Microalgae are unicellular photosynthetic microorganisms that are commonly found in saline or freshwater environments. Over the years, microalgae represent promising sources of sustainable bioactivities with past literatures reflecting a growing interest in algae-based dietary supplements in the form of whole biomass. Notably, the bioactive molecules that can be identified and extracted in microalgae have scientifically proven to contain therapeutic properties which can be beneficial to human health. With the increasing occurrence of global health threats such as antimicrobial resistance and cancer, this has resulted in considerable attention for microalgae study especially in the medicinal field. Although studies have proved the therapeutic potentials of high-value bioproducts in microalgae, however, there is still room to understand their potential therapeutic properties on humans’ health, discovering novel microalgae-derived bioactive compounds, as well as translating the lab-based evidence to clinical trial studies. This review will focus on accessing the biochemical compositions of commercialised microalgae species from 2007 to 2020, and the activity of their biologically active molecules in eliciting selected therapeutic potentials which are anti-oxidative, anti-inflammatory, anti-microbial and anti-cancer properties. This review article will also be looking at the research gaps in addition to the above four major selected therapeutic potentials, and future prospective. Display omitted