Some of you may not know that, although I do not practice, my education was as a physiologist and the science habits I learned have lingered. I can’t hear people make certain types of claims without wanting to know the source of their science and wanting to know their definitions.
I continue to hear and read various claims about cosmetic products applied to the skin (I’ll address lipstick later):
– “80% of everything you put on your skin is absorbed!”
– “60% of everything you put on your skin is absorbed!”
– “98.8% of “chemical such and such” is absorbed into your skin.”
– “Your skin “eats” the products you put on it.”
These types of comments have always bothered me – why? My weird brain:
1 – Personal care formulas are made of a range of all water-base, all oil and everything in-between. If someone said that 60% of a formula absorbs into skin and it is 60% water and the rest is derived from oil, do they mean that 60% of the water soaked in? Or do they mean that some of the water and some of the other ingredients “absorb”? What do they mean?
2 – Think about it – if your skin absorbed 60 to 80% of what you put on it, wouldn’t you start to look a little puffy? I keep having visions of the Michelin Man when we get out of the shower . . . if we absorb all this stuff – where does it go? What happens in the shower, do we absorb all that water? Where is the logic in these statements?
3 – I know, because I have done my homework, that most oils are large molecules. They just are too big to be absorbed into skin – they sort of snuggle down into the 2nd layer of the epidermis and stay there, or they sit on top of the skin. There are some small molecules, and I would question those, but I doubt it is 60 or 80% of any formula.
I believe we should always question any blanket statement. They sound too much like myth. When you think about the fact that most liquids have some degree of volatility, then we need to account for temperature, humidity, and the individual volatility of the material. Alcohol, as we can all feel, evaporates rather quickly. If skin or the air is warm, alcohol volatilizes really fast. So, if essential oils are in the formula, do they evaporate? If it is cold, do they all congeal on top of your skin? What about formulas high in water? I’m going to guess they would behave differently in Arizona in July versus Maine in December.
The physical science of liquids (lotions and other products) applied to skin is extremely complex and NEVER predictable enough to say that any specific percent of any topical application is consistently “absorbed”. (I actually read a couple of heavy-duty research papers that demonstrate this statement through research). Next time you hear such a statement, ask what the heck they mean. Absorbed to where? Absorbed under what conditions? Which parts of the formulas – the water, the oil, some magic combination?
That said, I do suspect (have read verification) that the vast majority of personal care items are washed down our drains. That does worry me. More on that later.
Oh, and if you want to learn a bit more, check out this web site to learn about skin structure: http://dermatology.about.com/cs/skinanatomy/a/anatomy.htm
Happy Saturday! Gay