Crash Course on Carrier Oils
**Note: I am by no means an expert and the below is what I’ve researched, gathered and/or learned up until now (and will keep adding info as I keep learning). This is by no means a detailed account on carrier oils (vegetable or base oils) and chemistry is not my forte, which is quite necessary to understand the nature of oils. I’m trying my best but there might be mistakes in the information below. Please do double check with other sources while I better this page as I go along. Thank you : )
About Carrier Oils
As a natural skincare formulator I need to learn as much as I can about all the ingredients I use to make my skincare products. I understand there always be lots more to learn, but I think it’s a good idea for me to leave these ‘crash courses’ available on the site as basic info pages others can use to learn the basics as well. And for me to use as quick guide-refreshers as well.
The term ‘carrier oil’ is used to identify base or fixed oils (lipid oils is actually the technical term – lipid means ‘fat’) from essential oils. They are called ‘fixed’ because they don’t evaporate, like essential oils do. We use the term ‘carrier’ because we use these base oils to ‘carry’ essential oils into our body. Essential oils also get diluted this way.
Carrier oils are extracted from the seeds of the plants. Examples of carrier oils would be olive, avocado, hemp, peach kernel or flaxseed oil. Examples of essential oils would be lavender, melissa (lemon balm), neroli, peppermint, eucalyptus or frankinsence essential oils. Of course, there are many, many carrier oils and many, many essential oils.
Essential oils are not true oils as they evaporate (being volatile they’re dispersive). They also have aromatic compounds. Unlike lipid oils, essential oils don’t contain minerals, proteins, vitamins or fats. Carrier oils do.
Carrier oils are as unique as the plants that produce them. They’ll also be different according to each plant even when the plant is the same. So the oil will change plant to plant, which is truly fascinating.
Carrier Oil Properties: What Makes them So Precious?
Vegetable oils have numerous properties and are beneficial for external and internal use. There are so many different carrier oils you can try nowadays, many different products that are being sold by suppliers all over the world.
Here’s a list of vegetable oil’s general properties:
- REGENERATIVE PROPERTIES: This is the reason why carrier oils are widely used in natural cosmetic products. They can hep reduce wrinkles and fine lines, they can help reduce eye puffiness, they make great facial cleansers, etc.
- EMOLLIENT PROPERTIES: Carrier oils can help reduce inflammation, redness and itching. They can heal damaged skin.
- HAIR PROTECTION: There are many carrier oils that are highly nutritional for the hair and are perfect for treating certain hair problems as well as fighting external factors.
- SOFTENING PROPERTIES: Carrier oils can soften skin and hair. Some oils are also suitable for people with sensitive skin or allergies.
- MOISTURISING PROPERTIES: Carrier oils can provide elasticity to the skin and regulate sebum production.
On Oil Composition
Oils are made of:
1) Triglycerides (the oily lipid part) – Triglycerides consist of 3 fatty acids attached to a glycerol. Triglycerides are the fatty acids [see below] organised into larger molecules.
The different fatty acids make up for at least 95% of each oil (and all the way to 99%). It is because all these fatty acids are different that they behave different on the skin as well.
2) A tiny portion of ‘non-oily’ or ‘non-lipid’ plant compound. This tiny bit of plant (non-lipid) compound will be responsible for things like the colour or smell of the oil together with antioxidants, minerals, vitamins, etc. These are the unsaponifiables.
About Fatty Acids
Fatty acids are carbon chains (they can have different lengths) with a carboxyl group, COOH or CO2H at one end (Delta end) and at the other end we find methyl group (Omega free end). At the delta end, a glycerol molecule binds the fatty acids together (the bound fatty acids form the triglycerides).
Fatty acids have two “ends”; the carboxylic acid (COOH) group is on one end, and this carbon is designated as the α (alpha) carbon. The other end of the molecule has a methyl (CH3) group, and this carbon is designated as the ω (omega) carbon.
Source
All oils are made up of many different fatty acids (35 or more). One oil can comprise the same fatty acid in the triglyceride, it can contain mixed triglycerides of multiple fatty acids and fatty acids can vary. In fact, between the two ends (Delta and Omega) the carbon chains can vary in length, in shape, they can be saturated or unsaturated, etc. But all oils have their very own fatty acid profile unique to them.
