Spirulina: composition, properties, dosage and contraindications

Spirulina: properties, composition and uses as a dietary supplement

Spirulina is the common name for the dried biomass of cyanobacteria (blue-green algae) of the genus Arthrospira, most often Arthrospira platensis. In practice, you will find it as a dietary supplement in powder or tablet form – mainly because of its concentrated nutrients (including protein, pigments and antioxidant compounds). However, it’s worth approaching the topic sensibly: it is a complement to the diet, not a “magic solution”.

Note: This article is for educational purposes only and does not replace the advice of a doctor or dietitian. If you have a chronic illness, take medication, are pregnant or breastfeeding, consult a specialist before starting supplementation.

What is spirulina and where does it come from?

In everyday language, people often talk about a “microalga”, but biologically it is a cyanobacterium (blue-green algae) capable of photosynthesis. Most often, “spirulina” in supplements is the biomass of Arthrospira platensis (sometimes you will also come across the species Arthrospira maxima). In older sources and in marketing you may also see the name Spirulina platensis – today considered historical.

Arthrospira platensis as a source of spirulina

Arthrospira platensis grows naturally in warm, alkaline water bodies and is usually cultivated commercially under controlled conditions. For the consumer, what matters is not so much the “exotic origin” as the quality of the process: control of the water, hygiene and testing of the final product.

In practice, you may come across terms such as Hawaiian spirulina or Asian spirulina – they indicate the region of production or origin, but are not an automatic guarantee of the “highest quality”. Whether a product is safe and valuable is determined primarily by quality standards and testing.

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What is spirulina made of? Spirulina composition and nutrients

What exactly spirulina consists of depends on the growing conditions and the drying method. However, it is usually described as a concentrate of ingredients such as:

• protein (often a high protein content in the dry matter),
• amino acids and other nutrients,
• natural pigments (including phycocyanin, chlorophyll, beta-carotene),
• fatty acids (including gamma-linolenic acid – GLA),
• selected vitamins and minerals (their amounts may differ between products).

Nutrients and “nutrient content” – what is worth knowing?

Product descriptions often feature the phrase “rich in nutrients”. It is true that spirulina contains many compounds, but two things are key:

• real serving size – supplements are usually used in portions measured in grams, so their contribution to the daily diet is typically an addition rather than a “base”,
• variability – the “nutrient content” differs between brands and batches.

If you care about specific numbers, check the nutritional information table. Sometimes you may also see test results and raw material parameters.

Protein: why is it mentioned so often?

One of the reasons for spirulina’s popularity is its high protein content in the dry matter. In everyday nutrition, it can be a convenient way to supplement your menu, especially if you care about diverse protein sources (e.g. in plant-based diets). At the same time, it’s worth remembering that a supplement will not replace a full, balanced meal.

Pseudovitamin B12 – important information for vegans and vegetarians

Marketing sometimes emphasizes that “spirulina also contains vitamin B12”. The problem is that in many products the dominant forms are inactive analogues (the so-called pseudovitamin B12), which are not considered a reliable source of B12 in the diet. If you follow a plant-based diet, do not base your B12 supplementation solely on such a product – it is better to use proven B12 supplements in line with a specialist’s recommendations.

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Properties and effects of spirulina – what does science say?

Online you will often see phrases such as “beneficial properties of spirulina” or “health-promoting properties”. It’s worth approaching them calmly: research on the effects of spirulina on the body is ongoing, and results depend, among other things, on the dose, duration of use and product quality. The firmest ground is the description of its composition and the potential of compounds such as pigments and antioxidants.

Antioxidants and pigments: phycocyanin, chlorophyll, beta-carotene

The most commonly mentioned in this category are:

• phycocyanin – a pigment described in laboratory studies as a compound with antioxidant properties,
• chlorophyll – a plant pigment often associated with a diet rich in green ingredients,
• beta-carotene – a compound classified as a carotenoid.

These types of antioxidants are also naturally present in many vegetables and fruits. A supplement can be an additional element, but a balanced diet remains the foundation.

Inflammation and “support” – careful language matters

Some scientific publications describe compounds from spirulina in the context of processes such as inflammation and oxidative stress. In practice, however, it is not worth translating this directly into promises that it “treats inflammation” in the medical sense. If you want real support for your body, a better base is your lifestyle: sleep, physical activity, diet and consultation with a doctor in case of specific problems.

Cholesterol levels – what can be said without overinterpretation?

Reviews of clinical trials have analysed whether supplementation may be associated with changes in markers such as cholesterol levels. The results can be promising, but they are not a ticket to self-treatment. If your lipid profile results are abnormal, the foundation is proper diagnostics, diet, activity and – if needed – treatment supervised by a doctor.

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Spirulina for weight loss – how to approach the topic sensibly?

The phrase spirulina for weight loss is very popular, but it’s worth demystifying it. Studies have evaluated the impact of supplementation on body weight and body composition – however, no supplement will replace the basics: an energy deficit, a sensible meal plan and physical activity.

If you want to use the product as part of your strategy, treat it more as:

• a dietary add-on that may make it easier to stick to your plan (e.g. thanks to ease of use),
• an ingredient that supports habits (e.g. fixed mealtimes, preparing a smoothie),
• a flavour alternative in the kitchen.

