Gelidiella acerosa is a species of red alga that is used as a source of phycocolloids, primarily agar and carrageenan. According to a 2018 publication in the journal Cosmetics, these phycocolloids are water-soluble polysaccharides, mainly used to thicken aqueous solutions, to make gels of variable degrees of firmness, to produce water-soluble films, and to stabilize products.