Helpful: How do you determine the α and ω ends in fatty acids? and A quick introduction to fatty acids.
Fantastic video on the molecular structure of triglycerides here.
Saturated & Unsaturated Fatty Acids that Make Up All Oils
Saturated Fatty Acids
Straight carbon chains (long or short), carbon atoms strung together with 2 hydrogens attached to the carbon (saturated with hydrogen). They’re evenly attached to hydrogens (that’s why they’re straight carbon chains). This would make it a solid type of oil. An example would be cocoa butter, shea butter, mango butter.
Unsaturated Fatty Acids
Along the carbon chain we find it breaks as it’s missing hydrogen in one place (mono-unsaturated fatty acids), two or more places (poly-unsaturated fatty acids). Because the carbon chain is missing hydrogen the chain bends. When we have a lot of unsaturated fatty acids together they stand apart from each other, and that’s how we get the oils to be liquid.
Oxygen attachs where the hydrogen is missing which is what makes the oils con rancid.
Video on saturated fats, unsaturated fats and trans fats here.
Examples of What Fatty Acids are Good For
Palmitoleic acid is an important monounsaturated fatty acid and especially good for the skin.
Linoleic acid is an essential fatty acid recommended for troubled skin.
Alpha-linolenic acid, LNA and gamma-linolenic acid or, GLA oils are particularly good to help control inflammatory conditions of the skin.
About Oxygen, Oxidation & Shelf Life
Oxygen will attach to carbon atoms that have not been saturated with hydrogen. It is the cause for oils going rancid but also it helps oils dry fully. This is such a massive plus when it comes to the skin! Oxygen is what makes the carboxyl group an acid. Oxygen will change the nature of the fatty acid causing it to oxidise over time.
The more unsaturated an oils is the quicker it’ll go rancid (less shelf life). Monounsaturated oils can last for up to one year but they have to be properly stored. Time, heat, light and air are responsible for oils going rancid. The more double bonds in a carbon chain, the more oxygen that will attach to it, the more the oils is prone to oxidation.
List of Fatty Acids
The most common fatty acids are: palmitic acid (C16:0), stearic acid (C16:0), oleic acid (C16:0), linoleic acid (C16:0), alpha-linoleic acid (C16:0).
Find below a few lists on fatty acids. Here’s Wikipedia list on saturated fatty acids and on unsaturated fatty acids.
Short Chain Fatty Acids
- C3:0 Propionic Acid
- C4:0 Butyric Acid
- C5:0 Valeric Acid
Medium Chain Fatty Acids
- C6:0 Caproic Acid
- C7:0 Enanthic Acid
- C8:0 Caprylic Acid
- C9:0 Pelargonic Acid
- C10:0 Capric Acid
- C11:0 Undecylic Acid
- C12:0 Lauric Acid
Long Chain Fatty Acids
- C13:0 Tridecylic Acid
- C14:0 Myristic Acid
- C15:0 Pentadecylic Acid
- C16:0 Palmitic Acid
- C16:1 Omega-7 Palmitoleic Acid
- C17:0 Margaric Acid
- C18:0 Stearic Acid
- C18:1 Omega-9 Oleic Acid
- C18:1 Omega-7 Vaccenic Acid (Trans)
- C18:1 Omega-9 Elaidic Acid (Trans)
- C18:2 Omega-6 Linoleic Acid
- C18:2 Ximenynic Acid (Trans)
- C18:3 Omega-3 a-Linolenic Acid
- C18:3 Omega-6 gamma-Linolenic Acid
- C18:4 Omega-3 Stearidonic Acid
- C19:0 Nonadecylic Acid
- C20:0 Arachidic Acid
- C20:1 Omega-7 Paullinic Acid
- C20:1 Omega-9 Gondoic Acid
- C20:3 Omega-6 Dihomo-Omega-linolenic Acid
- C20:3 Omega-9 Mead Acid
- C20:4 Omega-6 Arachidonic Acid
- C20:5 Omega-3 Eicosapentaenoic Acid
- C21:0 Heneicosylic Acid
Very Long Chain Fatty Acids
- C22:0 Behenic Acid
- C22:1 Omega-9 Erucic Acid
- C22:4 Omega-6 Docosatetraenoic Acid
- C22:6 Omega-3 Docosahexaenoic Acid
- C23:0 Tricosylic Acid
- C24:0 Lignoceric Acid
- C24:1 Omega-9 Nervonic Acid
About Long Chain Fatty Acids
Oils degrade over time and go rancid. The factors that contribute to oils going rancid are: time, heat, air and light. The antioxidants in unsaponifiables (below) can help delay rancidity in oils but very long saturated fatty acids (20 carbons long and more) can also help protect the oils.
