What Does Comedogenic Mean?

The term comedogenic comes from the word “comedo,” which is the scientific name for a clogged pore. A comedone can be open (blackhead) or closed (whitehead). When an ingredient is described as comedogenic, it means it has a tendency to block pores, potentially leading to comedones, breakouts, and acne.

Conversely, non-comedogenic ingredients are those that are unlikely to clog pores. Products labelled as non-comedogenic are formulated to minimise the risk of pore blockage, though it is worth noting that this label is not regulated by any official body and varies by market.

How the Comedogenic Scale Works

The comedogenic scale rates ingredients from 0 to 5 based on their likelihood of clogging pores. This scale was originally developed through rabbit ear assays in the 1970s and 1980s, where ingredients were applied to the inner ear of rabbits and observed for comedone formation. While the methodology has been criticised and refined over the decades, the scale remains a widely used reference point.

Why It Matters for Acne-Prone Skin

If you are prone to breakouts, understanding comedogenic ratings can help you make more informed product choices. Ingredients rated 3 and above are generally considered moderate to high risk, meaning they are more likely to contribute to clogged pores and acne.

However, comedogenic ratings are not the whole picture. The concentrationof an ingredient in a product matters significantly. An ingredient rated 3 may appear so far down the ingredient list that its actual concentration is negligible. Additionally, the overall formulation of a product can affect how individual ingredients interact with your skin. A well-formulated product with a comedogenic ingredient may not cause breakouts, while a poorly formulated product with “non-comedogenic” ingredients might.

Individual variation also plays a significant role. Everyone's skin is different, and an ingredient that causes breakouts for one person may be perfectly fine for another. Patch testing new products and introducing them one at a time remains the best approach for acne-prone individuals.

How to Use Comedogenic Ratings

Use comedogenic ratings as a starting point, not an absolute rule. If you have acne-prone or oily skin, consider being more cautious with ingredients rated 3 or higher, especially if they appear near the top of an ingredient list (indicating higher concentration). The DermLabs ingredient checker can help you quickly scan a product's full ingredient list and flag potential concerns.