Sourcing GLA: evening primrose oil vs borage


The beneficial effects of borage oil and evening primrose oil (EPO) have been reported in a number of inflammatory-mediated conditions and these benefits are generally associated with the omega-6 polyunsaturated fatty acid gamma-linolenic acid (GLA) content of these oils. GLA is converted to dihomo-gamma-linolenic acid (DGLA), which is the precursor to anti-inflammatory prostaglandins and anti-thrombotic leukotrienes.

Often found as an addition to fish oil supplements that aim to deliver both omega-3 and omega-6 to provide balance, it would seem at first glance that borage oil is the ideal plant oil for use in nutraceuticals targeting inflammatory conditions. Why, then, when borage oil is cheaper and contains twice as much GLA as EPO do we at Igennus choose to use EPO in preference to borage oil to complement our pure EPA products?

Evening primrose oil is safer and doesn’t need to be refined

Unrefined borage oil contains traces of naturally occurring toxins called pyrrolizidine alkaloids (PAs).[1] These compounds have been shown to be both hepatotoxic and carcinogenic [2] and are present within the seeds and leaves of the plant to deter animals from consuming them. Refining borage oil is therefore a requirement to ensure these compounds are at levels safe for human consumption; however, whilst the refining process is a necessity, it also strips the oil of a number of beneficial compounds, including vitamin E, carotene, phytosterols, sterols, lecithin, polyphenolic antioxidants, as well as others. The health benefits attributed to borage oil therefore rely solely on its GLA component.

The trace level of PAs present within the leaves and seeds of EPO fall significantly below levels required to exert any potentially toxic effects, making unrefined EPO a safe and therefore superior choice over borage oil. Whilst some manufacturers do choose to use refined EPO in their ingredients, we choose to use organic cold-pressed non-raffinated EPO which retains all oil-soluble compounds, thus complementing and acting in synergy with its GLA content to deliver additional beneficial biological activities – supporting immune and inflammatory regulating pathways and helping to protect the body from damage arising from oxidative stress.

Cold-pressed evening primrose oil is rich in beneficial polyphenols

The long-chain fatty alcohols (LCFAs) hexacosanol, tetracosanol, docosanol and octocosanol present within organic, cold-pressed, non-raffinated EPO possess anti-inflammatory activity and have been shown to reduce the generation of mediators involved in the inflammatory response.[3] Unrefined EPO is also rich in sterols and, in addition to the cholesterol-lowering effects and the anti-cancer properties attributed to sterols, specific phytosterols present in EPO have been shown to exhibit antibacterial and antifungal activities, as well as numerous anti-inflammatory effects, including the reduced production of pro-inflammatory products derived from the inflammatory omega-6 fatty acid arachidonic acid (AA).[4] Triterpenes, also unique to unrefined EPO, possess free radical scavenging and cyclooxygenase inhibitory properties, thus further reducing the conversion of AA to pro-inflammatory mediators.[5]


Whilst borage and EPO are usually primarily considered as beneficial for their GLA content, it is the additional bioactive minor compounds that are present in unrefined EPO that supports its use in managing inflammatory processes. In its organic, cold-pressed, non-raffinated state (as outlined above, this is not safely possible with borage oil) evening primrose oil therefore offers health benefits that surpass ordinary refined preparations of both EPO and borage.[6]


  1. Vacillotto G, Favretto D, Seraglia R, Pagiotti R, Traldi P, Mattoli L: A rapid and highly specific method to evaluate the presence of pyrrolizidine alkaloids in Borago officinalis seed oil. Journal of mass spectrometry : JMS 2013, 48:1078-1082.
  2. Li N, Xia Q, Ruan J, Fu PP, Lin G: Hepatotoxicity and tumorigenicity induced by metabolic activation of pyrrolizidine alkaloids in herbs. Current drug metabolism 2011, 12:823-834.
  3. Montserrat-de la Paz S, Garcia-Gimenez MD, Angel-Martin M, Perez-Camino MC, Fernandez Arche A: Long-chain fatty alcohols from evening primrose oil inhibit the inflammatory response in murine peritoneal macrophages. Journal of ethnopharmacology 2013.
  4. Montserrat-de la Paz S, Fernandez-Arche A, Angel-Martin M, Garcia-Gimenez MD: The sterols isolated from Evening Primrose oil modulate the release of proinflammatory mediators. Phytomedicine : international journal of phytotherapy and phytopharmacology 2012, 19:1072-1076.
  5. Knorr R, Hamburger M: Quantitative analysis of anti-inflammatory and radical scavenging triterpenoid esters in evening primrose oil. Journal of agricultural and food chemistry 2004, 52:3319-3324.
  6. Puri BK: The clinical advantages of cold-pressed non-raffinated evening primrose oil over refined preparations. Medical hypotheses 2004, 62:116-118.



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