When shopping for mushroom supplements, you will often see terms like 'full spectrum' or 'mycelium on grain.' But what do these actually mean, and why should you care?What is Mycelium?Mycelium is the vegetative, root-like structure of the mushroom. It grows underground or within a substrate (like oats or rice). While it does contain some beneficial compounds, it is often mostly starch if grown on grain.What is the Fruiting Body?The fruiting body is the actual mushroom cap and stem that sprouts above ground. This is where the highest concentration of active medicinal compounds—like beta-glucans and triterpenes—is found.Why It MattersMany cheaper supplements use mycelium grown on grain because it is faster and cheaper to produce. However, these products often lack the potent medicinal profile of the fruiting body. Always look for supplements that explicitly state they use '100% fruiting body' extracts to ensure you are getting the maximum therapeutic benefits.