Skin Atlas
Definition & Application
An archive of mapped terms.
Classified within the context of modern skincare.
Comedogenicity: When Ingredients Clog Pores
Comedogenicity describes a cosmetic ingredient's tendency to promote the formation of comedones. Those prone to blackheads and blemishes benefit from understanding this concept – and its limitations.
TABLE OF CONTENTS
What is comedogenicity?
Comedogenicity is a property of cosmetic ingredients that describes how strongly a substance can promote the formation of comedones. Comedones form when sebaceous gland follicles become clogged with sebum, dead skin cells, and environmental particles. If the resulting plug oxidizes on the surface, it is called an open comedone (blackhead); if it remains covered, it is a closed comedone. This concept serves as a guide for product selection – but does not replace individual observation of one's own skin.
How does comedogenicity affect the skin?
Comedogenic ingredients can constrict follicle openings and promote the formation of blockages. This primarily occurs when highly occlusive substances are used in high concentrations on blemish-prone skin. Certain waxes, butters, and highly saturated fats are considered potentially pore-clogging – but always depending on the dosage and overall formulation.
Light textures such as squalane formulations or glycerin-based humectants burden the pores significantly less. Important: Squalane (saturated hydrocarbon) is not the same as squalene – oxidized squalene can be comedogenic, as demonstrated by Chiba et al. (2000).
Measurement and evaluation
Historically, comedogenicity was assessed using the rabbit ear assay on a scale of 0 to 5, as established by Kligman (1979). However, this method has limited transferability to human skin. Modern assessments consider formulation context, concentration, vehicle matrix, and individual skin condition.
Therefore, lists of "comedogenic vs. non-comedogenic" should only be understood as a rough guide. An ingredient with a high rating does not necessarily cause problems in low concentration – and vice versa.
Comedogenicity lists are a starting point, not a judgment: The overall formulation and individual skin type determine whether a substance actually clogs pores.
Application and tolerability
Whether a product causes blemishes depends on several factors: skin type, dosage, overall formulation, and frequency of use. Even products officially declared non-comedogenic can cause problems if overused or in an unfavorable matrix.
Recommendations for blemish-prone skin:
- Textures: Prefer light fluids and serums; use highly occlusive products sparingly.
- INCI transparency: Pay attention to clear ingredient declarations; squalane-based formulations are well-tolerated by many skin types.
- Patch test: Introduce products gradually and observe reactions; a controlled test on a small area helps to detect intolerances early.
Comedogenicity and other active ingredients
In combination with exfoliating active ingredients such as BHA (Beta-Hydroxy Acids), the risk of pore constriction can be reduced – BHA dissolves excess dead skin cells and sebum, keeping follicles clear. Retinoids support cell renewal and can reduce the formation of comedones in the long term. Both active ingredients should be introduced slowly on sensitive skin.
Moisturizing ingredients such as glycerin or hyaluronic acid are largely considered harmless in terms of comedogenicity and can be easily combined with other active ingredients.
For whom is comedogenicity relevant?
This topic is particularly relevant for people with oily, blemish-prone, or acne-prone skin. For dry or normal skin, it plays a minor role, as sebum production and pore activity are lower. Those prone to blackheads should pay attention to the formulation when choosing products and use their skin's individual reaction as a guide.
Frequently asked questions about comedogenicity
Does a high comedogenicity rating mean that a product will always cause blackheads?
No. The value of a single ingredient is only a guide. The actual effect depends on concentration, overall formulation, and individual skin type. Even substances with a high rating can be well-tolerated in low doses.
Is comedogenicity synonymous with pore clogging?
Not quite. Comedogenicity describes a substance's potential to promote comedones – pore clogging is the possible result. Cleansing routine, skincare layering, and individual skin biology influence whether it actually occurs.
How do I know if a product is comedogenic for my skin?
A controlled patch test helps: Apply the product to a small area for several days and observe the reaction. If new blemishes appear, the product may be a contributing factor.
Conclusion
Comedogenicity is a useful guide when choosing skincare products, especially for blemish-prone and blackhead-prone skin. However, rigid lists do not replace individual observation: formulation context, dosage, and personal skin biology ultimately determine whether a product promotes comedones or not. Those who keep comedogenicity in mind and opt for light textures create a good foundation for clear skin.
References
- Kligman AM. Improved rabbit ear model for assessing comedogenicity (1979)
- Chiba K. Comedogenicity of squalene monohydroperoxide (2000)
- JAAD Reviews (2025): Comedogenicity in Cosmeceuticals – Overview & Limitations
