You open two spirulina product pages: one powder is deep green, the other bright blue. Is the blue one a different plant? Has something been added? Here’s the main difference: green powder contains whole dried spirulina. Blue powder is an extract that separates out its blue pigment, phycocyanin.

The green powder already contains blue pigment

Spirulina contains a mix of pigments. Chlorophyll contributes green, while phycocyanin is a blue pigment attached to protein. Phycocyanin helps the organism collect light for photosynthesis. There are also carotenoid pigments in the mix.

So green spirulina does not need to “turn blue.” The blue component is already there, alongside other pigments and the rest of the biomass. In whole dried powder, you see the combined appearance rather than an isolated blue ingredient.

Researchers have separated chlorophyll and carotenoids from phycobiliproteins in an experimental extraction study. Another study of phycocyanin extraction specifically examined limiting the carryover of green chlorophyll. That helps explain why separating the pigment fraction changes the color.

Blue spirulina is an extract, not the whole powder in a new shade

Extraction separates the desired blue fraction from other parts of the starting material. Think of choosing one part of a mixture, rather than simply grinding the same ingredient more finely. Different extraction and processing methods can produce different results.

That matters when shopping. A spoonful of blue extract is not nutritionally interchangeable with a spoonful of whole green spirulina. Compare the ingredient list and nutrition information for each product instead of carrying the green powder’s numbers over to the blue one. Neither the word “blue” nor a vivid photograph tells you the full composition.

Choose for the job you want it to do

If your main aim is adding a blue color to food, look at a phycocyanin product such as AimGrow Blue Spirulina, 50g. If you want whole green spirulina powder, look at the separately listed AimGrow Spirulina Powder, 454g. These are different ingredient forms, not two pack sizes of the same powder.

Do not use color depth as a health score. Darker powder or a more intensely colored spoonful does not show that a product will be more effective. For a food-color project, the useful question is whether it gives the result you want in that particular food.

Try the color in a small portion first

Before coloring a whole bowl, set aside a little of the food you actually plan to use. Following the pack’s directions, mix in a small amount and check it in ordinary daylight. A white base and an already green or brown base can give very different-looking results.

If you compare blue and green powder, use separate small portions and clean spoons. You are checking appearance, mixing, and your own taste preference—not trying to match their nutrition by eye. Once you like the result, make a note of what you used before tackling the larger batch.