• Violeta Camarasa, science journalist

    10 key questions regarding mineral oils

    Mineral oils have been used in cosmetics for the last hundred years. In recent decades they are among the components that most confuse consumers. The myths and misconceptions are many. How do mineral oils affect the health of the skin? Are they carcinogenic? Do they cause acne? Are they “natural”? Are vegetable oils safer?


    1. Which cosmetics contain mineral oils? We can answer this question more quickly by formulating the question in reverse, as these oils are the most common components in cosmetics. Paraffin oil, petroleum oil, liquid paraffin, white liquid petrolatum, white oil, petrolatum (vaseline), mineral oil, silicone quaternium, methylsilanol, microcrystalline wax – they go by many names. If any of these ingredients are featured on a label, it means that you are applying mineral oil to your skin.


    2. Why are mineral oils used so much in cosmetics? Mineral oils are colourless, odourless and inexpensive, they do not oxidize, remain in good condition and the irritant and toxicity risks are low. For these reasons, mineral oils are widely used in the cosmetics, pharmaceutical and food industries, among others. They work well in cosmetics as carriers or excipients for active agents, enabling these to function in ideal conditions.


    In dermatology they are considered safe and hygienic, given the low level of skin penetration; therefore, depending on the disorder and the type of skin, they may be more or less acceptable but are never prejudicial.


    3. What exactly are mineral oils? Mineral oils are complex mixtures of hydrocarbons obtained from the distillation of crude oil. Like the petroleum we use as fuel oil, mineral oils undergo a refining process to obtain highly purified materials. In fact, mineral oil is considered to be the purest and finest byproduct of petroleum.


    4. What are the benefits of mineral oils? Mineral oils themselves have no healing properties for the skin as they remain on the surface and cannot penetrate to the blood. Their effects are more physical than biological: they form a relatively impermeable barrier between the skin and air and act as an occlusive agent that retains moisture, protects and softens the skin and prevents irritation by the environment. These physical qualities have biological consequences in that the oil repairs damage, moisturizes, soothes and keeps skin healthy.


    Mineral oils are very effective in keeping the skin hydrated, which is why they are used so much in all kinds of products: creams, gels, eye shadows lipsticks, treatment masks, etc.


    5. What are the negative effects of mineral oils? Excessive use of mineral oils can, in the long run, lead to overhydrated skin. This may be counterproductive as the skin becomes accustomed to being oiled and a vicious cycle is launched in which the skin is no longer able to hydrate and protect itself. People with dry skin should try to avoid overusing products with a high concentration of mineral oils.


    Mineral oils are not recommended for people who perspire heavily because the oil’s occlusive capacity may hinder the release of sweat and cause dermatitis.


    6. Are mineral oils natural? The petroleum from which mineral oils are extracted is formed from plant and animal organisms buried millions of years ago. The chemical refining process means that they do not meet requirements for “natural” cosmetics; however, since they are inert materials the chemical process is very safe, which is why they are used in pharmaceuticals and food.


    Bear in mind that vegetable oils considered to be “natural” are also pre-treated to remove toxic substances. So, as always, remember that a product is not necessarily safer just because it is natural.


    7. Are mineral oils comedogenic? One of the adverse effects commonly attributed to mineral oils is that they are comedogenic; in other words, because they are occlusive, they may block the skin’s pores and facilitate the development of comedones and pimples. In 2005, a major study published in the prestigious Journal of Cosmetic Dermatology concluded that mineral oils are not comedogenic. If your skin is prone to acne you should choose products labelled “non-comedogenic”. A label indicating that a product is “without mineral oils” is no guarantee of anything.


    8. Are mineral oils carcinogenic? Another myth attributed to mineral oils is that they contain carcinogens. While it is true that certain petroleum byproducts – like some of the polycyclic aromatic compounds – may contain carcinogens, the byproducts used in cosmetics are highly refined and free of such compounds.


    Their purity is regulated by various international organizations. Also, no dermatological or medical studies exist that warn of a link between mineral oils and any kind of cancer.


    9. How do mineral oils differ from vegetable oils? According to an important study published in 2012, the differences between vegetable and mineral oils are minor, mainly related to their occlusive capacity.


    Mineral oils are more effective in moisturizing and protecting the skin, whereas vegetable oils are biologically more effective for other uses, such as skin whitening or itch relief. Thus, vegetable or mineral oils are more or less useful depending on the effect sought and the skin’s characteristics.


    10. Should mineral oils be avoided? Unless you have dry skin problems or other complications for which your dermatologist has issued specific instructions, avoid products with high concentrations of mineral oil. At low doses, they simply help active agents function better and contribute to hydrating the skin. Remember that it is best to only use the cosmetics that your skin needs to be healthy, no more and no less.