Obviously these acids have to be present in a considerable amount to make the difference. Interesting to note is that these oils, when mixed with other oils, can protect them against rapid rancidity as well.
A long polyunsaturated acid is between 14 and 18 carbons (see above). These oils will go rancid quite quickly. Jojoba oil and meadowfoam oil have very long carbon chains and they can be used to mix with ‘weaker’ oils to protect them against rancidity and preserve them thus giving them longer lifespan. I use Meadowfoam carrier oil in most of my oil blends for this very reason. The good thing about both jojoba and meadowfoam oil (which are very similar in fatty acid composition as they both have monounsaturated eicosenioic acid C20:1 as their dominant fatty acid) is that both are also very similar to human sebum so they’ll also be beneficial for ANY skin type! They both also have anti-inflammatory properties.
Other stable oils besides meadowfoam and jojoba are: abyssinian seed oil (65% very long chains), broccoli seed oil (55% very long chains), camelina oil (18% very long chains), moringa oil (16% very long chains).
Unsaponifiables (Non-Fatty Acids) or ‘Healing Fraction’: Not Fatty Acids!
All oils have unsaponifiables (literally, the ‘bits’ that can’t be turned into soap). If you go back to the ‘On Oil Composition’ chapter above, you’ll see I mentioned that oils are made up of triglycerides and a tiny portion of ‘non-oily’ or ‘non-lipid’ plant compound. These are the bits that can’t be turned into soap, the unsaponifiables (to saponify is to turn into soap).
What are these ‘bits’ of oil? Well, the unsaponifiables are the bits (compounds) that determine colour, scent, we find here the minerals, vitamins, flavonoids, squalene, antioxidants, terpenes, terpenoids, tannins, phytosterols, lignans, carotenoids, etc etc. As we can see, although the unsaponifiable part of an oil can be quite small, they are very important. Let’s have a look at this below.
Unsaponifiables and Colour
As we learned before, unsaponifiables are the non-fatty acid portion of the oil (the healing fraction). Only fatty acids can turn into soap. Unsaponifiables, though, play a very important role when it comes to oils, even though they usually come at 2% or less in most oils.
Unsaponifiables don’t turn into soap when the oil is mixed with lye. We can learn from the colour of the oils, something unsaponifiables are responsible for.
Violet, blues and other similar colours are pigments that can be found in the tissues of the plants. These compounds usually (not always) contain ‘cyan’ which is a shade of blue. These ‘blue’ flavonols have high antioxidant properties. Think blueberries!
The colours yellow and green are due to xanthopylls compounds (think broccoli or avocado). Two oils rich in these compounds are cranberry seed and marula oil.
Orange beta-carotene compounds are great for the skin and eyes. They’re fantastic antioxidants and protect against ultraviolet rays. Red oils are red palm oil, rose hip seed oil, buriti oil. Other oils can be less colourful but still contain beta-carotene.
Red colour: tomatoes, cherries, pomegranate and rose hips have in common lycopene compound (part of the carotenoid group). Lycopene is a very powerful antioxidant.
Yellow colour: flavonoids are responsible for the colour (although not all flavonoids are yellow). Sea buckthorn and pomegranate have flavonoids. Included are anti-allergenic, anti-inflammatory and anti-microbial properties.
