The surface of your skin is covered by a layer of beneficial fats, including epidermal lipids and sebum.
These beneficial fats leave your skin feeling soft, smooth and plump.
This article will discuss:
- What is the skin barrier?
- What is the lipid barrier?
- Epidermal lipids in the lipid barrier
- Free fatty acids in the lipid barrier
- Sebum in the lipid barrier
- What are beneficial lipids?
- What are natural sources of beneficial lipids?
- Hemp seed oil
- Apple seed oil
- What is linoleic acid?
- What are the benefits of linoleic acid?
- What are emollients?
- What are the benefits of emollients?
- How do beneficial fats repair the lipid barrier?
- References
What is the skin barrier?
The skin barrier is essentially what you can see and touch on the surface of your body.
When your skin barrier is healthy, it feels and appears smooth, soft, and plump.
In contrast, a damaged skin barrier looks dry, rough, dull, and dehydrated, and may become irritated and inflamed.
The skin barrier includes the outermost layers of skin, called the stratum corneum.
The stratum corneum can be thought of as a brick wall that protects you.
The "bricks" are the skin cells, called corneocytes, and the "mortar" that holds the bricks together is the lipids or fats, that together create the outer barrier.
Learn More: What is The Skin Barrier?
What is the lipid barrier?
The lipid barrier is a part of your skin barrier.
The surface of your skin is covered by a layer of protective fats, including epidermal lipids and sebum.
- Epidermal lipids include:
- Ceramides
- Free fatty acids
- Cholesterol
- Sebum is made of:
- Triglycerides
- Wax esters
- Squalene
Theses beneficial fats and lipids are naturally found in the lipid barrier and skin barrier and play a critical role in keeping your skin healthy.
Epidermal lipids in the lipid barrier
Epidermal lipids are a mixture of ceramides, free fatty acids and cholesterol.
- Epidermal lipids include:
- Ceramides
- Free fatty acids
- Cholesterol
These lipids are released from skin cells and fill the spaces between the cells, like mortar or cement (Pappas, 2009).
The stratum corneum lipids consist of an equimolar mixture of ceramides (45–50% by weight), cholesterol (20–25%), and free fatty acids (10-15%), with lower quantities of cholesterol sulfate and nonpolar lipids (Verdier-Sévrain et al, 2007).
Free fatty acids in the lipid barrier
There are beneficial free fatty acids found in your stratum corneum, or outer skin barrier.
The main free fatty acids in the lamellar membranes are:
- 10% palmitic acid (C16:0)
- 10% stearic acid (C18:0)
- 15% behenic acid (C22:0)
- 25% lignoceric acid (C24:0)
- 10% hexacosanoic acid (C26:0)
(Kang et al, 2006; Lin et al, 2017).
Other free fatty acids that are also found naturally in the stratum corneum include:
- oleic acid (C18:1, n-9)
- eicosapentaenoic acid (C20:5, n-3)
- arachidonic acid (C20:4, n-6)
- docosahexaenoic acid (C22:6, n-3)
- linoleic acid (C18:2, n-6)
- α-linolenic acid (C18:3, n-3)
- γ-linolenic acid (C18:3, n-6)
- dihomo-γ-linolenic acid (C20:3, n-6)
(Lin et al, 2017).
Linoleic acid is the most abundant polyunsaturated fatty acid in the skin barrier (Ansari et al, 1970).
Most of the free fatty acids can by synthesized by the keratinocytes and are released into the stratum corneum.
However, linoleic acid and arachidonic acid are essential fatty acids that must be provided externally through diet, supplements or topically through skincare products (Lin at al, 2017).
What is sebum?
Sebum is an oily, waxy substance produced by your body’s sebaceous glands and eventually released to the surface of the skin. Sebum is primarily made up of non-polar lipids as triglycerides, wax esters and squalene. Sebum coats the skin, seals in moisture, and protects your skin from getting too dry (Pappas, 2009).
The composition of human sebum collected from the skin surface is typically 1.4% cholesterol, 16% fatty acids, 40% triglycerides, 25% wax monoesters, 2% cholesterol esters and 12% squalene (Downing et al, 1969).
What are beneficial lipids?
Beneficial lipids for your skin include fatty acids, ceramides, squalene, and cholesterol.
