Skincare Guide - Comedogenicity
Comedogenicity – its meaning and impact on the skin
Comedogenicity describes a substance's tendency to promote comedones (blackheads and whiteheads) by clogging pores with sebum and dead skin cells. The term serves as a guideline for whether a product is suitable for blemish-prone skin.
How do comedones develop?
When sebum, corneocyte debris, and dirt accumulate, plugs form in the follicles. If the plug oxidizes on the surface, an open comedo (blackhead) develops; if it remains covered, it is called a closed comedo.
Measurement and limits
Historically, comedogenicity ratings were determined using the rabbit ear assay (scale 0–5). This method is useful but has limited applicability to human skin. Modern assessments consider formulation, concentration, matrix, and individual skin condition. Therefore, "comedogenic vs. non-comedogenic" lists should only be considered a rough guide.
Examples – what is considered in practice
- Carriers considered to be less pore-clogging : light esters, squalane-based textures, humectants (e.g., glycerin). Note: Squalane ≠ squalene; oxidized squalenes can be comedogenic.
- Potentially occlusive/high-fat components : certain waxes/butters and highly saturated fats can – depending on the dose and formulation – promote the formation of comedones.
Individual reaction & formulation logic
Whether a product triggers breakouts depends on skin type, dosage, overall formulation, and usage. Even "non-comedogenic" products can cause problems if overdosed or applied in an unsuitable matrix. Patch testing and gradual introduction help to detect reactions early.
Practical recommendations for skin prone to blemishes
- Light textures (fluids/serums), do not apply overly occlusive layers.
- Pay attention to clear INCI and a balanced lipid matrix; squalane-based formulations are often well tolerated.
- Routine: gentle cleansing, avoid overly aggressive degreasing; if necessary, integrate active ingredients such as BHA or retinoids after consulting a doctor.
Conclusion
Comedogenicity is a useful guideline, but it does not replace individual observation. Current assessments emphasize the formulation context and skin biology; rigid lists alone are not sufficient for decision-making.