Omega-6 are a family of essential fatty acids that the human body cannot produce on its own, so they must be obtained through diet or topical products. Omega-6 fatty acids play a crucial role in maintaining skin health, thanks to their moisturizing, regenerative, and anti-inflammatory properties. One of the most notable omega-6 fatty acids is linoleic acid, which is found in many vegetable oils, such as sunflower and safflower oil. Omega-6 fatty acids support the skin barrier function, improving its ability to retain moisture and protect against external irritants.

Chemical Composition and Structure

Omega-6 fatty acids are polyunsaturated fats characterized by a double bond positioned between the sixth and seventh carbon atoms from the end of the chain (hence the name "omega-6"). Linoleic acid is the most representative member of this family and is abundant in vegetable oils like sunflower oil, safflower oil, and soybean oil. Other omega-6 fatty acids include gamma-linolenic acid (GLA), found in borage oil and evening primrose oil, which offers additional benefits for skin regeneration and elasticity support.

Physical Properties

They are typically present in the form of liquid oils that are liposoluble and either clear or pale yellow in color. Like other unsaturated fats, they are prone to oxidation, so they must be protected from light, heat, and air to preserve their stability. These oils are easily incorporated into cosmetic products such as serums, oils, lotions, and moisturizers, where they act as powerful emollients and skin regenerators.

Production Process

Omega-6 fatty acids are extracted from vegetable oils through cold pressing or supercritical CO₂ extraction processes to preserve the integrity of the fatty acids. After extraction, omega-6s are refined and stabilized for use in cosmetic products and dietary supplements. The extraction process requires care to maintain the chemical quality and stability of the fatty acids. 

• Selection of Raw Materials: Omega-6s are primarily extracted from plant sources such as soybean, sunflower, corn, and canola oils. These sources are selected for their high content of linoleic acid, the most common Omega-6 fatty acid.

• Extraction: The extraction of Omega-6s occurs through appropriate methods, such as cold pressing or solvent extraction. In cold pressing, the seeds are mechanically pressed to obtain the oil, while in solvent extraction, the plant materials are immersed in a solvent to dissolve the oils.

• Filtration: After extraction, the obtained oils are filtered to remove undissolved solids and impurities, resulting in pure, high-quality oils.

• Refining: The extracted oil may be refined to remove further impurities and improve the flavor and appearance of the final product. This process may include deodorization and bleaching.

• Hydrolysis (If Necessary): In some cases, Omega-6s can be isolated through hydrolysis of the extracted oils, using specific acids or enzymes to break down triglycerides and release the fatty acids.

• Quality Control and Packaging: Finally, Omega-6s undergo quality control checks to verify their purity, efficacy, and compliance with standards. After analysis, they are packaged in appropriate containers for distribution and use in cosmetic products and dietary supplements.

Applications

• Skincare: Omega-6 fatty acids are widely used in moisturizers for their emollient properties, improving skin barrier function and reducing transepidermal water loss, making them ideal for dry or sensitive skin.

• Anti-inflammatory Products: Thanks to their soothing properties, omega-6 fatty acids are used to reduce skin inflammation and irritation, especially in conditions like dermatitis and eczema.

• Regenerative Products: Omega-6s like GLA promote cell renewal and improve skin elasticity, making them beneficial for repairing damaged and aging skin.

These fats lower the content of harmful LDL cholesterol, exert cardioprotective and anti-inflammatory action.

Health and Safety Considerations

Safety in Use
Omega-6 fatty acids are considered safe for use in cosmetic products and dietary supplements. They are well tolerated by the skin and do not present irritation risks. Major regulatory authorities, such as the European Union and the FDA, approve their use in skincare products.

Allergic Reactions
Allergic reactions to omega-6s are rare. However, as with any natural ingredient, it is advisable to perform a patch test before use on sensitive or reactive skin.

Toxicity and Carcinogenicity
They are considered beneficial for skin health due to their ability to nourish and protect the skin barrier.

Environmental Considerations
Omega-6 fatty acids are derived from vegetable oils, which are renewable resources often cultivated sustainably. The extraction and processing of these oils can be done using eco-friendly techniques, making omega-6s a biodegradable and environmentally responsible ingredient.

Regulatory Status
Omega-6 fatty acids are approved for use in cosmetic products and dietary supplements by major regulatory authorities, such as the European Union and the FDA in the United States. They are widely used in skincare products, particularly in moisturizing and regenerative formulations.

Omega-6 studies

Araujo P, Belghit I, Aarsæther N, Espe M, Lucena E, Holen E. The Effect of Omega-3 and Omega-6 Polyunsaturated Fatty Acids on the Production of Cyclooxygenase and Lipoxygenase Metabolites by Human Umbilical Vein Endothelial Cells. Nutrients. 2019 Apr 27;11(5):966. doi: 10.3390/nu11050966.

