The highest quality and highest potency evening primrose oil capsule available. More than twice the potency of many other brands which contain only 500 mg. Because it is more potent, one or two capsules a day are all you need. The evening primrose oil in this product is extracted without hexane or other chemical solvents. It uses only the cold process, "expellor-press" method of extraction, which is simply squeezing the oil out of the seed without heat. Packaged in a glass bottle for maximum stability, quality and freshness. Twinlab Mega Primrose Oil 1300 capsules are, therefore, more convenient and economical.