The stearic acid in borage oil can help with moisture retention, flexibility of the skin, and skin repair. The oleic acid offers moisturizing, cell regenerating, and softening to our skin. And the linoleic acid will help restore barrier function of our skin, and acts as an anti-inflammatory that can soothe dry skin and itchiness. GLA helps with inflamed skin, and helps restore barrier function faster than linoleic acid.
Studies have shown that 20% borage oil can help with reducing redness, and animal studies have shown borage oil is more effective than evening primrose oil in reversing epidermal hyperproliferation and increasing ceramide synthesis in guinea pigs. (Epidermal hyperproliferation is when our skin cells generate too quickly!) Unlike evening primrose oil, borage has not been shown to be effective for eczema.
Borage oil contains a few other fatty acids with 4% gadoleic acid (C20:1), 2% erucic acid (C22:1), and 2% nervonic acid (C24:1).
The main polyphenolic found in borage oil is ferulic acid (which you might remember from rice bran oil), which makes up about 50% of the total phenolic content. Ferulic acid is a very effective anti-oxidant, more powerful than Vitamin E, that can prevent skin aging, reducing age spots, and helps repair light and radiation induced damage. It penetrates skin to soften and moisturize, soothes wind chapped and sun burned skin, and reduces itching and inflammation. The tannins found in borage oil make it a more astringent oil than something like sunflower oil, so borage oil will feel a bit drier on our skin.
Borage oil contains about 400 ppm tocopherols, which, combined with the anti-oxidant ferulic acid gives borage oil a shelf life of about 6 months. You can increase this time by adding Vitamin E or chelating ingredients to your products.
Borage oil makes a great addition to your facial moisturizers or lotions intended for the winter months to help with dry, chapped, or inflamed skin. You can add it to a facial serum (again, this is coming up) or use it in something like an after bath oil spray. Use at up to 20% - the only reason we don't use it at higher levels is due to the cost!
Have fun formulating!