For the past five years or so I have read about supposedly false advertising claims challenges by litigators regarding the claim “oil free.” I would like to express my opinion on this matter and hopefully clarify some things. It is apparent from the few listed references^1,2,3 and the references within them, that there are those that consider the following chemical functional groups as “oil”:

• Hydrocarbons (alkanes, alkenes)—“such as squalene, commonly sold as squalane oil”
• Triglycerides—“such as glycerol tristearate, also known as stearin”
• Esters—such as ester oil
• Fatty acids—such as palmitic acid
• Certain silicones—such as alkyl dimethicone and
• Fatty alcohols—sterols

Under these chemical functional groups, the following cosmetic ingredients would be considered “oils”: 

• Squalene
• Glycerol or Glycerol Tristearate
• Fatty acids such as Stearic Acid and Palmitic acid
• Dimethicone – any of the D4-6
• Isododecane
• Tridecyl Trimellitate
• Octocrylene
• Caprylic/Capric Triglyceride
• Ethylhexyl Stearate
• Tocopherol Acetate
• Jojoba Esters

This is not an exhaustive list, but pertains to the chemical functional groups identified. In short, any substances that are at least partly fat-soluble or looks, feels and interacts with water the way olive oil would is considered an “oil”.^1,2,3 Therefore, any substance that behaves like oil may be considered as “oil”.² Really!? This thinking ignores science and distorts common sense. As I will show, because a chemical has a certain property or properties with oil, it does not make it an oil.

Oils  or Something Different?

Historically, in the conventional sense, “oil” denoted olive oil and later other plant derived oils such as coconut oil, corn oil, etc. As usually happens, when new materials come to light, they are usually described based on what is familiar—based on a familiar attribute. For example, certain processing of soy and almonds give a milk-like material that gave rise to the consumer terms “soy milk” and “almond milk”. As such, certain material that were oil-like, had “oil” attached to them such as essential oil (although comprised of chemical compounds from plants it is a technical name) and silicon oil (completely synthetic). That is the nature of language. 

Olive oil and the like moisturize skin. These ingredients have many good formulation attributes. However, they tend to leave skin “oily” leading to a patchy or smeared appearance—a negative aesthetic characteristic. They tend to be comedogenic, (clog pores and causes acne) especially among individuals with oily skin. As such, some consumers preferred products that avoid the negative aspects of oils. The beauty and skincare industry always being at the forefront of innovation and customization, offers products tailored to every skin type and concern. To accommodate some consumers therefore – those with oily skin and otherwise prone to comedones and acne, the industry started formulating products free of oil. 

Simply, when a cosmetic or skincare product is labeled “oil-free,” it signifies that the formulation does not contain added oils as ingredients; instead, it relies on other ingredients, like silicones or water-based alternatives, to provide hydration, texture and effectiveness without contributing to the oil content. Consumers began associating the claim with purity, lightness, and non-greasy textures. By the 1980s, products labeled as oil-free gained a reputation for being universally appealing, even to those without oily or acne-prone skin, as they addressed a broader preference for lightweight cosmetics. 

To communicate that to their customers, brands label their products as “oil-free.” It was historically understood, and should be understood today by the cosmetic consumer, as denoting free of naturally derived oils but more importantly, as simply being non-greasy and non-comedogenic. I emphasized non-comedogenic because that is an important implication of making an “oil-free” claim.

For many years cosmetic manufacturers have marketed certain cosmetic products that do not contain naturally derived oils, like olive oil, as “oil free.” However, oils are a large and diverse family of naturally derived chemicals, with different names and with a variety of effects on the skin that contain the word “oil” in their names (e.g., Abies Alba Leaf Oil, Castor Oil Benzoate, etc.). There are about 4,590 registered ingredients with “oil” in their name in the on-line International Cosmetic Ingredient Dictionary & Handbook or INCI, a registered trademark of the Personal Care Products Council (PCPC). All are naturally derived. Neither essential oil nor silicon oil are on this list. As such, marketers claiming “oil free” avoided such ingredients. In other words, if the ingredients on a product’s label do not have “oil” in their name, the product is considered “oil free.” But this claim implies the product is non-comedogenic; it must also deliver on that.

