Primary Supplemental Sources of Gamma Linolenic Acid
For those seeking reliable and concentrated forms of gamma linolenic acid (GLA), supplemental oils derived from specific plant seeds are the most effective option. These oils contain significantly higher percentages of GLA compared to most foods, making them the most common way to increase intake. The three most cited sources for GLA supplementation are borage oil, evening primrose oil, and black currant seed oil.
Borage Oil (Borago officinalis) Borage oil stands out as the richest and most potent supplemental source of GLA, with concentrations ranging from 17% to 25%. Extracted from the seeds of the star-shaped borage flower, this oil has a long history of use in herbal medicine. Beyond its high GLA content, borage oil is also known for its moisturizing and soothing properties, and is used in various topical skincare products. When choosing a borage oil supplement, it is important to select one that is certified free of toxic pyrrolizidine alkaloids (UPAs), which can be harmful to the liver if present in unpurified oil.
Evening Primrose Oil (Oenothera biennis) Evening primrose oil (EPO) is another well-established source of GLA, though it contains a lower concentration than borage oil, typically between 7% and 10%. EPO is derived from the seeds of the evening primrose plant, which has yellow flowers and is native to North America. Historically used for a variety of conditions, it is a popular supplement, particularly for women's health issues such as PMS symptoms and hormonal balance. Like other GLA sources, it is taken for its anti-inflammatory effects and potential skin benefits.
Black Currant Seed Oil (Ribes nigrum) Black currant seed oil is a lesser-known but still notable source of GLA, providing a concentration of approximately 15%. This oil is unique among GLA sources as it also contains a significant amount of omega-3 fatty acids, creating a more balanced fatty acid profile. This dual-omega content is sometimes preferred by those looking for both anti-inflammatory omega-6 and omega-3 support. The oil is expeller-pressed from the seeds of the black currant fruit and is available in softgel supplements.
Other Sources and Dietary Considerations While the primary sources of GLA are these concentrated seed oils, it is important to remember that the body can synthesize GLA from linoleic acid (LA), a more common omega-6 fatty acid found in many household cooking oils such as sunflower, safflower, and corn oil. The efficiency of this conversion, however, can be limited by factors such as age, poor diet, and certain medical conditions. This is often the reason some people turn to direct GLA supplementation. Echium seed oil is another botanical oil that offers a unique omega-3, -6, -9 fatty acid profile, including GLA, and is considered a vegan alternative to fish oil for boosting omega levels. Human breast milk also contains small amounts of GLA.
Comparison of Major Gamma Linolenic Acid Sources
| Source | Botanical Name | GLA Percentage | Other Noteworthy Fatty Acids | Considerations |
|---|---|---|---|---|
| Borage Oil | Borago officinalis | 17–25% | Also contains linoleic acid | Highest GLA concentration; ensure it is UPA-free |
| Evening Primrose Oil | Oenothera biennis | 7–10% | Also contains linoleic acid | Long-standing reputation for women's health; lower GLA content |
| Black Currant Seed Oil | Ribes nigrum | ~15% | Also contains alpha-linolenic acid (omega-3) and stearidonic acid | Offers a blend of both omega-6 and omega-3 fatty acids |
| Echium Seed Oil | Echium plantagineum | ~12% | Also contains alpha-linolenic acid (omega-3) and stearidonic acid | Vegan source of both omega-3 and omega-6 |
Choosing a High-Quality GLA Supplement
When selecting a GLA supplement, several factors are worth considering to ensure you are getting a safe and effective product. The method of extraction is important, with cold-pressed oils being preferred for preserving the oil's nutritional integrity. Purity is also paramount, especially for borage oil, which should be certified free of pyrrolizidine alkaloids (PAs). Additionally, checking for third-party testing can offer assurance that the supplement contains what the label claims and is free from contaminants. Ultimately, the best choice depends on individual needs, desired GLA concentration, and whether you want a supplement with additional fatty acids, like black currant seed oil or echium seed oil.
Conclusion
Gamma linolenic acid is an important omega-6 fatty acid primarily sourced from a few select plant seed oils, with borage oil offering the highest concentration. While the body can convert other omega-6s, direct supplementation from sources like borage, evening primrose, or black currant oil is a reliable way to ensure adequate intake, especially for individuals with compromised conversion abilities. When exploring options, it is recommended to consult a healthcare provider to determine the best source and dosage for your specific health needs.