Abstract. Although the correlation between polyunsaturated fatty acids (PUFA) and the production of pro- and anti-inflammatory metabolites is well documented, little is known about the simultaneous effect of different PUFA on the production of cyclooxygenase and lipoxygenase metabolites. The present research examines the association between different omega-3 (ω-3) and omega-6 (ω-6) PUFA and the release of four cyclooxygenase and six lipoxygenase metabolites in cell medium by human umbilical vein endothelial cells (HUVEC). The different combinations of ω-3 and ω-6 PUFA were prepared according to a full 24 factorial design that enables studying not only the main effects but also the different interactions between fatty acids. In addition, interactions diagrams and principal component analysis were useful tools for interpreting higher order interactions. To the best of our knowledge, this is the first report addressing the combined effect of ω-3 and ω-6 PUFA on the signaling of prostaglandins, prostacyclins, leukotrienes and resolvins by HUVEC.

Hooper L, Al-Khudairy L, Abdelhamid AS, Rees K, Brainard JS, Brown TJ, Ajabnoor SM, O'Brien AT, Winstanley LE, Donaldson DH, Song F, Deane KH. Omega-6 fats for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev. 2018 Nov 29;11(11):CD011094. doi: 10.1002/14651858.CD011094.pub4. 

Abstract. Background: Omega-6 fats are polyunsaturated fats vital for many physiological functions, but their effect on cardiovascular disease (CVD) risk is debated. Objectives: To assess effects of increasing omega-6 fats (linoleic acid (LA), gamma-linolenic acid (GLA), dihomo-gamma-linolenic acid (DGLA) and arachidonic acid (AA)) on CVD and all-cause mortality....Authors' conclusions: This is the most extensive systematic assessment of effects of omega-6 fats on cardiovascular health, mortality, lipids and adiposity to date, using previously unpublished data. We found no evidence that increasing omega-6 fats reduces cardiovascular outcomes other than MI, where 53 people may need to increase omega-6 fat intake to prevent 1 person from experiencing MI. Although benefits of omega-6 fats remain to be proven, increasing omega-6 fats may be of benefit in people at high risk of MI. Increased omega-6 fats reduce serum total cholesterol but not other blood fat fractions or adiposity.

Hoge A, Tabar V, Donneau AF, Dardenne N, Degée S, Timmermans M, Nisolle M, Guillaume M, Castronovo V. Imbalance between Omega-6 and Omega-3 Polyunsaturated Fatty Acids in Early Pregnancy Is Predictive of Postpartum Depression in a Belgian Cohort. Nutrients. 2019 Apr 18;11(4):876. doi: 10.3390/nu11040876. 

Abstract. While studies revealed that the omega-3 polyunsaturated fatty acids (n-3 PUFA) and their mediators would be able to regulate several biological processes involved into the development of postpartum depression (PPD), evidence from observational studies remains mixed. The aim of the present study was to investigate the association between maternal erythrocyte n-3 PUFA, measured in early pregnancy, and the risk of PPD. A Belgian cohort of 72 healthy women was screened. Erythrocyte fatty acids were analysed using gas chromatography. PPD was assessed using the Bromley Postnatal Depression Scale by phone interview one year after delivery. We observed a significant negative association between docosahexaenoic acid (DHA) levels and the risk of postpartum depression in the adjusted model (p = 0.034). Higher n-6/n-3 and arachidonic acid (AA)/eicosapentaenoic acid (EPA) ratios were significantly associated with an increased odds of PPD (p = 0.013 and p = 0.043, respectively). Women with an omega-3 index <5% had a 5-fold increased risk of depressive episode than did those with an omega-3 index ≥5% (OR 5.22 (95%CI 1.24-21.88)). A low n-3 PUFA status, alone and combined with high n-6 PUFA status, in early pregnancy was associated with a greater risk of PPD. Management of maternal n-3 PUFA deficiency can be a simple, safe and cost-effective strategy for the prevention of this major public health issue.

