<p>Packed with anti-hyperglycaemic, antioxidant and anti-microbial property, one of the most widely used spices is cinnamon, which <a name="_Int_4RNfnmun">is derived</a> from the inner bark of&nbsp;<em>Cinnamomum</em>&nbsp;species. This article evaluates the trajectory of research on Cinnamomum to date. The four main commercial species of <em>Cinnamomum</em> differs and flavour, intensity, colour, texture, and aroma. The four primary commercial varieties are&nbsp;<em>Cinnamomum verum </em>(Ceylon/True cinnamon),&nbsp;<em>C</em>. <em>cassia</em>&nbsp;(Chinese cinnamon),&nbsp;<em>C. burmannii</em>&nbsp;(Indonesian/Padang cinnamon), and&nbsp;<em>C. loureiroi </em>(Vietnamese/Saigon cinnamon). The literature reveals that while all four species possess significant therapeutic potential, their phytochemical profiles and safety margins differ greatly. <em>C. verum</em> is with lowest coumarin content. In contrast, <em>C. cassia,&nbsp;C. burmannii</em> and&nbsp;<em>C. loureiroi </em>contain significantly higher levels of coumarin, a known hepatotoxic compound, with&nbsp;C<em>. loureiroi&nbsp;</em>often exhibiting the highest concentrations. Beyond analysing solvent efficiency, this review also highlights the experimental approaches in cinnamon research, comparative phytochemical profiles, analysis of its comparative phytochemistry and therapeutic potential of Cinnamon-associated endophytic fungi. Whereas preclinical evidence is robust, the review highlights bottlenecks in large-scale human clinical trials for most varieties beyond&nbsp;<em>C. verum&nbsp;</em>and<em>&nbsp;C. cassia.</em></p>