TL;DR
- Harsh cleansing is wrong for most people — not foaming cleansers specifically, and not any single ingredient on its own
- Sodium lauryl sulphate (SLS) is a well-established irritant; other sulphates like SLES are generally milder — overall formulation matters more than any one ingredient
- A tight, squeaky feeling after washing often reflects excessive cleansing and lipid removal, though some people associate this sensation with feeling clean
- Not everyone needs to cleanse twice daily — many people with dry skin, rosacea, or eczema do well with water only in the morning and cleanser at night
- A good cleanser removes what needs removing without stripping what should stay
The cleanser is usually the least glamorous step in a skincare routine. It is also, for many people, the step doing the most underappreciated work — or, when the wrong product is used too aggressively, the most underappreciated damage.
What cleansing actually does
Cleansing removes surface debris — dead cells, sebum, sunscreen, makeup, environmental residue — to prepare the skin for what follows. The goal is selective removal: take off what should come off, leave intact the barrier lipids and water-retaining factors that should stay.
A cleanser that achieves this is doing its job well. A cleanser that leaves skin feeling tight or uncomfortable after washing often reflects excessive cleansing and lipid removal — though it is worth noting that some people associate this tight sensation with feeling properly clean, and tolerance for it varies. The more reliable signal is how your skin feels an hour later, not immediately after rinsing.
The sulphate question — with nuance
Sodium lauryl sulphate (SLS) is a well-established irritant, commonly used in dermatological research specifically to induce irritant contact dermatitis in study models. It is a genuinely harsh surfactant.
Sodium laureth sulphate (SLES) is a different and generally milder compound, despite the similar name. Whether a cleanser containing SLES is irritating depends on concentration, the overall surfactant blend, buffering, contact time, and formulation — not simply on whether SLES appears on the ingredient list. Treating all sulphates as equivalently harsh risks an oversimplified ingredient-blacklist approach that doesn’t reflect how formulation chemistry actually works. Overall formulation matters more than any single ingredient.
Repeated use of genuinely harsh cleansers may contribute to dryness and irritation over time, particularly for people who already have a compromised barrier or conditions like eczema or rosacea. Healthy skin has continuous and fairly rapid barrier recovery capacity, so this isn’t a catastrophic effect for everyone — but it is a real one for those more susceptible.
Foam is not the enemy
The amount of foam a cleanser produces does not reliably predict its gentleness or cleansing effectiveness. Many excellent, dermatologist-recommended gentle cleansers do foam — foaming agents and gentle formulation are not mutually exclusive. The relevant question is not whether a cleanser foams, but whether it cleanses without leaving skin feeling tight or uncomfortable afterward.
What to look for
A good cleanser for most people: cleanses without leaving the skin tight or uncomfortable; has a mildly acidic pH, broadly in the range of 5–6, though the evidence that small pH differences within this range meaningfully change outcomes is limited; uses a well-balanced surfactant blend — glucosides and betaines are commonly used milder options, though a well-formulated sulphate-containing cleanser can also be perfectly gentle.
Micellar water is a reasonable option for light cleansing, particularly for minimal makeup. Some people tolerate it best when it is rinsed off rather than left on the skin, as residue can itself cause irritation in sensitive individuals.
Double cleansing — an oil-based cleanser first to dissolve SPF and makeup, followed by a water-based cleanser — is an effective approach for removing heavy products without requiring harsh surfactants to dissolve oil in a single step. It is a practical option for anyone wearing SPF and makeup daily, not a requirement for everyone.
Not everyone needs to cleanse twice daily
This is worth saying plainly: twice-daily cleansing is a convention, not a universal requirement. Many people — particularly those with dry skin, rosacea, or eczema — do well with water only in the morning and a cleanser at night, when removing the day’s accumulated sunscreen, makeup, and environmental residue is often most important. Oily or acne-prone skin, by contrast, may genuinely benefit from a more thorough cleanse, including a stronger surfactant or an active ingredient like salicylic acid, and shouldn’t default to the gentlest possible option simply because gentle is generally a good default. Skin type and individual tolerance should guide the choice, not a one-size-fits-all routine.
⚠️ Clinical note: The principle here is harsh cleansing is wrong for most people — not foaming cleansers, and not any single ingredient in isolation. Formulation, concentration, and individual skin type and tolerance matter more than whether a product foams or contains a particular sulphate.
Sources
- Gloor M, Wasik B, Gehring W, Grieshaber R, Kleesz P, Fluhr JW. On the course of the irritant reaction after irritation with sodium lauryl sulphate. Skin Res Technol. 2004;10(3):144–152. doi:10.1111/j.1600-0846.2004.00074.x
- Frosch PJ, Kligman AM. The sodium lauryl sulfate model: an overview. In: van der Valk PGM, Maibach HI, eds. The Irritant Contact Dermatitis Syndrome. Boca Raton: CRC Press; 1996:199–206. [SLS as most widely used irritant contact dermatitis model.]
- Agner T, Damm P, Skouby SO. Subclinical, non-erythematous irritation with an open assay model (washing): sodium lauryl sulfate (SLS) versus sodium laureth sulfate (SLES). Exog Dermatol. 2001;1:19–23. doi:10.1159/000049985 [Pronounced reaction to SLS; far milder to SLES.]
- Löffler H, Happle R. Profile of irritant patch testing with detergents: sodium lauryl sulfate, sodium laureth sulfate and alkyl polyglucoside. Contact Dermatitis. 2003;48(1):26–32. doi:10.1034/j.1600-0536.2003.480106.x [APG minimal irritation; SLES milder than SLS.]
- Fluhr JW, Darlenski R, Surber C. Glycerol and the skin: holistic approach to its origin and functions. Br J Dermatol. 2008;159(1):23–34. doi:10.1111/j.1365-2133.2008.08643.x [Skin barrier lipid and humectant context for cleansing.]
- Proksch E, Brandner JM, Jensen JM. The skin: an indispensable barrier. Exp Dermatol. 2008;17(12):1063–1072. doi:10.1111/j.1600-0625.2008.00786.x [Barrier recovery capacity in healthy skin.]
- Lambers H, Piessens S, Bloem A, Pronk H, Finkel P. Natural skin surface pH is on average below 5, which is beneficial for its resident flora. Int J Cosmet Sci. 2006;28(5):359–370. doi:10.1111/j.1467-2494.2006.00344.x [Skin surface pH reference; optimal range for barrier enzyme function.]
