Beyond Beauty: Microalgae and Cyanobacteria as Next-Generation Platforms for Functional Dermocosmetics, Cutaneous Delivery, and Skin Health

Microalgae and cyanobacteria are valuable sources of bioactive ingredients and innovative biological systems for skin applications. Their metabolites include exopolysaccharides (EPS), mycosporine-like amino acids (MAAs), carotenoids, phycobiliproteins, peptides and lipopeptides, polyunsaturated lipids, chlorophyll derivatives, and distinctive secondary metabolites such as scytonemin. Cyanobacteria additionally provide defined molecular candidates, including sacran, C-phycocyanin, MAAs, scytonemin-related compounds, and specialized peptide scaffolds. These compounds may support hydration and barrier function, photoprotection, control of oxidative stress and inflammation, pigmentation, antimicrobial and antibiofilm activity, extracellular-matrix preservation, and wound repair. This review examines major bioactive families, their sources and mechanisms, with particular emphasis on the strength of evidence supporting skin applications. Recent developments from 2024 to 2026 are highlighted, including microalgal extracellular vesicles (nanoalgosomes), photoactivated antimicrobial systems, photosynthetic hydrogels and microneedle patches, green extraction and biorefinery strategies, reconstructed human skin and skin-on-chip models, and artificial-intelligence-assisted formulation. Most reported effects remain supported mainly by biochemical, cellular, or preclinical evidence, whereas human validation is still limited. Translation will, therefore, depend on rigorous chemical standardization, effective cutaneous delivery, demonstrated stability and safety, scalable manufacturing, and validation in human-relevant models. Microalgae and cyanobacteria thus extend beyond conventional natural extracts toward next-generation dermocosmetic and cutaneous-delivery platforms.