Spirulina is the common name for two species of cyanobacteria — Arthrospira platensis and Arthrospira maxima— that grow naturally in warm, alkaline lakes. Despite often being called “blue-green algae”, spirulina is technically a bacterium, not a plant or an algae. That distinction matters when you read research papers, but for nutritional and culinary purposes the older name has stuck.
What makes it interesting is the combination of three things in a single, very small package: about 60–70% complete protein by dry weight, an unusual density of certain micronutrients (notably iron, B-vitamins, and a copper-bearing blue-green pigment called phycocyanin), and a long human history of safe use stretching from Aztec markets in 16th-century Mexico to Lake Chad communities today.
Where does it come from?
In the wild, spirulina blooms in mineral-rich saline lakes — Lake Texcoco in Mexico, Lake Chad in West Africa, Lake Klamath in Oregon, and shallow alkaline lakes across East Africa. These are not the kind of waters most algae can survive in: high pH, high carbonate, sometimes dangerously hot. That hostile habitat is part of why spirulina is so distinctive and so safe — almost nothing else grows there to compete with it or contaminate it.
Almost all commercial spirulina today is cultivated, not wild-harvested: grown in shallow paddle-wheel ponds (the Hawaii, Taiwan, and Inner Mongolia method), in closed photobioreactors (smaller European and Indian producers), or by small home-cultivators with a few hundred liters of glass tanks.
How is it made into the powder you buy?
The freshly harvested biomass is filtered, washed, then dried — usually by spray-drying (fast, but slightly lossy on heat-sensitive compounds), drum-drying (less common), or by gentler methods like vacuum-drying or low-temperature drying. The dried powder is then either packaged loose, compressed into tablets, or extruded into “flakes”.
Drying method is one of the few things that genuinely separates a $20 spirulina from a $60 spirulina — alongside the cleanliness of the source water and the rigor of the heavy-metal testing. We cover this in detail on the quality & purity page.
What does it actually taste like?
Honestly: it tastes the way a clean lake smells. Slightly grassy, slightly oceanic, mildly bitter. People expecting it to be neutral are usually disappointed; people expecting it to be unbearable are usually relieved. Mixing 1–3 grams into a fruit smoothie, a pesto, or a chocolate energy ball masks the flavour almost entirely.
The honest summary
Spirulina is one of the most nutrient-dense, well-studied, and well-tolerated whole foods that exists. It is also routinely oversold by the people who profit from it. The goal of the rest of this site is to help you tell the two apart — and to use it well once you decide it’s worth using.