The fruiting body is the visible, reproductive part of the mushroom—what you would recognize as a Lion's Mane mushroom growing on a log. Mycelium is the root-like network of fungal threads, often cultivated on a grain substrate. In food and herbal traditions, the fruiting body has historically been the part consumed and valued. The product description notes it uses an extract from the fruiting body, standardized for polysaccharides. This choice typically indicates the manufacturer is sourcing and concentrating the part of the mushroom traditionally associated with its use. Some consumers and traditions prefer fruiting body extracts because they represent the whole, traditionally used organism, whereas mycelium-on-grain products can include a significant portion of the grain substrate. This product's composition is a straightforward, single-ingredient fruiting body extract, which may be preferred by those seeking a simple, traditional source.