A comedogenic ingredient or product is one that tends to clog pores, potentially leading to blackheads, whiteheads, or acne breakouts. Ingredients are rated on a scale from 0 (won’t clog pores) to 5 (highly likely to clog pores), and anything rated 2 or below is generally considered safe for acne-prone skin. But those ratings come with significant caveats that change how useful they actually are in practice.
How Pore Clogging Actually Works
Your skin constantly sheds dead cells inside each pore. Normally, those cells detach and get pushed out by the flow of oil your skin produces. A comedogenic substance disrupts this process in one of two ways: it either causes the lining of the pore to overproduce skin cells (a process called follicular hyperkeratinization), or it slows down the natural shedding of those cells. Either way, dead cells and oil build up inside the pore, forming a plug. That plug is a comedo, the technical name for a clogged pore, and it’s the starting point for most acne.
Different ingredients trigger this plug through different mechanisms. Some mimic your skin’s own oil too closely, mixing with sebum and thickening it. Others physically coat the pore opening. The end result is the same: a blocked follicle that can become a blackhead (open comedo) or a whitehead (closed comedo), and potentially an inflamed pimple if bacteria get involved.
The 0 to 5 Comedogenic Scale
Skincare ingredients are assigned a comedogenic rating from 0 to 5. A rating of 0 means the ingredient showed no tendency to clog pores in testing, while a 5 means it reliably caused clogged pores. In theory, sticking to ingredients rated 2 or below should reduce your risk of breakouts.
The problem is where those numbers came from. The original comedogenic ratings were generated using a test that applied concentrated ingredients to rabbit ears, which are far more sensitive than human skin. Even the researchers who developed this model later acknowledged it didn’t translate well to humans. A substance that irritated a rabbit ear frequently showed inconsistent results on human skin. With growing concerns about both accuracy and animal testing, the field has shifted toward human-based testing that evaluates finished products rather than isolated ingredients.
Common High-Risk Ingredients
Some ingredients consistently rank at 4 or 5 on the comedogenic scale. If you’re prone to clogged pores, these are the ones worth scanning ingredient lists for:
- Coconut oil (rated 5): one of the most commonly cited pore-clogging culprits, despite its popularity in natural skincare
- Cocoa butter (rated 4): rich and occlusive, frequently found in body lotions and lip products
- Isopropyl myristate (rated 5): a synthetic emollient used to help products absorb quickly
- Acetylated lanolin (rated 4): a modified form of the waxy substance from sheep’s wool
- Algae extract (rated 5): appears in many “natural” and anti-aging formulas
- Oleic acid (rated 5): a fatty acid naturally present in olive oil and many plant oils
- Flaxseed oil (rated 4): often marketed as a healthy, omega-rich oil for skin
- Lauric acid (rated 4): a fatty acid abundant in coconut oil
- Olive oil (rated 4–5): high in oleic acid, which makes it a poor choice for acne-prone facial skin
- Ethylhexyl palmitate (rated 4): a common emollient in foundations and sunscreens
Many “butter” ingredients also score at 4 or 5, including shea butter (listed as butyrospermum parkii, rated 3–5), avocado butter, aloe butter, and mango butter derivatives. The pattern is straightforward: thick, heavy, oil-rich substances tend to score higher.
Ingredients That Are Generally Safe
Several widely used skincare ingredients have low or zero comedogenic ratings. These include aloe vera, glycerin, hyaluronic acid, niacinamide, vitamin C, vitamin E, witch hazel, dimethicone (a silicone), and allantoin. Among oils, jojoba oil, safflower oil, and almond oil appear to carry a low risk of causing clogged pores.
Interestingly, some moisturizing combinations may actually help prevent clogged pores. Research on formulations combining lanolin with avocado oil, apricot kernel oil, and sunflower oil found they could protect the skin from dehydration, potentially reducing the excess sebum production that contributes to pore blockage in the first place. This highlights why finished products behave differently than individual ingredients in isolation.
Why Individual Ingredients Don’t Tell the Whole Story
One of the biggest problems with the comedogenic scale is that it rates isolated ingredients, not the products you actually put on your skin. A moisturizer might contain a small percentage of an ingredient rated 4, but that doesn’t mean the finished product will clog your pores. Concentration matters. So does the overall formulation: other ingredients in the product can change how a comedogenic substance interacts with your skin.
Researchers reviewing the current state of comedogenicity testing have emphasized that testing isolated ingredients rather than full product formulations is a methodological flaw that contributes to unreliable labeling. A 2025 review in JAAD Reviews called for standardized, human-based testing on final product formulations to determine true comedogenic potential. Until that becomes the norm, comedogenic ratings for individual ingredients remain a rough guide, not a definitive answer.
“Non-Comedogenic” on a Label Means Less Than You Think
The term “non-comedogenic” is not regulated by the FDA. There is no official definition, no required testing, and no approval process for using this claim. The FDA’s position on cosmetic labeling is that claims must be truthful and not misleading, but it does not maintain a list of approved or accepted claims for cosmetics. A brand can put “non-comedogenic” on any product without submitting test results to anyone.
This doesn’t mean every product making the claim is lying. Many reputable brands do formulate with low-comedogenic ingredients and test their products. But the label alone isn’t proof of anything. Treat it as a starting point, not a guarantee.
Your Skin Type Changes the Equation
Not everyone reacts to comedogenic ingredients the same way. Research has found that people with naturally prominent pore openings or existing comedones are far more likely to develop clogged pores from a given ingredient than people with smaller, tighter pores. In comedogenicity studies, researchers specifically recruit subjects who already have visible comedones or large pores, because those are the people most likely to show a reaction. If your skin doesn’t have those characteristics, a moderately comedogenic ingredient may never cause you a problem.
Ethnicity also plays a role. Studies comparing comedogenic responses across populations found that Asian subjects tended to have lower comedogenicity sensitivity than Caucasian subjects when exposed to the same test substances. This suggests that genetic differences in skin structure, sebum composition, or cell turnover rate influence how your pores respond to potentially clogging ingredients.
The practical takeaway: if you rarely get clogged pores, you probably don’t need to scrutinize every ingredient list. If you’re breakout-prone, especially along the jawline, forehead, or cheeks, checking for high-comedogenic ingredients is worth the effort.
Hair Products Are an Overlooked Source
Breakouts along the hairline and forehead often have nothing to do with your skincare routine. Shampoos, conditioners, styling gels, waxes, and pomades frequently contain oils that migrate onto your skin. The American Academy of Dermatology notes that oil-heavy styling products like pomades are a common culprit for forehead and hairline acne. Even shaving creams and aftershave can contain enough oil to trigger breakouts. If your acne concentrates around your hairline, temples, or the back of your neck, switching to oil-free hair products is a logical first step before overhauling your skincare.