Spirulina platensis cell walls are composed of peptidoglycan (murein), which is a type of polysaccharide that is typically found in bacterial cell walls. Peptidoglycan is not digestible by humans.
In fact, research has shown that the peptidoglycan present in Spirulina platensis cell walls can be resistant to enzymatic digestion and may even inhibit the activity of certain digestive enzymes (Source: “Cell Wall Composition and Ultrastructure of Spirulina platensis” by Kumar et al., 2013).
This means that, unlike some other types of algae, Spirulina platensis cell walls are not likely to be digested by humans. Instead, they may pass through the digestive system relatively intact.
