Phycocyanin is an intracellular protein, which is an extract from Spirulina. It is separated by breaking the spirulina cell sediment. Because it appears blue after extraction, it is called phycocyanin. It is a natural, edible and harmless pigment. It is the only azure blue pigment allowed by the US FDA, and neither the US FDA nor the EU restricts its usage, so you can eat it with confidence.