Beneficial lipids for your skin include fatty acids:
- linoleic acid (C18:2, n-6)
- oleic acid (C18:1, n-9)
- palmitic acid (C16:0)
Beneficial lipids are found in carrier oils that are rich in free fatty acids.
Carrier oils be extracted from nuts, grains, seeds, fruit and berries.
Carrier oils are rich in essential fatty acids, and other beneficial components for skin, such as phytosterols, vitamins, carotenoids and squalene.
Carrier oils can replenish the beneficial fatty acids found naturally in your skin barrier, including linoleic acid.
Learn more: Beneficial Fats Found Naturally in Your Skin Barrier
What are natural sources of beneficial lipids?
There are many sources of beneficial lipids, including sunflower seed oil, hemp seed oil and apple seed oil.
Hemp seed oil is rich in beneficial fats for the lipid barrier
Cold-pressed, unrefined hemp seed oil is packed with essential nutrients, including fatty acids, vitamins and antioxidants.
Hemp seed oil is rich in n-6 linoleic acid (56%), n-9 oleic acid (11%) which soften your skin and strengthen your skin barrier
Hemp seed oil contains 16% linolenic acid, an essential omega 3 fatty acid that calms redness and irritation. Hemp seed oil also contains 5% γ-linolenic acid, a unique n-6 fatty acid with potent anti-inflammatory activity.
Learn more: 5 Benefits of Hemp Seed Oil for Dry Skin
Apple seed oil is rich in beneficial fats for the lipid barrier
Apple seed oil is rich in beneficial fatty acids, including n-6 linoleic acid (60%), n-9 oleic acid (30%) and palmitic acid (7%), which can soften and smooth your skin, and strengthen your skin barrier.
Apple seed oil is rich in various forms of vitamin E and polyphenols and has strong antioxidant activity and can protect your skin against free radical damage.
Learn more: 4 Benefits of Apple Seed Oil for Dry Skin
What is linoleic acid? Essential omega 6 fatty acid
Linoleic acid is an essential fatty acid found naturally in healthy skin.
Linoleic acid is an essential nutrient, and your body must get linoleic acid through diet or supplements. Linoleic acid is essential for growth, reproduction, and skin function (Huang et al, 2018).
Linoleic acid belongs to the family of omega 6 polyunsaturated fatty acids (PUFAs).
Carrier oils rich in linoleic acid can soften, smooth and lubricate the skin.
Benefits of linoleic acid
Linoleic acid can be applied topically to your skin and has numerous benefits.
- Linoleic acid is an emollient and softens your skin
- Linoleic acid strengthens the skin barrier
- Linoleic acid improves dry skin symptoms
Learn more: What is Linoleic Acid? Omega 6 Essential Fatty Acid for Dry Skin
1. Linoleic acid softens your skin
In skincare products, linoleic acid functions as an emollient and softens your skin.
2. Linoleic acid strengthens the skin barrier
Linoleic acid is the richest polyunsaturated fatty acid in the epidermal layer. It is also the precursor to ceramide synthesis (Breiden et al, 2014).
Linoleic acid is the richest polyunsaturated fatty acid in the epidermal layer. It is also the precursor to ceramide synthesis (Breiden et al, 2014).
As an essential component of ceramides, linoleic acid is involved in the maintenance of the transdermal water barrier of the epidermis (Whelan et al, 2013).
3. Linoleic acid can relieve dry skin symptoms
Linoleic acid can relieve symptoms of dry skin.
Linoleic acid can:
- Make your skin feel soft and smooth.
- Help reduce flaking and roughness from dry skin.
- Minimize the appearance of fine lines and wrinkles.
- Reduce irritation from dry skin.
- Relieve itching from dry skin.
What are emollients?
The word emollient derives from the present participle of the Latin verb emollire, which means "to soften or soothe." Emollire, in turn, derives ultimately from mollis, meaning "soft."
Skincare ingredients that function as emollients include plant butters, vegetable and fruit oils, animal fats, and esters.
Learn more: What are Emollients? Best Emollients for Dry Skin.
What are the benefits of emollients?
The function of emollients in skincare is to soften the skin, help the skin retain its moisture and to support the skin’s barrier function.