Weight loss is a process in which consistency matters most. If something sounds like a quick shortcut, it is usually marketing rather than a real strategy.

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Spirulina powder – use in the kitchen

Spirulina powder is chosen by people who like flexibility. You can add it to drinks and meals, controlling the amount “by the teaspoon”. Its flavour is distinctive (marine, plant-like), so it pairs well with fruit.

Healthy smoothie idea: banana + mango + yogurt/plant-based drink + a pinch of powder. It’s a simple way to add variety to your everyday diet.

Other ideas for using spirulina:

• as an addition to shakes and smoothies,
• homemade sauces and dips (e.g. yogurt-based),
• cream soups (added at the end, after removing from the heat),
• batter for pancakes or fritters – for the colour and “wow effect”.

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Spirulina tablets – convenience of use

Spirulina tablets are an option for people who don’t want the taste of the powder and prefer a simple routine. An additional advantage is easier control of the amount taken.

If you choose Spirulina platensis tablets, pay attention to:

• how many mg of Spirulina platensis there are in one tablet,
• what the manufacturer’s recommended daily serving is,
• whether the product has quality testing (e.g. heavy metals, microbiology).

In practice, “spirulina tablets” differ in weight. That’s why you should compare products not by the number of tablets, but by the actual serving size in grams and overall quality.

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Spirulina dosage – how to read the label and choose the right serving

Spirulina dosage is not “one size fits all”, because products have different concentrations and different recommendations. The safest practical approach looks like this:

• Follow the label – in particular, adjust the amount of nutrients so that it complements your diet; the label may also contain the recommended serving.
• Start with a smaller amount and observe your tolerance (especially if you have not used such supplements before).
• If you use Spirulina platensis tablets, calculate the dose in grams based on the information “mg Spirulina platensis per tablet”.

In product descriptions you may see repeated information about “several grams per day” – and indeed, in studies doses in the gram range are often used. However, in everyday supplementation the most important factors are tolerance, regular use and product quality.

It is best to fit taking spirulina into your daily routine (e.g. with a meal), so that it is simply convenient. If you experience stomach discomfort, take a break and consider consulting a healthcare professional.

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Spirulina quality – how to choose good quality and avoid contamination?

Spirulina quality is a key topic. Good-quality spirulina should come from controlled production. With supplements from aquatic raw materials, possible risks include contamination (e.g. cyanobacterial toxins, heavy metals, bacteria). A very good choice is definitely spirulina with organic certification.

What should you pay attention to if you want to choose good-quality spirulina?

• a transparent manufacturer and batch traceability,
• purity testing (heavy metals, microbiology),
• production standards and quality systems, e.g. PL-EKO-03 certificate, GMP certificate, ISO 22000 certificate, HACCP certificate (it’s worth looking for information about implementation and audits).

Organic spirulina and “natural spirulina” – how to understand these terms?

Organic spirulina or ecological spirulina means that the requirements of organic farming have been met (depending on the market and certification), but this does not remove the need to verify purity test results. The term “natural spirulina”, on the other hand, is often used as marketing – specific standards and documentation matter more than the wording itself.

Hawaiian spirulina vs Asian spirulina – what really matters?

“Origin” can be a hint, but it does not replace solid quality criteria. Instead of assuming that a given region automatically equals the highest quality, it is better to check the producer’s documentation, test results and credibility. This is the simplest way to choose a product that truly deserves to be called “good quality”.

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Contraindications to supplementation and precautions

Contraindications are always worth taking seriously – especially with products whose quality may vary. The most commonly mentioned are:

• phenylketonuria (PKU) – due to the presence of phenylalanine,
• a tendency to allergic reactions or hypersensitivity,
• use of medications and chronic diseases (in such cases it is better to discuss supplementation with a doctor),
• pregnancy and breastfeeding – require caution and consultation (due to limited data for many supplements and the risk of contamination).

Possible symptoms of intolerance may include digestive discomfort. If any worrying reactions occur, stop using spirulina and consult a specialist.

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Spirulina and chlorella – similarities, differences and combining

Spirulina and chlorella are often grouped together under the label of “green supplements”, but they are different organisms with different ingredient profiles. In practice, combining them is often a matter of preference (e.g. taste, form) and tolerance. If you plan to supplement both at the same time, start with small portions and observe how your body responds.

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FAQ: most frequently asked questions

What is spirulina?

It is the common name for the dried biomass of cyanobacteria of the genus Arthrospira, sold as food or as a dietary supplement (most often powder or tablets).

What does spirulina consist of?

It is most often described as having a high protein content, containing pigments (e.g. phycocyanin, chlorophyll), carotenoids (e.g. beta-carotene), as well as vitamins and minerals. The exact composition depends on the product and production quality.

Spirulina powder – how to start?

The simplest way: add a small amount to a smoothie or yogurt. Start with a small serving, check your tolerance and only then consider regular use.

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Summary: using spirulina in practice

If you treat it as a dietary supplement and not a “medicine”, you can incorporate spirulina into healthy eating as an add-on. The key is spirulina quality, sensible use of spirulina and not expecting “instant results”. Instead of promising miracles, it is better to see it as one element of a bigger puzzle in which diet, movement, sleep and consistency matter most.