Comedogenicity is generally defined as the ability of an ingredient to clog pores and cause comedones (acne papules and their most common forms as white and black heads). So the logic goes - the more comedogenic ingredients in a skincare product, the higher the chance to break out, especially if you are prone to acne or you have oily skin. Unfortunately (or fortunately), it’s not quite that simple…
Comedogenic rating is a very debatable topic, because it is not a classification based on a specific index, rather on how many sebaceous follicles become microcomedones and comedones per square centimeter following a repeated application of a certain substance.
If you look up online 'comedogenic ratings', you will find so many different charts at times contradictory; in our opinion, they often do not provide the best advice on how to correctly identify and avoid highly comedogenic ingredients in a skincare product.
Over the years, when formulating and testing skincare products, we have collected quite a lot of data on comedogenicity based on a variety of oils, suppliers and organized by skin type and condition. This helped us a lot in improving our formulas, especially for facial oils; we want to share our findings hoping to help you identify how to avoid breakouts by using the wrong skincare ingredients.
In this article you will learn:
- The difference between acneic and comedogenic ingredients
- Why concentration and combination of comedogenic ingredients is so important
- Fatty acids and their role in skincare and comedogenicity or how much they clog pores
- Comedogenic ratings definition
- A comprehensive list of natural skincare ingredients (wholesome and naturally derived) and their tentative comedogenic classification
- How to evaluate face and body oils comedogenicity
WHY COMEDIGENICITY RATINGS ARE APPROXIMATE
In trying to identify fixed comedogenicity ratings of a specific fatty acid, there are 4 main issues:
- Comedogenic tests have been carried out mainly on rabbits and inside the human hear; therefore; results may differ quite a lot from exposed human skin;
- Not only there is very limited research on comedogenicity available, but also only a few fatty oils have been tested, a fraction of what is currently used in skincare;
- When testing natural fatty oils, the concentration of fatty acids of the same type of oil or butter, varies depending on the source and harvest, impacting the final evaluation of comedogenicity;
- Some oils / butters are also available as 'refined' (extra processed) therefore less comedogenic; when listing ingredients using the INCI system, there is no differentiation between virgin or refined.
Therefore, any Comedogenicity Ratings is approximate. Let's try to understand more on how we identify a range of comedogenicity.
WHAT IS THE DIFFERENCE BETWEEN ACNE AND COMEDONES?
Acne is a skin condition that happens when sebaceous glands are infected. When you experience acne, the skin develops red bumps as the result of an over-production of sebum, and/or changes in hormones.
A Comedo is a very dilated pore (the 'hole' surrounding a hair follicle - with or without hair) filled with dead skin cells, dirt, and sebum. If a comedo is open, the pore will look like a blackhead; if it is closed (so the skin covers it), it can cause inflammation, pimples, and whiteheads. It is the first step towards acne.
An Acnegenic ingredient can cause a general worsening of pre-existing acne. Some examples: Alcohol, mineral oils, Lanolin, Sodium Lauryl Sulfate, many essential oils...
A Comedogenic ingredient acts like glue on the surface of the skin: dead skin cells will stick together more and more, causing blackheads and whiteheads, not acne. Some examples: Coconut oil, Neem oil, Cocoa butter, Shea butter...
Applying too often and too much occlusive oils and butters can increase the formation of comedones.
IS THERE ANY 100% RELIABLE CLINICAL TEST TO RATE COMEDOGENIC INGREDIENTS?
Several tests were made applying different comedogenic ingredients on rabbit ears. Because rabbit ears are more sensitive than human skin, they reacted to comedogenic ingredients faster, and the results were not 100% applicable to human skin. Therefore, all ratings are not backed by complete clinical trials on human skin (this would be a mammoth task!) and the effects may vary from person to person.
One of the most reliable studies was done by Dr. Fulton's 1989, professor of Chemistry at UCLA: "Comedogenicity and irritancy of commonly used ingredients in skincare products" but many natural key cold pressed plant oils like Argan, Rosehip, Avocado... were not tested.
CONCENTRATION AND COMBINATION OF COMEDOGENIC INGREDIENTS CAN CHANGE EVERYTHING
Key fact 1) even if an ingredient is comedogenic on its own, if blended in with the correct low concentration (less than 5%) in a product, it might not make that product comedogenic overall.
Key fact 2) even if a product is formulated without any known comedogenic ingredients, it can still be mildly comedogenic on the skin for many.
Key fact 3) when non-comedogenic skincare ingredients are blended together, the combination could sometimes be more comedogenic than the single ingredients themselves.
Key fact 4) How a skincare ingredient is dissolved in a formulation can also change the overall comedogenic rate of the final product.
Key fact 5) the thickness of a plant oil does not always equal to very high comedogenicity (Castor oil, for example, is very thick yet minimally comedogenic)
Low to moderately comedogenic oils yet important for their vitamins and minerals (Caprylic/capric triglyceride or fractioned Coconut oil, Avocado oil, Isoamyl laurate, Apricot oil, Chia seed oil)
Very slightly comedogenic Squalane, Raspberry oil, Tamanu oil.
Fairly high comedogenic Moringa oil (very small percentage)
ARE ONLY COLD PRESSED OILS, NATURAL BUTTERS AND WAXES COMEDOGENIC?
Definitely not. The list of synthetic cosmetic ingredients with high comedogenicity is very long! Some examples: Isopropyl palmitate, Decyl oleate, Capric acid, Octyldodecanol, Mineral oils...
