Black currant seed oil contains gamma-linolenic acid (GLA), a fatty acid that has multiple physiological roles. Studies have shown that GLA promotes healthy prostaglandin E1 (PGE1) production. Researchers at the University of Massachusetts medical school reported that GLA helps support healthy cytokine activity, a mechanism that may help to support joint comfort. Furthermore, a randomized, double-blind, placebo-controlled trial reported statistically significant support of joint health in subjects supplementing with GLA. Another randomized, double-blind, placebo-controlled trial performed at the Jean Mayer USDA Human Nutrition Research Center on Aging reported that black currant seed oil supplementation provided immune support in elderly subjects. Black currant seed oil has also been shown to potentially support premenstrual comfort.