Organic spirulina powder — Arthrospira platensis, a blue-green microalga grown in fresh water and dried into a fine, dark green powder with a distinctly marine, savoury taste. 125 g.
The most important thing on this page: spirulina is not a vitamin B12 source
This is the single most consequential misunderstanding in the whole plant-food aisle, and it matters most to exactly the people who buy spirulina.
Spirulina contains a large amount of something that looks like B12 in a laboratory assay. But the great majority of it is pseudocobalamin — an analogue that human beings cannot use. Worse, pseudocobalamin can register on some B12 tests and can compete with real B12 at the point of absorption, so relying on spirulina may leave you both deficient and falsely reassured.
If you are vegan or vegetarian, you need a genuine B12 supplement or reliably fortified foods. B12 deficiency causes irreversible neurological damage if it goes on long enough, and it develops slowly and quietly. Please do not use spirulina for this. Ask us and we will show you what actually works.
The protein figure, honestly scaled
Spirulina is genuinely around 60 to 70 per cent protein by dry weight, and that is a remarkable number for any organism. But the relevant figure is per serving: a typical 5 g spoonful gives roughly 3 grams of protein — about the same as half an egg white. Spirulina is a nutrient-dense addition to a diet. It is not a protein source, and the headline percentage quietly implies otherwise.
What it does bring at that dose is chlorophyll, phycocyanin (the blue pigment that gives it its name), iron and B vitamins other than B12. Check the pack for the amounts — the nutrition panel is what determines whether any nutrient claim actually applies.
What can and cannot be claimed for spirulina
Spirulina is widely sold as "supporting energy levels" and "helping reduce fatigue". That claim does not appear here. There is no authorised EU health claim for spirulina. Some nutrients it contains do have authorised claims — iron contributes to the reduction of tiredness and fatigue — but only where the product supplies enough per portion to qualify, and that is a matter for the nutrition panel, not for a description.
Who should not take it
-
Anyone with phenylketonuria (PKU). Spirulina contains phenylalanine.
-
Anyone with an autoimmune condition or taking immunosuppressants — ask your doctor first. Spirulina has been reported to stimulate immune activity, which is the last thing wanted in that situation.
-
Anyone with gout or a history of kidney stones should be cautious at high doses — algae are high in nucleic acids, which raise uric acid.
- In pregnancy and breastfeeding, and for children, ask a doctor or pharmacist first.
On quality — and this is a real issue, not a scare. Spirulina grown in uncontrolled open water can be contaminated with microcystins, liver toxins produced by other blue-green algae that share its habitat, and with heavy metals. This is a genuine reason to buy certified organic spirulina from a producer that tests its batches, and to be wary of the cheapest product on any shelf.
How to use it
Start with half a teaspoon and work up — both because it is strong and because a large first dose can unsettle the digestion. It tastes marine and savoury, so it hides better in savoury food than in sweet: a smoothie with banana and cocoa, a green juice, guacamole, hummus, a salad dressing, or stirred into soup off the heat.
Do not cook it. Heat degrades the pigments and the B vitamins you are paying for. Add it at the end.
Store airtight, cool and dark — light and air fade the colour. A food supplement is not a substitute for a varied and balanced diet or a healthy lifestyle.