Policosanol is a promising compound that can be used in various industries. In the pharmaceutical industry, policosanol and, specifically, triacontanol, octacosanol, and hexacosanol have presented biological activity against several diseases, especially those related to inflammation and hypercholesterolaemia. On the other hand, triacontanol is used as a growth promoter in a wide variety of plants and crops of economic importance, even in microalgal culture, in either its pure form or in policosanol extracts. In this review, the most relevant references to the bioactivities of policosanol in plants and animal cells are collected to compare the different mechanisms of action. Analyzing this in detail allows us to ask new research questions. The PubMed and Redalyc database were used for article search under the following keys terms: policosanol, inflammatory mechanisms, triacontanol, cellular absorption, photosynthesis and photoinhibition. Policosanol interferes with the progression of the NF-κB and MAPK signaling pathway involved in the inflammation process. The cholesterol-lowering effect of policosanol is due to the inhibition of cholesterol synthesis in the liver, through the indirect inactivation of HMG-CoA reductase. Triacontanol improves the growth and the biochemical and physiological parameters of plants and the response to stress conditions that is related mainly to photosynthetic activity. Interestingly, octacosanol demonstrates an inhibitory activity on the effect of triacontanol in plants, a response not reported in human cells, as well as other differential aspects of the mechanisms of action in the cells of plants and animals that are interesting to analyze.