Skin that does not have sufficient lipid content on its surface can appear dull, dry and rough. Emollients "fill in the gaps" in the skin barrier and soften it along with giving it a healthier look
The role of emollients in the treatment of dry skin conditions is often underestimated. Emollients promote optimal skin health and prevent skin breakdown, and their use can improve quality of life (Moncrieff et al, 2013; Newton et al, 2021).
Emollients are skin conditioning – the give skin a soft and smooth appearance, restoring suppleness and improving elasticity (Brown et al, 2005).
Emollients:
- Make your skin feel soft and smooth.
- Help reduce flaking and roughness from dry skin.
- Help assist the skin barrier by filling in gaps between cells.
How do beneficial fats repair the lipid barrier?
How do beneficial fats repair your lipid barrier?
The surface of your skin is covered by a layer of beneficial fats, including epidermal lipids and sebum.
Beneficial lipids can:
- Make your skin feel soft and smooth.
- Help reduce flaking and roughness from dry skin.
- Minimize the appearance of fine lines and wrinkles.
- Reduce irritation from dry skin.
- Relieve itching from dry skin.
Beneficial lipids, such as linoleic acid act as emollients, and can repair your lipid barrier.
Dry Skin Love Wild Orange Oil to Milk Cleanser is made with hemp seed oil, apple seed oil and sunflower seed oil, which are all rich in linoleic acid and other beneficial fatty acids.
Wild Orange Oil to Milk Cleanser - 5 Benefits Cleansing Oil for Dry Skin
References:
Ananthapadmanabhan KP, Mukherjee S, Chandar P. Stratum corneum fatty acids: their critical role in preserving barrier integrity during cleansing. Int J Cosmet Sci. 2013 Aug;35(4):337-45.
Ansari, M.N.; Nicolaides, N.; Fu, H.C. Fatty acid composition of the living layer and stratum corneum lipids of human sole skin epidermis. Lipids 1970, 5, 838–845.
Breiden B., Sandhoff K. The role of sphingolipid metabolism in cutaneous permeability barrier formation. Biochim. Biophys. Acta. 2014;1841:441–452.
Brown A, Butcher M. A guide to emollient therapy. Nurs Stand. 2005 Feb 23-Mar 1;19(24):68, 70, 72 passim.
Downing, D.T., Strauss, J.S. and Pochi, P.E. Variability in the chemical composition of human skin surface lipids. J. Invest. Dermatol. 53, 322–327 (1969).
Huang TH, Wang PW, Yang SC, Chou WL, Fang JY. Cosmetic and Therapeutic Applications of Fish Oil's Fatty Acids on the Skin. 2018 Jul 30;16(8):256.
Kang, L.; Ho, P.C.; Chan, S.Y. Interactions between a skin penetration enhancer and the main components of human stratum corneum lipids. J. Therm. Anal. Calorim. 2006, 83, 27–30.
Lin TK, Zhong L, Santiago JL. Anti-Inflammatory and Skin Barrier Repair Effects of Topical Application of Some Plant Oils. Int J Mol Sci. 2017 Dec 27;19(1):70.
Moncrieff G, Cork M, Lawton S, Kokiet S, Daly C, Clark C. Use of emollients in dry-skin conditions: consensus statement. Clin Exp Dermatol. 2013 Apr;38(3):231-8; quiz 238.
Newton H. Using emollients to promote safe and effective skin care for patients. Nurs Stand. 2021 Oct 6;36(10):77-82.
Pappas A. Epidermal surface lipids. Dermatoendocrinol. 2009 Mar;1(2):72-6.
Verdier-Sévrain et al. (2007). Skin hydration: a review on its molecular mechanisms. Journal of Cosmetic Dermatology, 6, 75–82.
Whelan J, Fritsche K. Linoleic acid. Adv Nutr. 2013 May 1;4(3):311-2.
Author Information
Dr. Natasha Ryz is a scientist, skin care expert and an entrepreneur. She is the founder of Dry Skin Love Skincare, and she creates skincare products for beauty, dry skin and pain relief.
Dr. Ryz has a PhD in Experimental Medicine from the University of British Columbia in Vancouver, and she is a Vanier scholar. She also holds a Master of Science degree and a Bachelor of Science degree from the University of Manitoba in Winnipeg.
Natasha is the former Chief Science Officer of Zenabis Global, and she oversaw cannabis extraction, analytics, and product development. Her team brought 20 products to market including oils, sprays, vapes and softgels.
Why I Started A Skincare Company