Phytoplankton FAQ’s
The questions buyers ask us most, answered plainly. Where a question touches on health, we have stuck to what the nutrition genuinely supports and left the disease claims out. A food supplement is not a medicine, and if you have a health condition or take medication, check with your GP or pharmacist first.
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What does marine phytoplankton taste like?
Green and faintly of the sea, in the same family as spirulina or chlorella but milder than either. Most people get on fine with a half-teaspoon in water. If it is not for you, stir it into juice or a smoothie and it more or less vanishes. I would not let the taste put you off before you have tried that.
Why does it cost more than other supplements?
Because it is slow and fiddly to make. Selecting a strain, growing it under controlled conditions, then drying, milling and packing it gently to protect the omega-3s all add cost, and the batches stay small. None of that makes it magic. It does, though, explain the gap between this and a mass-produced powder. Whether the gap is worth it depends on what you actually want from it.
Is marine phytoplankton vegan?
Yes, fully plant-based. The word plankton trips people up, because it covers a huge range of drifting organisms, some of them animals. Phytoplankton is the plant side of that group: microscopic single-celled algae that feed on sunlight. The powder is the dried algae and nothing else, so there is no hidden animal ingredient to worry about.
How is it grown, and is it GMO?
Ours is grown in a closed commercial bioreactor in Germany, using purified water rather than open sea, which keeps it well away from ocean contaminants. It is not genetically modified. The strain comes from ordinary selective breeding, the same patient process used for crops, not from genetic engineering, which is a distinction worth holding onto when a label stays vague about it.
Is it the same as spirulina?
No. Marine phytoplankton is a saltwater microalga, while spirulina is a freshwater cyanobacterium. Their nutrient profiles differ, so you cannot simply swap one for the other and expect the same thing. We set out the differences in full in our guide on phytoplankton and spirulina if you want the detail.
How do you take it, and how much?
Most people take about 1g, a level half-teaspoon, once a day, in water, juice or a smoothie. There is no need to work up to big doses, and more is not better. A steady small amount is the sensible way to use it. For more detail, see our guide on how to take marine phytoplankton.
How should I store it, and does it expire?
It does expire, so check the best-before date and buy what you will get through rather than stockpiling, because the omega-3s degrade slowly over time. Keep it somewhere cool and dark. Once it is open, the supplier recommends keeping it in the fridge, and that is the habit I would get into to protect the part you are paying for.
Does marine phytoplankton contain iodine?
Only negligible traces. Iodine is concentrated in seaweeds and macroalgae such as kombu, not in marine microalgae like phytoplankton. Our production water is filtered and purified and no iodine is added, so there is none to speak of in the finished powder. If iodine is specifically what you are after, this is not the supplement to reach for.
What is marine phytoplankton good for?
Treat it as a nutrient-dense food rather than a remedy. Its real draws are being a rare plant source of EPA omega-3 and a complete protein, in cells that are easy to absorb. Where a serving provides a meaningful amount of iron, EFSA recognises that iron contributes to normal energy-yielding metabolism, the reduction of tiredness and immune function, so check the panel on your pack.
What it is not is a treatment for any disease, and we will not pretend otherwise. For the honest, full version, see our guide to the benefits of marine phytoplankton and what is actually in it.
How do I choose a good one?
I would start with three things: a named strain, a nutritional panel you can read, and a producer who tests what they sell. Steer clear of powders bulked out with fillers. One thing worth knowing before you compare prices: cultivation for human food is still a small industry, so much of what is sold comes from a few facilities under different labels. Our own product is in the shop.
How we have assessed this
The iron functions named here are EFSA-authorised health claims under Commission Regulation (EU) No 432/2012, and they apply only where a serving provides a meaningful amount, so check your pack. Statements about what phytoplankton is and contains are ingredient-level facts from published analyses, not figures for one branded tub. You can read more about how we work in our testing and sourcing policy.
This page makes no claim to diagnose, treat, prevent or cure any disease. It is general information, not medical advice, and you can read our method in our editorial policy. Last reviewed: June 2026.
Cara Hayes is an experienced natural health practitioner with a Masters in Clinical Nutrition & Dietetics from the University of Sydney. She has been writing for Plankton for Health since 2019 and contributes widely to many well-known health publications.