Lions Mane

This nontoxic medicinal and culinary mushroom is believed to stimulate nerve growth. It also may improve mild cognitive impairment. A Japanese study published in 2009 found that test scores of study participants who took Lions Mane in tablet form improved as over the course of the 16 weeks they took the pills but declined afterwards. The researchers concluded that Lions Mane mushrooms are effective in improving mild cognitive impairment.