Know2eat

Spirulina

Arthrospira platensis

What spirulina has been studied for

3 associations assessed — 2 with at least some human evidence behind them. Strongest first.

  • 1 Moderate
  • 1 Limited
  • 1 Insufficient
4 things to know first — allergies, interactions and intake limits

About spirulina

A filamentous cyanobacterium grown commercially in alkaline ponds and sold mainly as a dried powder. It is a bacterium rather than a plant or a true alga, despite being sold among the seaweeds.

Also known as Blue-green algae, Arthrospira, Dihe, Tecuitlatl

Heart HealthWomen's Health

The evidence in depth

Best supported: Moderate

What each association actually rests on, and the papers behind it. A rating describes the state of the research, not how impressive the food is. How we rate evidence.

Blood lipid profile

Heart Health
Moderate evidence

Several meta-analyses of spirulina supplementation report reductions in total cholesterol, LDL and triglycerides. The underlying trials are small, mostly short, heavily concentrated in a few countries and often at high risk of bias, and they use gram doses of dried powder rather than the food.

Moderate evidence. Several human studies point the same way, with real caveats.

3 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Healthy blood pressure

Heart Health
Limited evidence

Pooled analyses suggest small reductions in systolic blood pressure with spirulina supplementation, mostly in people with raised pressure to begin with. The effect is inconsistent across trials and the studies are small.

Limited evidence. Early human work, or mostly lab and animal research.

4 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Iron status

Women's Health
Insufficient evidence

Spirulina is often recommended for iron deficiency because it is iron-dense by weight. Realistic servings supply modest amounts, absorption from it has barely been studied, and no trial has shown that it corrects deficiency.

Insufficient evidence. Not enough human research to say anything useful yet.

3 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Ask about Spirulina

Ask about Spirulina

Answers are written only from the entries on this page — the same nutrients, compounds, claims and citations you can read above. Nothing is added from outside the database, and every answer lists what it was built from.

AI explanations are not switched on for this site, so there is nothing to ask here. Everything above is read straight from the database and does not need them.

Key nutrients

Nutrient content per 100 grams
NutrientAmount% DV
Macronutrients
Calories26 kcal1%
Protein5.92 g12%
Total fat0.39 g1%
Carbohydrate2.42 g1%
Fibre0.4 g1%
Total sugars0.3 g—
Water90.7 g—
Fats
Saturated fat0.135 g1%
Monounsaturated fat0.034 g—
Polyunsaturated fat0.106 g—
Cholesterol0 mg0%
Linoleic acid (omega-6)0.064 g—
Vitamins
Vitamin A3 µg0%
Vitamin C0.9 mg1%
Vitamin D0 µg0%
Vitamin E0.49 mg3%
Vitamin K2.5 µg2%
Thiamin (B1)0.222 mg19%
Riboflavin (B2)0.342 mg26%
Niacin (B3)1.2 mg7%
Pantothenic acid (B5)0.325 mg7%
Vitamin B60.034 mg2%
Folate9 µg2%
Vitamin B120 µg0%
Choline6.5 mg1%
Minerals
Calcium12 mg1%
Iron2.79 mg16%
Magnesium19 mg5%
Phosphorus11 mg1%
Potassium127 mg3%
Sodium98 mg4%
Zinc0.2 mg2%
Copper0.597 mg66%
Manganese0.186 mg8%
Selenium0.7 µg1%
Other measured compounds
Beta-carotene33 µg—
Alpha-carotene0 µg—
Lycopene0 µg—
Lutein + zeaxanthin0 µg—
Caffeine0 mg—
Ash0.6 g—

Nutrient values are per 100 g of the USDA reference entry named on this page and vary with variety, growing conditions, storage and preparation.

Source record: Seaweed, spirulina, raw (USDA FoodData Central, FDC ID 170091).

% DV uses the FDA Daily Values for adults and children aged 4 and over. A dash means no Daily Value has been established for that nutrient.

Bioactive compounds

Compounds present in meaningful amounts. Presence is banded rather than quantified, because whole-food levels vary enormously with variety, growing conditions, storage and preparation.

How preparation changes things

Only effects with real support are listed. If a preparation method is missing, it is because nothing dependable is documented — not because it makes no difference.

Nothing dependable is recorded about how preparation changes this food’s nutritional properties. Rather than guess, this section stays empty.

Things to know

Allergies, interactions and intake concerns. Every food gets this section — a reference where everything is uniformly good is not a reference.

  • Avoid

    Microcystin contamination

    Spirulina grown in open ponds can be contaminated with other cyanobacteria that produce microcystins, which are potently toxic to the liver. Contaminated products have repeatedly been found on the market. Buy from manufacturers who test for microcystins, and be aware that the risk is highest in cheap unbranded powders.

  • Avoid

    Phenylketonuria

    Spirulina is very high in phenylalanine and must be avoided by anyone with phenylketonuria.

  • Worth knowing

    Autoimmune conditions and immunostimulant effects

    Spirulina activates immune signalling in laboratory work, and case reports describe autoimmune flares, including dermatomyositis, following its use. The causal link is not established, but caution is reasonable for anyone with an autoimmune condition.

  • Worth knowing

    The USDA record is for the wet form

    Nutrient figures here describe raw spirulina, not the dried powder, which is roughly ten times more concentrated by weight. Comparing this panel to a supplement label will mislead.