SummaryIn recent years, Cordyceps militaris has garnered increased attention in both scientific research and popular culture, exemplified by references in the entertainment industry, such as ‘The Last Of Us’. This study aims to investigate the qualitative and quantitative composition of bioactive compounds (such as cordycepin, ergothioneine, L‐phenylalanine, lovastatin, sterols, indole and phenolic compounds) in various samples. These samples encompass commercially available dietary supplements (in the form of capsules or powder), featuring standardised extracts or non‐standardised C. militaris material. Additionally, fruiting bodies cultivated in Poland and China were examined. The bioactive compounds were subsequently analysed after extraction into artificial digestive juices. Each sample underwent extraction, evaporation and dissolution in methanol, followed by qualitative and quantitative analyses using RP‐HPLC (with UV and DAD detectors) for the determination of bioactive compounds. The results of this analysis revealed that extracts with cordycepin contents of 7% and 1% exhibited the highest cordycepin concentrations, as well as significant ergothioneine levels (4405 and 928 mg/100 g d.w. and 234 and 77.6 mg/100 g d.w. respectively). However, on analysis of simulated digestive juices, it became evident that the fruiting bodies of C. militaris are superior sources of bioactive compounds. Consequently, this study underscores the efficacy of unprocessed material, such as fruiting bodies, as the preferred form of supplementation for potential consumers of C. militaris.