Salicylic Acid (BHA) for Blemish-Prone Skin: Effects, Risks and Why Cosmenia Relies on AHA

September 2, 2026

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Written by Cosmenia

Note: image partly or fully created with AI.

The short answer

Salicylic acid (BHA) is oil-soluble, so it penetrates into the pores, dissolves sebum and dead skin cells there and has an anti-inflammatory effect – which is why it is considered one of the most effective ingredients against blackheads and blemish-prone skin. Studies show reductions in comedone density of up to 40% after four weeks. The catch: it can trigger a so-called purging phase at the beginning and makes the skin more sensitive to light.

What is salicylic acid?

Salicylic acid is a beta hydroxy acid (BHA) that was originally obtained from willow bark but is mostly produced synthetically today. Unlike water-soluble AHA fruit acids, BHA is oil-soluble – and that is its key advantage: it can pass through the oily sebum in the pore and work directly where blackheads and blemishes form.

How does salicylic acid work on blemish-prone skin?

Deep pore cleansing: It loosens the bonds between dead skin cells and excess sebum in the pore and helps to gently clear them.
Anti-inflammatory effect: As a relative of acetylsalicylic acid (aspirin), it inhibits the enzyme cyclooxygenase (COX), reducing inflammatory messengers – which explains its de-swelling effect on red spots.
Prevention: With regular use, it keeps pores clearer and can help prevent new blemishes.

A critical look: purging, irritation and light sensitivity

Salicylic acid has a reputation as a miracle cure – the reality is more nuanced. In the first two to six weeks of use, the skin can initially get worse before it gets better: the so-called purging phase, in which deep-seated congestion is brought to the surface. Many users give up on the product in disappointment during exactly this phase. If the worsening lasts longer than about six weeks, it is usually no longer purging but a genuine irritation reaction.

In addition, BHA noticeably increases the skin's sensitivity to light, so consistent sun protection is a must during use. On sensitive or already weakened skin barriers, the exfoliating effect can also lead to dryness and additional irritation – a contradiction when the actual goal is calmer, clearer skin.

Why Cosmenia's Clear Skin Set relies on AHA instead of BHA

Instead of oil-soluble BHA, The Facial Cleanser relies on AHA fruit acids – water-soluble acids that work on the skin's surface rather than penetrating deep into the pore. This makes cleansing milder and better suited to everyday use, without giving up the exfoliating, clarifying effect. For many people with mild to moderately blemish-prone skin, this gentler route is enough – without taking on the irritation and purging risk of BHA.

In the Clear Skin Set, this is complemented by The Glowy Gel with aloe vera and zinc, which additionally regulates sebum production – a principle that overlaps thematically with BHA's effect on the sebaceous glands but is considerably less irritating. The Hyaluronic Toner with chamomile provides soothing and moisture between the steps so that the barrier stays stable despite cleansing.

Who can still benefit from salicylic acid?

If you already have experience with acids, have a resilient skin barrier and want to target stubborn blackheads, you can benefit from BHA – ideally introduced slowly at a low frequency and combined with a hydrating, barrier-supporting routine. For sensitive, irritated or already weakened skin, the milder AHA route is usually the more sustainable choice.

Frequently asked questions about salicylic acid

Is it normal for skin to get worse at first?

Temporary purging for two to six weeks is normal. If it lasts longer, it is probably an irritation reaction rather than a clearing phase – in that case, you should pause use.

Can I combine salicylic acid with AHA?

Generally yes, but not both at high concentrations at the same time – that increases the risk of irritation unnecessarily. A mild AHA cleanser like The Facial Cleanser can usually be combined well with a separate BHA product on other days.

Why doesn't Cosmenia use salicylic acid?

Because the focus is on a routine that is as low in irritation and as suitable for everyday use as possible, one that sensitive and blemish-prone skin can both tolerate – without a purging phase and without additional light sensitivity.

Conclusion

Salicylic acid is scientifically well documented and effective against stubborn blackheads – but not without risks such as purging and increased light sensitivity. If you want to tackle blemishes in a targeted but less irritating way, Cosmenia's Clear Skin Set with AHA cleansing, sebum-regulating zinc and soothing hydration offers a gentler alternative.