Mineral oil, also known as paraffinum liquidum, has been used in cosmetics for over 100 years and is one of the most effective moisturisers known1. Recently, however, it’s come under fire in the battle that rages on between natural and synthetic skin care. Ardent proponents of the “natural” movement will tell you to avoid mineral oil at all costs. You might hear that it’s contaminated with carcinogens, that it causes acne, that it penetrates your skin and robs the skin of vitamins. Besides, natural alternatives are always better, right? Let’s take a closer look at the evidence against paraffinum liquidum.
Myth 1: Mineral oil contains carcinogens
This idea comes from the fact that some petroleum derivatives contain polycyclic aromatic compounds, shown to be carcinogenic in rats2. While mineral oil is certainly a petroleum derivative, the variation used in cosmetic and therapeutic products is refined to remove any such contaminants. In fact, mineral oil is the most highly purified form of petroleum1. There is absolutely no evidence that the grade of mineral oil in your favourite moisturiser is linked to any form of cancer.
Myth 2: Mineral oil causes acne
Many people will tell you that mineral oil is comedogenic (meaning it blocks pores) and therefore causes acne. This myth has been circulating in the cosmetic world for decades, to the point that it’s accepted as fact. But what does the evidence say? The first tests for comedogenicity developed in the 1970s used a rabbit’s ear test to evaluate comedogenic potential. Multiple studies found that on a 5-point scale of comedogenic potential, mineral oil scored between 0 and 2, and was categorised as “unlikely to be comedogenic in human skin.”3 You could argue that animal testing is never a perfect indicator of effects in humans (and you’d be right), so what happened when the experiment was done on humans? Basically, the outcome was the same. Paraffinum liquidum was found to be non-comedogenic in humans3. Of course, the best way to know whether a product is comedogenic is not to look at a single ingredient in the list, but the formulation as a whole. If you have oily, acne-prone skin, make sure the products you choose are labelled as non-comedogenic.
Myth 3: Mineral oil penetrates the skin
There is some evidence that hydrocarbons from mineral oil accumulate in the fat tissue of the body4. The authors of a 2011 study detected mineral oil saturated carbons (MOSH) in samples taken during elective cesarean section, and proposed cosmetics as a potential source. However, the data did not show a strong correlation between the use of cosmetics and MOSH accumulation. Other studies have shown that the amount of mineral hydrocarbons absorbed through the skin is negligible2,5. One of these studies conducted by the University of California looked at penetration of pig and mouse skin and found the hydrocarbons not only couldn’t penetrate normal, in-tact skin, but still failed to penetrate when the skin barrier was compromised5. The more likely source of MOSH in fat tissue is contaminated food, with mineral oil being detected in several other oils including olive oil6 and sunflower oil7. This is certainly a concern, but not a reason to avoid mineral oil in cosmetics.
Myth 4: Mineral oil robs the skin of vitamins
Many vitamins are oil soluble, so it’s been said that they will dissolve in mineral oil, and presumably be leeched out of the skin. Some sources even claim using this skincare containing the ingredient can leave you with a vitamin deficiency! While this is effective scaremongering, it is not backed up by a single shred of scientific evidence.
Mineral oil is inexpensive and a far more effective emollient than vegetable oils1, but as a product of petroleum it is a prime target for some ‘natural’ advocates. However, few cosmetic ingredients can boast such a long and safe history of use, and based on the evidence there is no reason to suspect that paraffinum liquidum in skin care is in any way harmful to your health.