atoms, whereas in an alpha hydroxy acid—such as mandelic acid—it is separated by only one.
The practical consequence is this: AHAs are water-soluble and work mainly on the surface, whereas salicylic acid is oil-soluble and can therefore enter the pore, where it mixes with sebum and dissolves blockages. This is why it is the active ingredient of choice for blackheads and clogged pores.
The BHA family also includes betaine salicylate and willow bark extract, which are gentler alternatives. The complete overview of chemical exfoliants can be found in the guide to AHA, BHA, and PHA.
The main benefits of salicylic acid
Salicylic acid’s function is to exfoliate the skin, and its effects stem from this:
- Deeply cleanses pores: as it is oil-soluble, it penetrates the pore to exfoliate its lining, remove excess sebum, and dissolve blockages.
- Helps prevent new blemishes: by keeping pores free of sebum and dead skin cells, it counteracts the formation of comedones.
- Exfoliates and smooths: on the surface, it promotes the removal of dead skin cells, improving texture and smoothness.
- Makes pores less noticeable: its ability to deeply cleanse pores helps them appear smaller.
- Helps control excess sebum: it helps rebalance the skin’s shiny appearance.
- Reduces the appearance of redness: it helps make the redness that accompanies blemishes less noticeable.
- Reduces the appearance of post-blemish marks: it helps lighten the red and brown spots that remain after breakouts, and is also used for hyperpigmentation and photodamage.
What concentration of salicylic acid should be used
It is the question that almost no one answers with numbers, yet in Europe percentages are not at the formulator's discretion: they are set by law.
Regulation (EC) 1223/2009 on cosmetic products places salicylic acid in Annex III, entry 98, meaning among substances subject to restrictions. These are the maximum limits.
| Product type | Maximum concentration |
|---|---|
| Rinse-off hair products | 3% |
| Other products (face, serums, peels) | 2% |
| Body lotions, eye and lip products | 0,5% |
| As a preservative (Annex V) | 0,5% |
There is also a restriction worth knowing if there are young children at home: salicylic acid cannot be used in products intended for children under three years of age.
When you read “2% salicylic acid” on a facial serum, you are reading the maximum permitted limit, not an extraordinary percentage. And a higher concentration is not legally permitted in a cosmetic product: if a product claims otherwise, either it is not a cosmetic or it is non-compliant.
Why pH matters as much as the percentage
Two products with the same percentage of salicylic acid can perform very differently, and the reason is the formula's pH.
Salicylic acid works in its free acid form. In an overly alkaline environment, the molecule is predominantly found in a salt form, which does not pass through the pore's sebum in the same way. This is why exfoliating formulas have a controlled, slightly acidic pH, and why a highly alkaline cleanser reduces the effectiveness of the acid it contains.
It is not information that appears on the label, but it explains why it is worth choosing products formulated by people who understand the issue, rather than looking only at the stated percentage. We have a dedicated article on how the skin's pH works.
How to use salicylic acid
The most suitable concentration varies from person to person, and it is advisable to consult your dermatologist or trusted pharmacist before starting, especially in the presence of significant acne.
In general, it should be used sparingly but consistently. The key is to listen to your skin: if slight irritation appears, it is best to stop for a day or two and moisturize thoroughly. Always follow the product instructions.
The main unwanted effect of salicylic acid is its ability to irritate and dry out the skin of those who are particularly sensitive or use it excessively: peeling, dryness, and redness may occur. When starting, it is better to use it every other day to assess how the skin reacts. It is also not recommended during pregnancy or breastfeeding without medical advice.
As an active ingredient that acts on skin renewal, it is important not to neglect daily sun protection during treatment.
What not to combine salicylic acid with
Salicylic acid works well with almost everything, but there are three situations in which it is better to alternate rather than layer.
With retinol: both accelerate skin renewal, and using them on the same evening increases the risk of irritation without multiplying the results. It is better to use them on alternate evenings. With other exfoliating acids, AHA or PHA: the same principle applies—you choose which one to use that evening. With pure, highly concentrated vitamin C, due to pH and tolerability: if both are needed, apply vitamin C in the morning and salicylic acid in the evening.
Salicylic acid cleansing mousse: Cleansing Active
At LeLang, we specialize in creating products tailored to the needs of every skin type, including sensitive skin, and tested for efficacy. Cleansing Active Mousse is the purifying mousse with anti-imperfection action that respects the skin’s balance.
