Do Clay Masks Really Control Oil? What the Research Says About Kaolin

Clay masks are one of the oldest tricks in oily-skin skincare, yet they are rarely explained with actual evidence. Here is what the research on kaolin really shows, and how often you should reach for one.

Why oily skin reaches for clay in the first place

Oily skin is defined by higher sebum output, and that extra oil is linked with larger-looking follicular openings, more shine and a tendency toward early breakouts. A 2025 cross-sectional study of 200 young women used objective instruments to map these traits and found that oily skin types consistently showed increased sebum, more visible follicular orifices and other surface changes compared with dry or neutral skin (Kuang et al., 2025, PMID 39794411). That is the problem a clay mask is trying to address: not the skin itself, but the surface oil sitting on it.

How kaolin and bentonite work on the surface

Kaolin and bentonite are naturally absorbent clays. Their fine, porous structure lets them adsorb, meaning bind to the surface of, excess oil and loose debris when applied as a mask and then rinsed away. This is a physical surface effect, not a medicine, and it does not change how much oil the skin makes over the long term. Think of a clay mask as a periodic reset for a shiny complexion rather than a permanent fix.

A well-formulated option to try is the Medik8 Natural Clay Mask 75ml, which pairs clay with hydrating and soothing ingredients so the skin feels balanced rather than stripped after rinsing.

What a real clinical assessment found

The most useful recent evidence comes from a 2023 clinical assessment of a specific kaolin-containing clay mask in adults with oily or combination skin. Seventy-five participants used the mask twice weekly for four weeks, with sebum, hydration, barrier function and acne-related surface measures recorded by instruments at baseline and at one, two and four weeks (Zhang et al., 2023, PMID 38009030).

The study reported meaningful points for oily skin:

• Improvements in measured sebum content and in acne-related surface (appearance) measures over the four weeks, as reported in that study.
• Better skin evenness, higher stratum corneum water content and reduced transepidermal water loss, so skin was not left dehydrated.
• Reduced dryness and irritation on tolerance assessment, with high self-reported acceptability.
• No significant change in pore area or porphyrin area, a useful reminder that clay is not a pore-shrinking miracle.

Keep the limits in mind. This was a single four-week study of one particular product in a specific group, so it describes what that mask did under those conditions rather than proving clay works the same way for everyone. It also assessed a different brand than the one linked here, so treat it as supportive context for kaolin masks in general.

How often should oily skin actually use a clay mask?

The clinical study that showed benefit used the mask twice weekly, which is a sensible starting point for most oily and combination skin. More is not better. Because clay works by pulling oil from the surface, over-using it can leave skin feeling tight and can nudge the barrier the wrong way. If your skin feels dry or looks irritated, drop back to once a week.

• Oily or combination skin: up to twice a week is a reasonable ceiling.
• Normal or occasionally shiny skin: once a week, or as a targeted T-zone treatment.
• Dry or sensitive areas: apply only where you are genuinely oily, and rinse before the mask fully hardens.

Getting the most from your mask

Apply to clean skin, leave it on for the time on the pack, and rinse before it cracks, since a bone-dry mask can leave skin feeling stripped. Always follow with a moisturiser to support the barrier, which lines up with the hydration and tolerability findings above. For a straightforward, well-formulated choice, the Medik8 Natural Clay Mask 75ml is an easy one to slot into a weekly routine.

The short version: clay masks like kaolin can genuinely help manage surface oil and keep oily skin looking fresher, the evidence is encouraging but still early, and the goal is balanced skin, not squeaky-clean, over-dried skin.

Disclaimer: This article is for general information only and is not medical advice. The studies cited are from peer-reviewed journals and are provided for educational context. Individual results vary. Speak with a qualified healthcare professional or dermatologist before changing your routine. Verdo Cosmetics makes no therapeutic claims about the products or services mentioned.