There is a currently a lot written in skincare articles about mineral oils and how paraffin oil / Paraffinum Liquidum will form an occlusive layer on your skin and stop it “breathing” (See our May blog for more on whether skin actually breathes) You may also have read that mineral oil has large molecules that don’t penetrate the skin and sit on the skin surface, trapping sweat and bacteria beneath it.
A 2011 study compared mineral oil with jojoba oil, almond oil, avocado oil and soybean oil. The study found that none of the oils penetrated the skin further than the top 2-3 layers of corneocytes. Corneocytes are the upper layers of cells in the upper layer (stratum corneum) of the upper layer (epidermis) of the skin. So we are talking about an extremely thin layer and area of penetration! Only almond oil and soybean oil made it to the third layer, the other oils either sat on the skin’s surface or made it to the first two layers of cells.
In other words, plant oils act in the same way as mineral oil – forming a layer on top of the skin. The main difference mentioned by the authors of the study is that plant oils are similar in composition to skin lipids so they are taken up by the skin through enzymatic decomposition while mineral oil is not metabolised. Furthermore, many plant oils contain components such as triglycerides, flavonoids, phytosterols and tocopherols which provide additional benefits for your skin whereas mineral oil is very simple molecule made of only two atoms – carbon and hydrogen.
Oils applied to your skin trap help your skin to retain water and make your skin feel temporarily softer and smoother. They provide moisture to the top layers of the skin. There is no difference in this process regardless of whether you use mineral oil or plant oil. However the additional benefits of natural plant oils over mineral oils do mean that plant oils are a much better choice when it comes to looking after your skin.
Cecilia and Claire