FATTY ACIDS WITH LOW AND HIGH COMOGENICITY PROPERTIES
Fatty acids are the main constituents of cold-pressed oils. As a general and easy to remember rule, look at 2 key Fatty acids costituents:
Oleic acid is more occlusive and tends to clog pores. Oils rich is Oleic acid are heavier, richer, and suitable for dry skin. (Olive oil, Camellia oil, Sweet Almond oil, Avocado oil, Hazelnut oil...)
Linoleic acid is way lighter, absorbs fast, and does not clog pores. Oils rich in Linoleic acid are thinner, and they work very well with oily and acneic skin. (Borage oil, Evening Primrose oil, Grapeseed oil, Pumpkin oil...)
ONE EXCEPTION - RINSE OFF CLEANSING BALMS
Cleansing balms formulated with mild surfactants and occlusive butters fit in the 'no-no' category of comedogenic skincare. However, because they are combined with a surfactant and they are rinsed off, they do not clog pores and actually are a good alternative to harsh cleansing products that tend to leave the skin very dry and strip off too much sebum.
GENERAL COMEDOGENIC RATING FOR COLD PRESSED OILS
Ingredients are generally ranked as follows:
- 0 – NON-COMEDOGENIC (do not clog pores)
- 1 – SLIGHTLY COMEDOGENIC (very low chance of clogging pores)
- 2 – MODERATELY LOW COMEDOGENIC (may clog pores for some but be fine for most)
- 3 – MODERATELY COMEDOGENIC (will clog acne prone/oily skin type)
- 4 – FAIRLY HIGH COMEDOGENIC (will clog pores for almost all skin types)
- 5 – HIGHLY COMEDOGENIC (will clog pores)
IMPORTANT - The ratings below represents a range, not definitive rules. All oils / butters have been classified in their virgin state and using samples from a variety of suppliers.
NON TO SLIGHTLY COMEDOGENIC OILS/BUTTERS
LOW TO MODERATELY COMEDOGENIC OILS / BUTTERS
FAIRLY HIGH COMEDOGENIC OILS / BUTTERS
SKIN TYPES: OILY, BLEMISHED, COMBINATION, NORMAL
SKIN TYPES: NORMAL, DRY, MATURE, DULL
SKIN TYPES: VERY DRY SKIN *** USE IN LOW CONCENTRATION
|Abyssinian Seed Oil||1||Acai Berry Oil||2||Bacuri Butter||4|
|Black Currant Seed Oil||1||Almond Oil, Sweet||2||Cocoa Butter||4|
|Blackberry Seed Oil||1||Andiroba Seed Oil||2||Coconut Butter||4|
|Blueberry Seed Oil||1||Apricot Kernel Oil||2-3||Coconut Oil||4|
|Borage Oil||1||Argan Oil||2||Cupuacu butter||4|
|Broccoli Seed Oil||1||Avocado Oil||3||Flax Seed Oil (Linseed)||4|
|Castor Oil||0-1||Babassu Oil||2||Palm Oil||4|
|Cloudberry Seed Oil||1||Baobob Seed Oil||2||Soybean Oil||4-5|
|Cucumber Seed Oil||1||Black Cumin Seed Oil||2||Wheat Germ Oil||5|
|Elderberry Seed Oil||1-2||Brazil Nut Oil||2|
|Goji Berry Seed Oil||0-1||Buriti Oil||2-3|
|Grapeseed Oil||1||Cacay oil||2|
|Guava Seed Oil||1-2||Camellia Seed Oil||3|
|Hazelnut Oil||1||Carrot Seed Oil||3-4|
|Hemp Seed Oil||1||Cherry Kernel Oil||2|
|Isoamyl laurate||1-2||Chia Seed Oil||2|
|Kiwi Seed Oil||1||Coconut Oil, Fractionated||2-3|
|Meadowfoam Seed Oil||1||Cottonseed Oil||3|
|Oat Oil||1-2||Cranberry Seed Oil||2|
|Passionfruit (Maracuja) Seed Oil||1-2||Evening Primrose Oil||2-3|
|Perilla Oil||1-2||Jojoba Oil||2|
|Plum Kernel Oil||1-2||Kukui Nut Oil||2|
|Pomegranate Seed Oil||1||Macadamia Nut Oil||2-3|
|Poppyseed Oil||1||Mango Butter||2-3|
|Prickly Pear Seed Oil||1-2||Mango Seed Oil||2|
|Raspberry Seed Oil||1-2||Marula Oil||3-4|
|Red Raspberry Seed Oil||1||Moringa Oil||3-4|
|Rosehip Seed Oil||1||Murumuru Butter||2-3|
|Sacha Inci||0-1||Neem Oil||3-4|
|Safflower Oil (High Linoleic)||0||Olive Oil||3-4|
|Sea Buckthorn Oil||1||Papaya Seed Oil||2-3|
|Shea Butter||0-2||Peach Kernel Oil||2|
|Strawberry Seed Oil||1||Pequi Oil||3|
|Sunflower Seed Oil||1-2||Pumpkin Seed Oil||2|
|Watermelon Seed Oil||1||Rice Bran Oil||2|
|Sesame Seed Oil||3|
|Tomato Seed Oil||2|
|Walnut Seed Oil||2|
- Oils can be classified 0 to 5 in terms of how much they facilitate the formation of comedones, 0 being no comedogenic and 5 extremely occlusive.
- To determine how high an oil is comedogenic, look at the total concentration of Oleic acid; the highest Oleic acid % means higher comedogenic value
- Very high comedogenic oils, if used in very low concentrations when blended with other ingredients, (less than 5%) have little or negligible comedogenic effect.
- Cleansing balms (rinse off) formulated with a surfactant and comedogenic butters, are actually not very comedogenic.