The world of oils is vast and varied, for that reason I am always trying to organize them in my mind, to help me know what to reach for when developing a new formula.
I have several ways of studying the oils, but possibly the best way to organize them is by the dominant fatty acids in each oil. We could spend weeks diving into the subject of fatty acid families, but for now I just want to look at the differences between the fatty acid groups, so that you can start building your relationship with the oils!
Fatty Acid Families
There are two main types of fatty acids: saturated fatty acids and unsaturated omega fatty acids.
Saturated fatty acids are solid at room temperature. These are your shea butters, coconut oil, mango butter and cocoa butter. This group is large and varied, but small compared to the omega fatty acid group. The omega fatty acid group includes both monounsaturated fatty acids and polyunsaturated fatty acids. Notice both are unsaturated.
The difference between these two are number of double bonds on the fatty acid chains; mono meaning one double bond on the chain of carbons and poly meaning more than one, all the way up to five double bonds on the carbon chains.
If you didn't major in chemistry in college, don't worry, I didn't either! The oils taught me basic chemistry, it was through working with them, and studying them that I began to learn these concepts. As you work with the oils and study them it will all make sense.
Let's look at the saturated fatty acids and how we use them in skincare first.
Saturated fatty acids belong to a family of their own. They range from very short, four carbons up to very-long lengths of carbon atoms, 24 and above. Fatty acids include stearic and palmitic that make up most of the solid butters like cocoa butter, shea butter, mango butter and coconut oil.
In skincare formulas these saturated fatty acids protect the skin. They don't penetrate deeply into the skin layers but rather sit on top of the skin, forming a light protective layer against against wind, cold, and even sun in many instances.
Saturated butters are solid at room temperature because they have high percentages of saturated fatty acids. But all oils and butters are a combination of different fatty acids. The percentages of each are what determine the character of the oil.
Monounsaturated fatty acids
Omega 9 family contains multiple monounsaturated fatty acids. The most common of which is oleic acid.
Oleic acid - which gets its name from olive oil - is found in all oils in some measure, including olive oil, avocado oil, camellia seed oil, almond oil, and apricot kernel oil. Monounsaturated fatty acids have an absorption rate slightly higher than saturated chains and so they also protect the skin from moisture loss.
On the skin, oleic acid helps maintain suppleness, flexibility, and softness. Oleic acid moisturizes by creating a fine protective film of nourishing monounsaturated fatty acids on the skin surface. Anti-inflammatory and regenerative properties maintain the health of the skin and its affinity with healthy skin function makes oleic acid important for good skin care.
Other omega 9 fatty acids include ricinoleic acid found in castor oil, and the very-long chained C20:1 and Erucic acid C22:1 found in rapeseed oils.
Omega 7 also monounsaturated, with its most important member palmitoleic acid C16:1. Found in all tissues, palmitoleic acid is an important part of skin lipids. Produced by the sebaceous glands, palmitoleic acid forms about 20% of sebum and protects against infectious agents while its antimicrobial actions maintain healthy skin functions.
Found in many oils at very small percentages of around 1% it is generously supplied in a few: macadamia nut, sea buckthorn fruit, and avocado oils. The production of palmitoleic acid in the skin decreases with age, so it’s an excellent fatty acid supplement for mature skin care.
Polyunsaturated Fatty Acids
Omega 6 linoleic acid, C18:2, as one of two essential fatty acids is a particularly important fatty acid and plays a crucial role in maintaining the barrier and passage functions of the skin. Omega 6 fatty acids absorb well into the skin layers and plays an important role in our health. Grape-seed, safflower, evening primrose, and passion fruit seed oils are high in linoleic acid.
The barrier and passage functions of the skin must be optimal, able to absorb or repel according to environmental conditions or current skin needs. Harmful bacteria, chemicals, and plain old dirt are kept out when these functions are working properly, while moisture and nutrients, including fatty acids, are absorbed into the skin layers.
Gamma-Linolenic acid, GLA, C18:3, also an omega-6 fatty acid, is not an essential fatty acid, as it can be made from linoleic acid, but plays an important part in maintaining the health of the skin and body.
Anti-inflammatory and immune supporting properties soothe redness, irritation, and itching.
GLA helps heal damaged and broken skin and minimizes scarring by supplying nutrients to the skin necessary for regenerating skin cells.
Found in evening primrose, borage and black currant seed oils.
Omega 3 alpha-Linolenic acid, C18:3, is particularly vital to the health of the skin and body. Anti-inflammatory and internally protective of the circulatory system, this fatty acid performs functions important for healthy skin. As the essential fatty acid responsible for curbing inflammation, LNA helps to relieve itching, redness, and skin irritation. Protective, nourishing, and very light, oils with high ratios of both essential fatty acids, GLA and LNA, absorb quickly and easily into the skin. Produced primarily in seeds, high percentages of LNA are found in red raspberry, walnut, blackberry, chia, and flax seed oils.
The omega 3 oils have similar health giving properties that the fish oils do and are especially important for maintaining a balanced inflammatory response in the body.