Monday, November 8, 2010
Much maligned ingredients: Mineral oil (part 1)
So what exactly is mineral oil? Its INCI is Paraffinium liquidum, and it is derived from petroleum. It's a linear hydrocarbon oil with an unlimited shelf life and an HLB value of 10.5. It's an occlusive and emollient ingredient that repels water, and it's used to increase the moisturization of our skin. It is a water white, odourless, colourless, oil soluble ingredient that defoams our surfactants and can feel quite greasy on our skin. It's safe to use at up to 82% in our oil containing or anhydrous creations, but ideally you'd use it at 5% to 70% because it does feel so greasy.
It's used a lot in commercial products for two reasons - it's inexpensive and it's consistent. I have no idea what the market price for mineral oil might be, but I know I can get it from my local supplier for about half the cost of any other oil. Cost is important, but it's the consistency that's important to cosmetic chemists. Vegetable oils or botanical ingredients change from batch to batch. (You'll know this when you see different shades of butters or oil or extracts and find they behave differently in your products.) Mineral oil is the same every single time, which makes it much easier to guarantee the viscosity, skin feel, and interaction of the ingredients in your formula.
A quick note - There are a number of grades of mineral oil. The two most common are industrial grade and cosmetic grade. These are vastly different creatures, and any studies done on industrial grade mineral oil are not valid when it comes to cosmetic grade mineral oil. Watch for this when you're doing your research because a lot of the studies are on long term exposure to a lot of industrial grade mineral oil as opposed to long term exposure to a titch of cosmetic mineral oil.
So now that you know a little bit about what it is and what it offers, let's take a look at why people hate it so much tomorrow.