Spirulina is one particular kind of blue-green algae with a centuries long history of safe human consumption. It is well known to be safe and nutritious. Hundreds of published scientific studies over the past thirty years have documented no toxicity.
Wild species grow in lakes and waterways, consuming whatever nutrients are in the water.
Some species of cyanobacteria are toxic just like mushrooms and some land plants. Most kinds of microcystis, anabaena and aphanizomenon flos-aquae are toxic. Wild blue-green algae has not been subject to spirulina's long safety testing. Companies that harvest wild species of blue-green algae from natural lakes cannot have the same degree of control as growing spirulina at Earthrise Nutritionals' farm. Harvesting wild algae presents a far greater risk of contamination by cyanobacterial toxins.