Polyphenols
Polyphenols (also known as phenolics) are phytochemicals compounds that have antioxidant properties (more on this below, under PHYTONUTRIENTS). Antioxidants, in fact, can be divided into 3 groups:
- Carotenoids
- Allyl Sulfides
- Polyphenols
Vitamins
Unsaponifiables can contain vitamins, which are extremely important as they are essential nutrients.
Vitamin A is a fat soluble vitamin. It is formed in the body from pro-vitamin A oil soluble carotenes. Carotenoids (precursors of vitamin A), cannot be synthesized by the body. The oils can be quite orange and are great at fighting free radicals. They also protect against sun rays. Some oils are buriti, sea buckthorn berry, palm and carrot seed oil.
Vitamin D is actually created in the dermis – the middle skin layer – when the sun’s rays act on the fatty sterols cholestero. In fact, we need the sun in order to activate function. The sun needs to touch our skin without sunscreens which would block this. In fact, natural vegetable oils on our skin help to facilitate the transformation. Please note that Vitamin D is not found in vegetable oils per se. Vitamin D helps with inflammation, helps strengthen the bones, regulates our immune system. Calcium is regulated in the blood thanks to ‘calcitriol‘, produced in the skin with the help of induced photo-synthesis thanks to the sun.
Vitamin E is really fat soluble and it protects against oxidation. Forms of the vitamin are tocopherols, tocotrienols and tocomonoenol. Tocopherols consist of 4 types: alpha (α-), beta (β-), gamma (γ-) and delta (δ-). These are potent antioxidants and protect the skin from free radical damage and UV exposure. Tocotrienols can be more effective antioxidants than tocopherols by 40 to 60 times. Oils with tocotrienols: wheat germ oil and rice bran oil amongst others. Tocomonoenol is found in palm oil.
Tannins
Tannings are astringent compounds that help tissues tighten, pucker and toughen by constricting them, helping the skin against external invasions (think of animal hides turned into leather). They support the health of tissues and are the ones in charge of aiding skin protein to harden as well as dry. They are anti-inflammatory, anti-viral and anti-bacterial. Oils high in tannins absorb easily into the skin. Camellia oil (lovely as part of a facial serum), jojoba oil, rose hip seed oil are all high in tannins and so they dry quickly after application on the skin.
Tannin compounds help tissues tighten and oils high in tannin feel ‘less oily’. These oils can be used to help oily skin as the skin won’t feel the need to produce an excess of oil. Jojoba oil (a wax) is a good example of this.
Combining oils high in tannins together with essential oils for oily skin will help with sabaceous glands that tend to be over-active.
Some oils high in tannins are rosehip seed oil, camelia oil, grapeseed oil, hazelnut oil, jojoba oil and cranberry oil.
Dry Oils & Drying Oils
Drying oils dry when touching them as time goes by.
Dry oils simply feel dry, meaning they don’t feel oily on the skin. They’re mainly oils with astringent properties which means they will tighten tissues and reduce pore size.
Oils that Help Repair the Skin
Some oils are very good at helping the skin repair itself. Polyphenols, minerals, vitamins, antioxidants, etc all help the process and some oils are just fantastic at aiding this. Some healing oils are: tamanu oil, sea buckthorn seed oil, black seed oil and hemp oil. I use black seed and hemp for a formula that helps with conditions like psoriasis.
Phytonutrients
Although not strictly related to carrier oils, I felt it was important to mention phytonutrients as many of the oils do carry them. Also because of having antioxidant and anti-inflammatory properties I felt they were important to mention on this entry. (A great article on phytonutrients here)
Phytonutrients are natural chemicals or compounds produced by plants. They keep plants healthy, protecting them from insects and the sun.
Source
There are more than 25,000 phytonutrients found in plants and the most important ones are:
- Carotenoids
- Ellagic acid
- Flavonoids
- Resveratrol
- Glucosinolates
- Phytoestrogens
Caretonoids provide the yellow, red and orange colours in fruit and vegetables and act as antioxidants fighting free radicals. The types of caretonoids are: alpha-carotene, beta-carotene, and beta-cryptoxanthin and our body can convert them into Vitamin A.
