In the last post we learnt about the GREASE-FALL, which is “how to distribute the fats in order to obtain a good specific kind of cream”.
In this post we are going to go a step forward: we will learn about the fatty acids inside the natural fats (oil or butter). This will help you to formulate, specially if you suffer of acne.
[This is just a picture of an eye cream I made (it is a caffeine and blueberry eye cream with 7% fats... I think I am going to post the recipe in the near future :) ) because I was thinking that maybe you don't really believe YOU CAN ACTUALLY MAKE CREAMS! :) So here is the proof :) I did it, so you can do it too.Just keep learning and soon enough you will realize that there is nothing better than your own creams! :D ]
Now, back to our fatty acids :D
There are many fatty acids in oils (and butters).
I am going to talk about the most common ones.
They are divided in three bigger groups:
1) Saturated fatty acids:
– palmitic acid
– stearic acid
– lauric acid
2) Monounsaturated fatty acids:
– palmitoleic acid
– oleic acid
3) Poliunsaturated fatty acids:
– linoleic acid (more famous as Omega-6)
– alpha-linoleic acid (more famous as Omega-3)
Saturated fatty acids are found mostly in butters (the high presence of saturated fatty acids, which are fatty acids that like to sit very close next to each other, makes the butters be solid at room temperature! ;) ) and they determine the density of an oil.
Saturated fatty acids tend to create deposits and this might happen also on the skin. However, if they are in low percentage, there is no problem in the formulation. :)
Stearic Acid, as a lone substance, is also used as a thickener in creams and sometimes soaps; its presence however helps the formation of the unfamous white-trail, therefore do not use too much butters which contain this fatty acid in high percentage or there is a higher risk that your cream will make the white-trail on the skin! :) But don’t worry too much: the quality of the cream, however, won’t change ;)
Lauric Acid has been claimed to have antimicrobial properties.
Now to the more interesting (for our skin) Unsaturated fatty acids, if you know a little bit of Chemistry you will already know that the shape of UNsaturated fatty acids makes it difficult for them to sit close close to each other, like the saturated fatty acids. This is why the oils, which contain mostly Unsaturated fatty acids, are liquid at room temperature :)
Now I am just going to sum up what I have read on the internet, on many studies that I have found (plus: I believe these studies because my experience also agrees :) ): apparently on the skin of people with acne there seems to be a difference in the ratio between saturated and unsaturated fatty acids, compared to people with normal skin. What is even more interesting is that also within the category of Unsaturated fatty acids there are some differences: the Monounsaturated (therefore Oleic Acid and Palmitoleic Acid) seem to be in higher percentage, while the Poliunsaturated fatty acids (linoleic and alpha-linoleic acids) seem to be in lower percentage. Therefore what I do, in the formulation, when I need to make a cream for a friend who suffers of acne is this:
I use very low percentage of butters (0.5-1%, but even this small amount is needed for the consistency of the cream) and then, when I have to pick the oils, I pick them with different densities but I make sure that they are low in Oleic and Palmitoleic Acids, while they are rich in Linoleic and Alpha-Linoleic Acids. This is what I have done and so far I had good results :)
Online you can very easily find schemes about even the most exotic oils! You will easily find data about their density and also their fatty acids content!
Here I will just sum up very easily which oils are higher in content of linoleic and alpha-linoleic acids compared to the monounsaturated oils.
Black currant oil
Grape seed oil
Passion fruit oil
Hope this was helpful to some of you :)
I am sure there would be more and more things to know about fatty acids but this is what I have found so far.
If you have higher knowledge, please feel free to share in the comments! :) I am always very glad to learn new useful things!
Have a great day! ;)