The Role of Natural Plant Oils In Skin Barrier Repair
We love good facial oils - their silky and luxurious feel make us feel like a million buck.
While it is widely known that facial oils could keep our skin hydrated and gives it a natural glow look, it is not widely known that some type of oils could also help with skin barrier repair!
As there are hundreds of different types of natural plant oils available in the market today, many of which are not well researched, discussing each one of them in this article will not be practical.
Instead, we will focus on properties that make a facial oil helpful for skin barrier repair and some of the popular facial oils that have these properties.
Our discussion is focused on fixed oils (oils which are not volatile in room temperature), as opposed to essential oils.
How Can Natural Plant Oils Help With Skin Barrier Repair?
To understand how natural plant oils can help with skin barrier repair, we need to first understand what skin barrier is and what it is made of.
(For a more detail discussion on skin barrier, read our previous article here).
Our skin barrier is structured like a brick wall: corneocytes (a protein) acting as the brick is surrounded by lipids (a fatty or oily substance) which act as mortars. Together, corneocytes and lipids form a waterproof barrier.
The lipids form 10-20% of the skin barrier by weight and they are made of ceramides (30-50% of the lipids), cholesterol (~25%) and free fatty acids (10-20%)1.
In comparison, fixed plant oils are made of triglycerides, free fatty acids (FFAs) and many other compounds. The FFAs can also be further differentiated into saturated fatty acids (SFAs) and unsaturated fatty acids (UFAs).
A study found that topical applications of different type of fatty acids on skin resulted in a difference in Transepidermal Water Loss (TEWL) and irritant skin response2.
For example, Linoleic Acid (a poly UFAs) is found to have a direct role in maintaining the integrity of skin barrier3. In contrast, oleic acid (a mono UFAs) is detrimental to skin barrier function4.
The amount of triglycerides, SFAs, and UFAs varies in each type of plant oil (depending on the type of plant), therefore different types of plant oils will have different impact to the skin barrier.
Plant oils that are rich in linoleic acid but low in oleic acid will work best for skin barrier repair.
Some oils, such as Jojoba oil, have low linoleic and oleic acid content but are high in other fatty acids that gives it unique property and thus also helpful for skin barrier repair.
So, Which Plant Oils Are Beneficial For Skin Barrier Repair?
Tzu-Kai Lin et al5 and Alexandra R Vaughn et al6, have made an extensive review of various studies on several plant oils and their impact on skin barrier, summarized in the table below.
Do note that the % composition of these plant oils can vary widely depending on the plants' growing conditions, climate, extraction process, and many other factors. Hence, its effect on our skin can also vary greatly.
| Oil | % Oleic acid composition | % Linoleic acid composition | % Other fatty acids | Remarks |
|---|---|---|---|---|
| Argan | 43 - 49% | 29 - 36% | 4 - 15% | Daily topical application has been shown to improve skin elasticity and restore skin barrier function. |
| Borage | N/A | N/A | N/A | Contains high level of omega-6 series essential fatty acids. Found to normalize skin barrier function in children with seborrheic dermatitis or atopic dermatitis. |
| Coconut | 5 - 10% | 1 - 2.5% | 85 - 90% | Found to be as effective as mineral oil in improving skin hydration and barrier function. It has antimicrobial property. |
| Jojoba | ~11% | ~5% | ~85% | Unique among plant oils with high wax esters content, making it close to human sebum composition. |
| Grapeseed | 12 - 22% | 65 - 85% | 2 - 10% | It has one of the highest linoleic acid contents among plant oils. Found to provide significant protection against SLS-induced irritation. |
| Hempseed | ~10% | ~52% | ~40% | N/A |
| Oat | 28 - 40% | 37 - 46% | ~23% | May stimulate ceramide synthesis. Found to be as effective as ceramide-based cream at improving TEWL in non-controlled study. |
| Rosehip | 15 - 22% | 50 - 77% | N/A | Rich in a-linoleic and linoleic acid. Contain high level of antioxidants and anti-inflammatory property. |
| Sunflower seed | ~24% | ~62% | ~5% | Shown to preserve skin barrier integrity and improve hydration. |
Fun fact: Olive oil, a popular facial oil, is found to be detrimental to skin barrier integrity, possibly due to its high oleic acid and low linoleic acid content. Some studies found it to significantly increased TEWL, decreased stratum corneum thickness and induced mild erythema7. Despite that, it has high phenolic content, potent antioxidant that is anti-inflammatory, reduces oxidative damage and inhibits skin cancer development.
Conclusion
Evidences suggest that plant oils could have immense benefits for our skin, including skin barrier repair properties.
Most of the widely known benefits of plant oils are from the oils' physical properties (their silky and lustrous feel, their function as emollient and their hydrating properties), but the potential benefits from their chemical properties have not been discussed as extensively.
Each plant oil has unique chemical composition and may have different impact to our skin. Even oils of the same type could have varying degree of chemical compositions due to factors such as differences in growth conditions, climate, and extraction process.
Our advice is as long as you like facial oils and they work for you, keep embracing it as part of your routine!
Sources
- Harding, C. R. (2004). The stratum corneum: structure and function in health and disease. Dermatologic therapy, 17, 6-15. ↩
- Tanojo, H., Boelsma, E., Junginger, H. E., Ponec, M., & Boddé, H. E. (1998). In vivo human skin barrier modulation by topical application of fatty acids. Skin Pharmacology and Physiology, 11(2), 87-97. ↩
- Elias, P. M., Brown, B. E., & Ziboh, V. A. (1980). The permeability barrier in essential fatty acid deficiency: evidence for a direct role for linoleic acid in barrier function. Journal of Investigative Dermatology, 74(4), 230-233. ↩
- Jiang, S. J., & Zhou, X. J. (2003). Examination of the mechanism of oleic acid-induced percutaneous penetration enhancement: an ultrastructural study. Biological and pharmaceutical bulletin, 26(1), 66-68. ↩
- Lin, T. K., Zhong, L., & Santiago, J. L. (2018). Anti-inflammatory and skin barrier repair effects of topical application of some plant oils. International journal of molecular sciences, 19(1), 70. ↩
- Vaughn, A. R., Clark, A. K., Sivamani, R. K., & Shi, V. Y. (2018). Natural oils for skin-barrier repair: ancient compounds now backed by modern science. American journal of clinical dermatology, 19(1), 103-117. ↩
- Southall M, Pappas A, Nystrand G, Nebus J. Oat Oil Improves the Skin Barrier. In: Johnson & Johnson Consumer Companies Inc, editor. Supplement to The Dermatologist; 2012. ↩
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