As previously noted, as it is apparent from the given references, that some consider that if a chemical has “oil” like characteristics, the ingredient should be considered as being an “oil” regardless of its biological and most physicochemical properties are not that of oil. As I will discuss below, PCPC, cosmetic formulators and consumers, don’t define oils the same way. That is, that an oil is any substance that is immiscible in water. Based on such an argument—a non-chemical argument—the 4,590 registered INCIs with “oil” in their name would be but a drop in a bucket. The immiscible in water criterion encompasses a wide variety of materials and ingredients with very different functions and qualities. 

Immiscible in water does not an oil make

Bottom line, in cosmetic labeling, the term “oil free,” refers to olive oil and the like that may be comedogenic. Not to imply that all “oil” ingredients are bad or comedogenic. Natural oils like, for example, argan oil or jojoba oil have been celebrated for their skin-repairing properties and may be suitable even for some individuals with oily skin. Their inclusion in a formula does not necessarily make the product comedogenic. Cosmetic products, including those labeled “oil free,” may contain other ingredients that may be synthetic, such as dimethicone or chemically derived from oils, such as fatty acids (e.g., stearic acid), that may have some physicochemical properties as “oil” but are not “oil” and therefore do not have the same effect on human skin.  

Alternative ingredients may or may not clog pores in the same way traditional oils do. Based on challenges, it is argued, as an example, that dimethicone and stearic acid are oils because they are immiscible in water. That is not so. To demonstrate the point, the following argument is a distinction between true oils, stearic acid and dimethicone. Chemicals are immiscible with water due primarily to their hydrophobic character. As such, all true oils are “hydrophobic,” but not all hydrophobic chemicals are considered oils. As per FDA and PCPC indications, true oils are natural hydrocarbons that are liquid at room temperature. They may be derived from animal, plants or petrochemicals that are “fossilized” biological matter. Or, derived from renewable sources such as corn, palm fruit, sugar cane, etc. PCPC, responsible for creating ingredient names for cosmetic labeling purposes (i.e., INCI), defines fats and oils as follows: glyceryl esters of fatty acids (triglycerides) normally found in plant and animal tissues, including those that have been hydrogenated to reduce or eliminate unsaturation. Also included, are synthetically prepared esters of glycerin and fatty acids. They possess the structure as shown by Figure 1. What distinguishes an oil from fat is the state they are in at room temperature. Oils are liquid while fats are solid. Fats and oils, being esters, can be hydrolyzed to yield glycerin and mixtures of fatty acids (Figure 1). Stearic Acid is a fatty acid that conforms generally to the formula shown by Figure 2. Stearic acid is part of an oil, just as an arm or a leg is part of a person. Or, as an electron is part of an atom. They are components of a whole. An appendage does not make a person, an electron does not make an atom, and stearic acid does not make a triglyceride. Chemically speaking, stearic acid is not oil. As the name indicates, it is an acid—“oil” is not viewed as such. Intrinsically therefore, stearic acid has different physicochemical characteristics. 

Most notably, because it is an acid, it has some water solubility (0.3 mg/100 g of water at 20°C) which makes the immiscible argument untrue. Stearic acid (fatty acids in general) may be obtained from oil by hydrolysis of common fats and oils—i.e., by destroying oil to produce something not oil. Because stearic acid is less dense than water, it does not make it an oil. Cork is less dense than water. Oils are less dense than water but not all chemicals less dense than water are oils. The immiscible and less dense than water argument therefore does not hold. Just because a chemical has those two properties in common with oil it does not make it an oil. Many chemicals with these properties are not oils. One should not “cherry pick” and ignore the multitude other properties not in common with oil. For illustration purposes, some differences are shown in Figure 3. In fact, stearic acid is used for the dispersion of pigments in oil phase. There is no need to do that if stearic acid is equated to oil. This further proves that stearic acid has different physicochemical properties than oil and is therefore not oil. As Figure 3 shows, the situation is even more preposterous when one equates dimethicone to oil. Dimethicone is neither a hydrocarbon nor natural; it is a synthetic silicone polymer. Dimethicone is a mixture of fully methylated linear siloxane polymers blocked with trimethylsiloxy units – i.e., synthetic. It conforms generally to the formula as shown by Figure 4.