Ellagic acid is found in berries and pomegranate. “Ellagic acid can help protect skin from oxidative stress induced by UV radiation and the natural aging process […] ellagic acid applied to sun damaged skin (a mild sunburn) reduced inflammation […] these properties encourage the maintenance and/or improvement of the skin’s elasticity, which may result in the diminishing of fine lines and wrinkles. […] ellagic acid is also an effective skin brightener.” Source.
Flavonoids include Catechins, Hesperidin, Flavonols,Resveratrol, Glucosinolates, Phytoestrogens.
Oil Refining
Oils can get refined and the refining process can vary as some processes deal with removing the unsaponifiables, other processes deal with removing scent or to extend the shelf life of an oil. This is known as RBWD. It is recommended that you know what processes your oils have gone through prior to purchasing. Here’s the refining terms:
R – removes waxes, sterols, etc.
B – bleaching that neutralises free fatty acids (removes colour).
W – winterising so oils don’t harden or freeze in the winter (removes waxes)
D – deodorising to remove scent (by distillation)
Butters
Solid saturated butters include: shea butter, cocoa butter, mango butter, kukui nut butter, coconut oil, etc and are found around the tropics area. If you think logically, to guard against such heat the fat needs to be solid so its level of protection is as high as possible (this is something I’ve thought about many times). Being from the Canary Islands (very hot weather in the summer) I ‘naturally’ understand this, almost as if my DNA intelligently knows this to be a fact. My hair, for example, tends to be very curly and very dry (protects the scalp from the sun) so, in order to moisturise it properly, it would need to be treated with solid fats (think shea butter) to keep it healthy and looking shiny, rather than dull and ‘dead-ish’. This is just one example. Solid butters can also protect the skin from intense sun rays as they can act as an occlusive.
Occlusive agents are generally made up of large molecules that are unable to penetrate the skin. Rather than sinking into the skin, they sit right on the surface, acting like a protective layer. […] Shea butter, mango butter, and cocoa butter are some of the most common occlusive agents.
Source
Butters are solid because they have a high percentage of saturated fatty acids, unlike the liquid oils which have a high percentage of unsaturated fatty acids (more info on this here).
Mixing butters with carrier oils will create products that end up being more solid like balms and salves (as they help stiffen the product) although you have to remember that higher temperatures will make butters go liquid, depending on their melting point. If you’d like to check some butters’ melting point visit this link.
Skin’s Sebum & Fatty Acids
I wanted to add this section because I find it important to know the amount of fatty acids that our skin produces. This helps understand fatty acid composition within the skin, especially if you add carrier oils to your DIY skincare, which I’m sure you do.
Palmitic saturated fatty acid – Dominant fatty acid in our skin, makes up 22% of sebum in our skin. It has anti-microbial properties that help protect against infection and protects from loss of moisture and any harm to the stratum corneum.
Stearic saturated fatty acid – Acts as barrier Sealing the skin and protects from invasion, making up 11% of sebum in our skin.
Oleic mono-unsaturated fatty acid – Olive oil and almond oil are examples of carrier oils high in oleic fatty acid, which protects and nourishes our skin. It also has anti-inflammatory properties. Prevents moisture loss (not quickly absorbed). The skin is made up of 30% oleic fatty acid.
Palmitic mono-unsaturated fatty acid – An omega-7 fatty acid. The skin produces it as 20% of the total fats. Good for ageing skin, as the production of this fatty acid slows down over the years. The acid helps make the skin look younger.
Other fatty acids:
Linoleic polyunsaturated fatty acid, alpha-linolenic polyunsaturated fatty acid, gamma-linolenic polyunsaturated fatty acid. More info on fatty acids here.
Some Thoughts
I’m just starting in my ‘carrier oil career’ and there’s much to learn, that’s for sure. I’ll be adding more information to this post as I go along. The idea is to create ‘crash courses’ within the natural skincare, herbal remedies and aromatherapy worlds that I can use as reminders for myself but they can also help others.
Leave in your comments whatever else you think needs to go on this post, thanks!
