Spirulina and chlorella
What spirulina and chlorella are, how these algae differ, what "broken cell wall" means and how to read the label.
This substance has no health claim authorised in the European Union. So we describe what it is and how it is taken, but do not say what it does in the body.
What they are
Spirulina is a blue-green microalga (strictly, the cyanobacterium Arthrospira), gathered and eaten for centuries around lakes in Central Africa and Mexico. Chlorella is a single-celled green freshwater alga. Both are grown in ponds, dried and sold as powder and tablets.
Dried spirulina is rich in protein — about 60 % by weight — but a daily serving of a few grams gives only a couple of grams of protein. Spirulina and chlorella have no authorised health claims in the European Union, so we describe what is in them, not what they do.
How to read the label
Chlorella has a tough cell wall, so it is sold "broken cell wall" — a processing technique. Look for organic certification and testing for heavy metals and microcystins: algae take up whatever is in the water. Greens blends combine algae with powdered herbs, sprouts and vegetables.
How they are taken, and precautions
Tablets and powder are taken as the pack directs; the powder goes into smoothies and juices. Start with a smaller serving. Spirulina is not for people with phenylketonuria; people with autoimmune conditions, pregnant or breastfeeding women and anyone on blood thinners (chlorella contains vitamin K) should ask a doctor first.
Frequently asked questions
How is spirulina different from chlorella?
Spirulina is a soft-walled blue-green cyanobacterium, chlorella a green alga with a tough cell wall. That is why chlorella is sold broken-cell-wall.
Is spirulina high in protein?
Dry spirulina is about 60 % protein, but a serving is usually 3–5 g, i.e. 2–3 g of protein.
What should I look for when choosing?
Purity testing (heavy metals, microcystins), origin and the price of a daily serving.
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