Huu-Cuong Nguyen

Microalgae and cyanobacteria are investigated for compounds that may relate to obesity and metabolic phenotypes, yet the evidence base remains scattered and inconsistently reported. We conducted a PRISMA-ScR scoping review of PubMed, Europe PMC, and OpenAlex and mapped eligible full-text studies to a controlled vocabulary covering intervention concepts, mechanistic pathway nodes, and obesity-related outcome domains. Of 2651 reports sought for full text, 936/2651 (35.3%) were not retrieved; therefore, evidence maps should be interpreted as conditioned on full-text accessibility. We included 836 studies and summarized study density (counts only) by population/model tier, mechanistic reporting depth, chemical class, and safety/toxin flags. The literature is concentrated in animal models (485 studies) and human studies (292), with fewer in vitro/ex vivo reports (59). Mechanistic reporting was often limited: 582 studies did not provide extractable mechanistic endpoints, whereas 254 reported biomarker or pathway “anchors”. Across intervention concepts, lipid/PUFA, carotenoids, phycobiliproteins, and polysaccharides were most common; within the anchored subset, inflammation (NF-κB), AMPK signaling, adipogenesis (PPARγ-related), and lipogenesis were the most frequently mapped nodes. Together, this evidence map clarifies where mechanistic anchoring and safety documentation are sparse and provides a clear starting point for downstream evaluation.