A polysaccharide found in the goji berry has been found to be a powerful secretagogue (a substance that stimulates the secretion of rejuvenative human growth hormone by the pituitary gland). Goji berries have been traditionally regarded as a longevity, strength-building, and sexual potency food of the highest order. In several study groups with elderly people the berry was given once a day for 3 weeks, many beneficial results were experienced and 67% of the patients T cell transformation functions tripled and the activity of the patients white cell interleukin-2 doubled.