Written by the Plenthera team (orthomolecularly trained). Scientifically reviewed in April 2026. Last updated: April 30, 2026.
Spirulina is among the oldest life forms on Earth — a cyanobacterium that has been harnessing energy from sunlight through photosynthesis for billions of years. The Aztecs harvested it around Lake Texcoco; today, spirulina is cultivated worldwide in alkaline freshwater ponds. What makes it special: a protein content of 55-70% (one of the highest in a natural food), combined with phycocyanin, iron, beta-carotene, and B vitamins. At Plenthera, you'll find spirulina as powder and tablets, with traceable origin and microcystin-free certification.
Spirulina vs Chlorella — what suits you?
| Aspect | Spirulina | Chlorella |
|---|---|---|
| Type | Cyanobacterium | True green algae |
| Protein content | 55-70% | 50-60% |
| Main pigment | Phycocyanin (blue) | Chlorophyll (green) |
| Cell wall | None — directly absorbable | Hard — needs to be broken |
| B-vitamins | High (but pseudo-B12) | Present |
| Best for | Protein, energy, sport | Chlorophyll theme, detox research |
What is spirulina?
Spirulina (Arthrospira platensis) is a cyanobacterium — often called "blue-green algae", although strictly speaking it is not an algae but a photosynthetic bacterium. It is a protein-rich superfood containing phycocyanin, iron, and B vitamins.
Spirulina looks like a spiral filament under the microscope — hence its name. In nature, it floats in alkaline freshwater lakes in tropical and subtropical regions, such as Lake Texcoco in Mexico (where the Aztecs harvested and traded it as "tecuitlatl"), Lake Chad in central Africa (where local communities still use it as "dihé"), and Lake Klamath in Oregon. For commercial production, spirulina is cultivated in controlled ponds with alkaline water — Hawaiian, Indian, Taiwanese, and Chinese production hubs are dominant.
What distinguishes spirulina nutritionally is the combination of properties: 55-70% protein (complete amino acid profile), 10-20% phycocyanin (a blue pigment-protein with research into antioxidant activity), beta-carotene, vitamin K, gamma-linolenic acid (GLA), bioavailable iron, and magnesium. One 5-gram serving provides approximately 3 grams of protein and a touch of almost all micronutrients — hence its position as a "superfood".
One important caveat: spirulina contains pseudo-B12 (corrinoids) that are not recognized by the human body as active B12. Vegans and vegetarians supplementing with B12 should use a specific methylcobalamin supplement for that purpose — do not rely on spirulina.
Science, phycocyanin, and EFSA status
Spirulina is one of the most studied microalgae — thousands of publications exist on its composition and bioactive components. Much research focuses on phycocyanin: the blue pigment-protein that gives spirulina its characteristic color and shows antioxidant and immunomodulatory activity in laboratory and animal models.
Important: there are NO EFSA-approved health claims specifically for spirulina as a whole. However, there are recognized claims for components in spirulina — for example, the general EFSA claims for iron (fatigue, immune system) and protein (muscle mass) — provided the specific product meets the threshold.
Therefore, we do not make literal claims of specific effects for spirulina. Spirulina is a dietary supplement, not a medicine. If using medication (especially immunosuppressants and blood thinners): consult a doctor or pharmacist beforehand.
Quality and purity — what to look out for
Spirulina is sensitive to cultivation conditions. In uncontrolled wild lakes, other cyanobacteria species can occur that produce microcystins — toxins harmful to the liver and nervous system. The NVWA (Netherlands Food and Consumer Product Safety Authority) emphasizes the importance of quality control for algae supplements. High-quality spirulina comes from controlled ponds where these toxins are regularly tested.
Microcystin test: Proves that the product is free of cyanotoxins. Laboratory report available.
Heavy metals: Spirulina can accumulate heavy metals from contaminated water. Testing for lead, mercury, cadmium, and arsenic is essential.
Organic certificate: Guarantees no pesticides or synthetic fertilizers.
Traceable origin: Hawaiian, Taiwanese, and Indian production are known for stricter quality control.
At Plenthera, we exclusively work with spirulina of verified origin, with laboratory reports available upon request.
The spirulina forms at Plenthera
Spirulina powder
Finely ground spirulina — deep blue-green in color, with the typical marine aroma. To mix into smoothies, juices, or energy bars. For those who prefer the wholefood route.
Spirulina tablets
Pressed tablets without binders or fillers — 100% pure spirulina. Practical for on-the-go and for those who find the taste of the powder strong.
Spirulina + chlorella combination
Both microalgae combined for a broader profile — spirulina for protein and B vitamins, chlorella for chlorophyll and cell wall-binding properties.
How do you use spirulina?
