A mechanical engineer got tired of seeing coconut oil recommended as a skincare miracle. It's healthy to eat. It's great for cooking. But if you're acne-prone, putting it on your face is a terrible idea — it scores 4 out of 5 for clogging pores in published research. And it's not alone.
So we built a tool. Paste your product's ingredients list, and we'll look up each one in our database of acne-causing scores from actual studies. No opinions, no marketing — just what the research says.
Comedogenicity is the tendency of an ingredient to clog pores and cause comedones (blackheads and whiteheads). It's rated on a 0–5 scale:
Most of these scores come from the rabbit ear assay, a lab test developed in the 1970s and widely used through the 1980s and 1990s. Ingredients are applied to the inner ear of a rabbit (which responds similarly to human pores), and researchers measure how much comedone formation occurs. It's not perfect, but it's the most systematic data we have for a large number of ingredients.
Our primary source is Fulton (1989), the most comprehensive comedogenicity study published. It tested hundreds of ingredients and cosmetic formulations using the rabbit ear assay. We also draw from Kligman & Mills (1972), Mills & Kligman (1982), Nguyen et al. (2007), and others.
Every ingredient in our database links back to a specific study. We mark each one as verified (directly from a published study), inferred (from related compounds), or unverified (widely cited online but we couldn't trace it to a paper). We're transparent about what we know and what we don't.
A high score doesn't mean an ingredient will definitely break you out. Everyone's skin is different. Concentration matters — an ingredient at 0.1% of a formula behaves differently than at 30%. And formulation matters — other ingredients can change how something interacts with your skin.
What we can tell you is what the research found when these ingredients were tested in isolation. If you're acne-prone and struggling to figure out what's causing breakouts, this is a good place to start looking.
Coconut oil, cocoa butter, olive oil, wheat germ oil — these all sound wholesome. They're popular in "natural" and "clean" skincare. But they all score high for clogging pores. Being natural, non-toxic, or good for your health has nothing to do with whether something will cause acne. These are separate questions, and this site is only about one of them.