While MRL Ltd. Grifola frondosa is not an extract of Grifola frondosa, the powder does contain both mycelium and primordia (young fruit body) cultivated into a biomass that is grown on a sterilised (autoclaved) substrate. This cultivation process ensures the powder is free from contamination by other fungi and that pesticides and heavy metals are absent. The cultivation system is proprietary, allowing for standardised production of Grifola frondosa. The powder biomass is then sealed in plastic containers.