Simple basic approach for spirulina:
- Determine your goal: daily supplement (3-5 g), sports use (5-10 g), or microdose (1-2 g).
- Choose the form: powder for smoothies, tablets for on-the-go, combination for a broad profile.
- Start with a low dose (1-2 g) and gradually increase to allow your digestion to adjust.
- Mix the powder into a smoothie or juice with a strong flavor (mango, pineapple) — softens the marine aroma.
- Can be taken with or without food; for a sensitive stomach, preferably with a meal.
- For B12 supplementation: DO NOT use spirulina as the sole source — choose a methylcobalamin supplement.
- If using medication (immunosuppressants, blood thinners): consult beforehand.
Myths and misconceptions about spirulina
Myth 1: "Spirulina is a good B12 source for vegans."
Incorrect and dangerous to claim. Spirulina contains pseudo-B12 (corrinoids) that are not recognized by humans as active B12. Vegans and vegetarians should use a specific methylcobalamin supplement — do not rely on spirulina.
Myth 2: "The more spirulina, the more protein and energy."
Spirulina is protein-rich in dry matter, but due to the low typical daily dose (3-5 g), it provides only 1.5-3.5 grams of protein per serving in absolute terms. Compare that to 20-30 grams of protein in a serious meal. Spirulina is a supplement, not a primary protein source.
Myth 3: "Spirulina detoxes heavy metals from the body."
The opposite can be true if spirulina itself is contaminated with heavy metals. There is no EFSA-approved evidence for "detox" claims. The body has its own detox system (liver and kidneys) — supplements can support this, not replace it.
Myth 4: "All spirulina is equally safe."
Incorrect. Spirulina from uncontrolled sources can contain microcystins, heavy metals, or other contaminants. Only choose spirulina with a laboratory-tested profile and organic certificate.
Combining spirulina with other supplements
Spirulina is often combined with other supplements for a broader nutritional profile. Popular combinations include:
- Chlorella: complementary microalgae — both together provide a broader profile.
- Vitamin B12 (methylcobalamin): since spirulina does not provide active B12, a separate B12 is essential for vegans.
- Vitamin C: combine with spirulina-iron for optimal absorption.
- Vegan protein: for those who want protein as the main category — spirulina as a micronutrient bonus.
- Maca: superfood combination for energy theme.
- Acerola: natural vitamin C source, complementary to iron in spirulina.
Frequently Asked Questions
What is spirulina?
Spirulina (Arthrospira platensis) is a cyanobacterium — often called blue-green algae. Protein-rich (55-70%) with phycocyanin, iron, and B vitamins.
How does spirulina work?
Spirulina provides protein, minerals, and pigments such as phycocyanin. Research focuses on antioxidant and immunomodulatory activity. EFSA claims specifically for spirulina do not exist.
How much spirulina per day?
3-5 grams as a general daily portion. For more intensive use, up to 10 grams per day, possibly divided over two moments.
When to take spirulina?
Timing is flexible. For a sensitive stomach: with a meal. Many users take spirulina in the morning in a smoothie.
What is the difference between spirulina and chlorella?
Spirulina is a cyanobacterium with a blue-green color, no cell wall, high protein content. Chlorella is a true green algae with a hard cell wall (must be broken) and high chlorophyll content.
Is spirulina a good B12 source?
No. Spirulina contains pseudo-B12 that is not recognized by humans as active B12. Vegans should use a methylcobalamin supplement.
Does spirulina help with detox?
No EFSA-approved detox claims for spirulina. What is referred to as "detox" is usually the natural function of the liver and kidneys.
Does spirulina have side effects?
Generally well-tolerated. Some report mild stomach upset or headache at the start. If using medication, consult beforehand.
Spirulina for vegans — protein?
Spirulina is protein-rich in dry matter, but due to the low daily dose (3-5 g), it provides little protein in absolute terms. It is a supplement, not a primary source.
How do I recognize quality spirulina?
Traceable origin, organic certificate, microcystin test, and heavy metals test. Ask for laboratory reports.
Sources
- EFSA Scientific Opinion on the safety of "spirulina" — Novel Food assessment.
- Karkos PD. et al., "Spirulina in clinical practice: evidence-based human applications", Evid Based Complement Alternat Med (2011).
- Watanabe F. et al., "Pseudovitamin B12 is the predominant cobamide of an algal health food, spirulina tablets", J Agric Food Chem (1999).
- WHO/FAO — Codex Alimentarius standards for cyanobacteria.
Disclaimer: This text is intended for informational purposes only and does not replace medical advice. Spirulina is a dietary supplement, not a medicine. In case of doubt or if using medication, we recommend consulting a doctor or orthomolecular therapist first.