Dimethicone’s overall physicochemical characteristics and skin kinetics/behavior are different from “oil.”  Equating dimethicone to oil is analogous to equating a person to a robot. You know what I mean. One is hydrocarbon based, and the other silicon based.  

Oil-free expectations

Bottom line, these three chemical species are as distinct as  an elephant, lion and crocodile. Yes, they have some similarities like four legs and two eyes, but the differences are what distinguishes them and makes them unique – look different, behave different, live in different environments, eat different things, present different potential threats.

The “oil-free” claim on cosmetics is a marketing term that signifies a thoughtful approach to tailored skincare and makeup addressing the concerns of individuals with oily, acne-prone or sensitive skin. Demand for oil-free products continues, driven by consumers who prioritize skin health and seek solutions that align with their individual skin types and aesthetics. Creating oil-free products that deliver the same richness, hydration and performance as their oil-based counterparts presents unique challenges for cosmetic chemists. Oil-free formulations rely on alternative ingredients like synthetic emulsifiers, which must be carefully balanced to avoid compromising the product’s effectiveness or stability. 

When a product claims to be “oil free,” all one should expect is that its formula does not contain any ingredient with the word “oil” in its name and that it is non-comedogenic. FDA expects less for the same claim for food. Such a product must not contain any added fats or oils, except for trivial or negligible amount of fat. The product must contain less than 0.5 grams of total fat per serving and must be clearly indicated on the label (www.ecfr.gov; www.fda.gov).

Acknowledgments 

The author expresses his gratitude to Hideo Hata, senior vice president, Blue Sky Innovation & Product Integrity at Shiseido for his input with chemistry and his overall review.

References

1. Grabenhofer, R. January 26, 2021. J&J, Walgreens-Boots, L’Oreal, Maybelline and E.L.F. Named in ‘Oil-free’ False Advert Suits. Cosmetics & Toiletries (https://www.cosmeticsandtoiletries.com/regulations/claims-labeling/news/21844011/jj-walgreens-boots-loreal-maybelline-and-elf-named-in-oil-free-false-advert-suits).
2. Rizzi, C. July 1, 2021. ‘Oil-Free’ Clinique Skincare Products Contain Oil, Class Action Says. ClassAction.org (https://www.classaction.org/news/oil-free-clinique-skincare-products-contain-oil-class-action-says).
3. Cosmetics & Toiletries. Novembre 16, 2021. Clinique Labs Can’t Slip Past ‘Oil-free’ False Advert Suit (https://www.cosmeticsandtoiletries.com/regulations/claims-labeling/news/21903193/clinique-labs-cant-slip-past-oilfree-false-advert-suit).

About the Author

Lambros Kromidas, MS, PhD, is VP-global legal regulatory affairs liaison at Shiseido. Prior, he held management positions at Avon, Coty, Beiersdorf and RIFM. He received his MS in microbiology and PhD in toxicology from St. John’s University, New York, NY, and conducted post-doctorate research at Cornell University Medical College, Department of Physiology, New York, NY. He is a member of SCC, SOT, and an active PCPC participant and occasional Happi contributor.

Conflict of Interest Statement 

The viewpoints expressed in this paper are solely those of the author and do not necessarily reflect those of any competent authority or company. The purpose of this article is to guide and inform the reader. The reader is encouraged to verify any opinions and facts the author presents.