Marklund M, Wu JHY, Imamura F, Del Gobbo LC, Fretts A, de Goede J, Shi P, Tintle N, Wennberg M, Aslibekyan S, Chen TA, de Oliveira Otto MC, Hirakawa Y, Eriksen HH, Kröger J, Laguzzi F, Lankinen M, Murphy RA, Prem K, Samieri C, Virtanen J, Wood AC, Wong K, Yang WS, Zhou X, Baylin A, Boer JMA, Brouwer IA, Campos H, Chaves PHM, Chien KL, de Faire U, Djoussé L, Eiriksdottir G, El-Abbadi N, Forouhi NG, Michael Gaziano J, Geleijnse JM, Gigante B, Giles G, Guallar E, Gudnason V, Harris T, Harris WS, Helmer C, Hellenius ML, Hodge A, Hu FB, Jacques PF, Jansson JH, Kalsbeek A, Khaw KT, Koh WP, Laakso M, Leander K, Lin HJ, Lind L, Luben R, Luo J, McKnight B, Mursu J, Ninomiya T, Overvad K, Psaty BM, Rimm E, Schulze MB, Siscovick D, Skjelbo Nielsen M, Smith AV, Steffen BT, Steffen L, Sun Q, Sundström J, Tsai MY, Tunstall-Pedoe H, Uusitupa MIJ, van Dam RM, Veenstra J, Monique Verschuren WM, Wareham N, Willett W, Woodward M, Yuan JM, Micha R, Lemaitre RN, Mozaffarian D, Risérus U; Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Fatty Acids and Outcomes Research Consortium (FORCE). Biomarkers of Dietary Omega-6 Fatty Acids and Incident Cardiovascular Disease and Mortality. Circulation. 2019 May 21;139(21):2422-2436. doi: 10.1161/CIRCULATIONAHA.118.038908. 

Abstract. Background: Global dietary recommendations for and cardiovascular effects of linoleic acid, the major dietary omega-6 fatty acid, and its major metabolite, arachidonic acid, remain controversial. To address this uncertainty and inform international recommendations, we evaluated how in vivo circulating and tissue levels of linoleic acid (LA) and arachidonic acid (AA) relate to incident cardiovascular disease (CVD) across multiple international studies.....Conclusions: In pooled global analyses, higher in vivo circulating and tissue levels of LA and possibly AA were associated with lower risk of major cardiovascular events. These results support a favorable role for LA in CVD prevention.

Brigham EP, Woo H, McCormack M, Rice J, Koehler K, Vulcain T, Wu T, Koch A, Sharma S, Kolahdooz F, Bose S, Hanson C, Romero K, Diette G, Hansel NN. Omega-3 and Omega-6 Intake Modifies Asthma Severity and Response to Indoor Air Pollution in Children. Am J Respir Crit Care Med. 2019 Jun 15;199(12):1478-1486. doi: 10.1164/rccm.201808-1474OC. 

Abstract. Rationale: Higher indoor particulate matter (PM) concentrations are linked with increased asthma morbidity. Dietary intake of fatty acids, also linked with asthma outcomes, may influence this relationship. Objectives: To determine the relationship between omega-3 and omega-6 fatty acid intake and pediatric asthma morbidity, and the association between fatty acid intake and strength of indoor, PM-related asthma symptoms, albuterol use, and systemic inflammation. Methods: Analyses included 135 children with asthma enrolled in the AsthmaDIET Study. At baseline, 3 months, and 6 months, data included: week-long average home indoor concentration of PM ≤2.5 μm in aerodynamic diameter and PM ≤10 μm in aerodynamic diameter, dietary intake of omega-3 and omega-6 fatty acids, daily symptoms, and peripheral blood leukocytes. Asthma severity and lung function were assessed at baseline. Multivariable regression models, adjusted for known confounders, were used to determine associations between each fatty acid and outcomes of interest, with interaction terms (fatty acids × PM) in longitudinal analyses. Measurements and Main Results: Higher omega-6 intake associated with increased odds of increased asthma severity (P = 0.02), and lower FEV1/FVC ratio (P = 0.01). Higher omega-3 intake associated with reduced effect of indoor PM ≤2.5 μm in aerodynamic diameter on symptoms (P < 0.01), whereas higher omega-6 intake associated with amplified effect of indoor PM ≤2.5 μm in aerodynamic diameter on symptoms and circulating neutrophil percentage (P < 0.01). Conclusions: Omega-3 and omega-6 intake are associated with pediatric asthma morbidity and may modify the asthmatic response to indoor PM.

Christensen JJ, Bakke SS, Ulven SM, Retterstøl K, Henriksen T, Bollerslev J, Espevik T, Aukrust P, Halvorsen B, Holven KB. Serum Omega-6 Fatty Acids and Immunology-Related Gene Expression in Peripheral Blood Mononuclear Cells: A Cross-Sectional Analysis in Healthy Children. Mol Nutr Food Res. 2019 Apr;63(7):e1800990. doi: 10.1002/mnfr.201800990. Epub 2019 Feb 11. PMID: 30702198.

DiNicolantonio JJ, O'Keefe JH. Importance of maintaining a low omega-6/omega-3 ratio for reducing inflammation. Open Heart. 2018 Nov 26;5(2):e000946. doi: 10.1136/openhrt-2018-000946. PMID: 30564378; PMCID: PMC6269634.

 Sanders TAB. Omega-6 Fatty Acids and Cardiovascular Disease. Circulation. 2019 May 21;139(21):2437-2439. doi: 10.1161/CIRCULATIONAHA.119.040331. PMID: 31107617.