Contains 0.5% Salicylic Acid, which deeply cleanses the skin by removing impurities and dead skin cells. Thanks to ingredients such as Burdock, Tea Tree Oil, and Betaine, which enhance its purifying power, Cleansing Active remains gentle and soothing at the same time.
CLEANSING ACTIVE MOUSSE Purifying face cleansing mousse anti-imperfections Reduce enlarged pores Purifies the skin from impurities Improves ... Discover CLEANSING ACTIVE MOUSSE
The synergistic action of the ingredients exfoliates and purifies without altering the skin’s state of health. It is the ideal solution for incorporating a salicylic acid cleanser into your routine: effective yet gentle. Suitable for those with acne-prone, oily, or combination skin, especially if you want to brighten dull, lackluster skin and stimulate cell turnover. Prolonged use is not recommended for dry or very dry skin.
In the salicylic acid ingredient page, you’ll find the complete list of LeLang formulas that contain it, while the dedicated collection features other products designed for blemish-prone skin.
Frequently asked questions about salicylic acid
What is salicylic acid used for on the face?
It helps keep pores clear. Because it is oil-soluble, it enters the pore, dissolves sebum buildup, and helps loosen the dead skin cells that clog it. On the face, this translates into fewer blackheads, less visible pores, less shine, and a more even texture. It also helps reduce the dark marks left by blemishes that have already healed.
How often should salicylic acid be used?
It depends on the product format. In a cleanser, which stays on the skin for only a few seconds, it can be used every day. In a serum or toner, which remain on the skin, it’s best to start every other day and increase use only if your skin responds well. With a higher-concentration peel, use it once or twice a week.
What concentration of salicylic acid should I choose?
In cosmetics, typical concentrations range from 0.5% to 2%, which is also the legal maximum for facial products. Lower concentrations, around 0.5%, are used in daily cleansers and for more reactive skin; 2% is the upper limit for leave-on products. A higher concentration does not mean better results: it only means a greater risk of irritation, and on a stressed skin barrier the effect is counterproductive.
Can salicylic acid be used every day?
Yes, if it’s in a low-concentration cleanser and your skin tolerates it. No, if it’s a serum or peel: in that case, daily use quickly leads to dryness and redness. The warning sign is always the same: skin that feels tight, stings when you apply moisturizer, or suddenly becomes shinier.
Should I stop if I get more pimples at first?
It’s the most common question during the first few weeks. An active ingredient that accelerates skin renewal can bring existing blockages in the pore to the surface before they become visible: the process tends to resolve within four to six weeks and affects the areas where blemishes usually appear. If lesions appear in new areas, or two months pass without improvement, then it isn’t an adjustment period: it’s best to stop and reassess your routine.
Can salicylic acid and niacinamide be used together?
Yes—and it’s actually one of the most sensible combinations for blemish-prone skin: salicylic acid works on the pore, niacinamide supports the barrier and reduces redness, balancing the acid’s tendency to cause dryness. The old rule that they were incompatible is not supported by current cosmetic formulations.
Can people who are allergic to aspirin use salicylic acid?
The acetylsalicylic acid in aspirin and salicylic acid are related molecules, and anyone with a known sensitivity to salicylates should speak with their doctor before using products that contain them, even at low concentrations. It’s a precaution that concerns few people, but is rarely mentioned.
Should salicylic acid be used in the morning or evening?
Evening is better for leave-on products, so your skin can renew itself overnight without adding sun exposure. Cleanser can be used either morning or evening. In both cases, sun protection the next day is non-negotiable: freshly exfoliated skin is more likely to develop dark spots.
If you don’t know which concentration to start with, or if your skin has reacted badly in the past, it’s the kind of question best resolved in person: LeLang partner pharmacies are trained to assess your skin before recommending an exfoliant.
Sources for this article
01 Regulation (EC) No. 1223/2009 of the European Parliament and of the Council on cosmetic products, Annex III — restricted substances, entry 98 (salicylic acid): 3% in rinse-off hair products, 2% in other products, 0.5% in body lotions, eyeshadows, mascaras, eyeliners, lipsticks, and roll-on deodorants; prohibited in products for children under three years of age, except shampoos.
02 Regulation (EC) No. 1223/2009, Annex V — permitted preservatives: salicylic acid and its salts, maximum concentration 0.5% (calculated as acid).
03 Regulation (EU) No. 655/2013 laying down common criteria for claims relating to cosmetic products.
On the website: guide to AHAs, BHAs, and PHAs · niacinamide · mandelic acid · the skin’s pH · understanding acne · salicylic acid ingredient guide
15-Minute Free Consultation with the Founder
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