Mineral oil is a highly refined and purified synthetic oil that is created as a byproduct of refining petroleum. It is used in multiple products, including foods, skin care products, and medications.1–3
Mineral Oil Safety
Scientists generally consider mineral oil to be safe for humans to use in both topical (applied to the skin) and oral forms. There is some concern about long-term use of oral mineral oil, as some studies in animals have shown signs of mineral oil toxicity after 90 days of oral use. However, the evidence indicates that topical use of mineral oil is quite safe, and there is no evidence of any danger in exposure to topical mineral oil.4
Mineral Oil in Cosmetics
Mineral oil has been used in cosmetic products for more than 100 years. The best-known cosmetic product containing mineral oil is baby oil. Baby oil is mineral oil with fragrance added, and people use it to moisturize and soften skin, soothe skin inflammation, help treat mild eczema (an inflammatory skin disease), and clean inside the ears.
Mineral oil comes from petroleum, which is a natural oil. However, because of the chemical processing involved in creating mineral oil, it does not qualify as a “natural” oil in skin care products.3
Mineral Oil and the Skin
Mineral Oil vs. Vegetable Oils
Topical skin care products, cosmetics, and medications often contain some sort of oil, either a vegetable oil--such as safflower oil--or a petroleum-based product like mineral oil. All oils act as a skin moisturizer, but vegetable oils do this differently than mineral oil:
- Vegetable oils penetrate the deeper layers of skin and interact with molecules in the skin to increase moisture.
- Mineral oil does not penetrate beyond the outermost layer of the skin and is inert, meaning that it does not interact with skin molecules. Instead, it moisturizes by “sitting on top" of the skin and providing a barrier that keeps moisture inside the skin.3,5
In addition to moisturizing skin, vegetable oils provide other benefits that can help heal the skin, whereas mineral oil lacks these properties:
- Vegetable oils contain antioxidants (molecules that prevent cell damage from harmful molecules called oxidants), while mineral oil does not. Some vegetable oils also have antibacterial and anti-inflammatory properties. Lastly, because vegetable oils penetrate into the skin, they can help deliver topical medications into the skin.3,5
Mineral oil does not contain antioxidants, does not have antibacterial or anti-inflammatory properties, and sits on top of the skin, which means it cannot help deliver topical medications.
Skin Penetration and Delivery of Medications
It is important for topical medications to be able to penetrate the skin to deliver the medication to where it is needed. Vegetable oils can help with this penetration, whereas mineral oil cannot:
- Vegetable oils penetrate into the skin, and are thus often added to topical medications to aid with the penetration of the medication into the skin.
Mineral oil does not penetrate into the skin, and several studies have confirmed that it is not effective at delivering medications into the skin.3,6,7
Reducing Side Effects of Medications
However, mineral oil may help to reduce the negative side effects of medications that cause skin irritation.
A 2007 study in the International Journal of Cosmetic Science found that adding mineral oil to a lactic acid treatment reduced the stinging and burning caused by the lactic acid. The authors concluded:
“Increasing the mineral oil content…from 10% to 50% tended to decrease the stinging potential of the [lactic acid] formulation.”8
Skin Barrier Function
The term skin barrier function refers to the protective barrier of the outermost layer of skin. This outermost layer of skin prevents water from evaporating and drying out the skin. The skin barrier also protects skin against the environment. When skin barrier function is impaired--as it is in acne and some other skin diseases--too much water evaporates from the skin, causing irritation. Because mineral oil sits on top of the skin, it creates an artificial barrier that traps moisture inside. This may help improve skin barrier function, at least in the short term, which could, hypothetically, be beneficial for acne. Whether mineral oil improves skin barrier function is a matter of debate among scientists: some studies indicate that it does not improve skin barrier function, while many other studies indicate that it does.3,9
Comedogenicity (Potential to Clog Pores) of Mineral Oil
When using any oil on acne-prone skin, we need to consider whether it is comedogenic (tends to clog pores). Some oils are comedogenic, and other oils are not. Mineral oil is non-comedogenic, so it is safe to use on acne-prone skin.3
Mineral Oil in the Treatment of Acne and Other Skin Conditions
There is no research concerning the use of mineral oil in treating acne. There are a few studies that suggest that it may help in treating skin dryness and irritation in other skin conditions, though these studies also indicate that mineral oil is not as effective as other treatments for dry and irritated skin.10–12
Mineral Oil for Atopic Dermatitis
People with atopic dermatitis, which is a very common skin condition that shows itself as a red, itchy rash on the skin, have impaired skin barrier function that leads to irritation and inflammation of the skin. This is potentially interesting when it comes to acne, since people with acne also tend to have an impaired barrier function.
In one 2014 study, mineral oil reduced symptoms of atopic dermatitis, but only to a moderate degree. Would it also do the same for acne? Since atopic dermatitis and acne are different skin conditions, and mineral oil only worked to a small degree on atopic dermatitis, until we get direct research on mineral oil and acne, we should not assume mineral oil will reduce acne symptoms.
One 2014 study in the International Journal of Dermatology compared mineral oil and virgin coconut oil in treating atopic dermatitis symptoms. This study found that mineral oil reduced symptoms by 38% and coconut oil reduced symptoms by 68%. In other words, the mineral oil helped, but it was not as effective as the coconut oil.10However, when extending these results to potential acne treatments, it is important to know that coconut oil is highly comedogenic and may not be a good choice for acne-prone skin.
Mineral Oil for Skin Irritation
Any type of repeated physical irritation to the skin can lead to acne. The two studies we have on mineral oil and skin irritation show us that it might help reduce irritation either to a small degree or not at all.
The first study, published in 2007 in Skin Research and Technology looked into how tissues coated in various substances might help reduce the irritation that comes from repeated use of tissues in people with allergies or the common cold. One of the lotions in the study contained mineral oil and showed that it helped, but only to a small degree:
This study found that the tissues containing mineral oil did help reduce irritation, but they did not help as much as the tissues containing other ingredients.11
The second study, performed on pigs and published in 2015 in the International Journal of Cosmetic Science, looked at whether adding mineral oil or vegetable oils to cleansing products could reduce irritation in the skin of the pigs after cleansing, and showed disappointing results for mineral oil:
This study found that mineral oil did not help at all, whereas sunflower seed oil did.12
The Bottom Line
While mineral oil does not appear to hold a lot of promise in treating skin conditions, including acne, it has been used for over 100 years and the evidence shows us that it appears to be a safe and inert oil that will not clog pores and should help keep the skin moisturized.