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Spirulina

Spirulina is a non-toxic blue-green algae. It's rich in nutrients and may have some general cardiovascular and anti-aging benefits. Its potentially potent immunomodulating properties may give it additional uses such as ameliorating allergies and asthma, but more research is needed.

Our evidence-based analysis on spirulina features 228 unique references to scientific papers.

Research analysis led by and reviewed by the Examine team.
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Summary of Spirulina

Primary information, health benefits, side effects, usage, and other important details

What is spirulina?

Spirulina is a type of non-toxic blue-green algae (cyanobacteria). It may refer to a number of different species in the Arthrospira genus, namely platensis and maxima. Spirulina is often used as a vegan source of protein and iron and is rich in a variety of other nutrients and phytochemicals. It is believed by some to provide vitamin B12, but it actually contains the dubious pseuodovitamin B12 which hasn't been shown to be effective. Spirulina has a few notable active components. The main ingredient is called phycocyanobilin, which makes up about 1% of spirulina. This compound mimics the body’s bilirubin compound, in order to inhibit an enzyme complex called nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. By inhibiting NADPH oxidase, spirulina provides potent antioxidative and anti-inflammatory effects.

What are spirulina's benefits?

Evidence suggests a general improvement in the basic components of the lipid panel: triglycerides, HDL, LDL, VLDL, and total cholesterol. It seems to reduce blood pressure by a small amount, and may have some meaningful effects on liver enzymes and overall liver health, though more research is needed on that. It also seems to improve general antioxidant status and reduce markers of oxidative stress, as well as some inflammatory markers. When people take spirulina, they tend to lose a small amount of weight, even if they're not trying to, and there's some evidence to suggest that it can help regulate appetite.

Because of its potentially potent immunomodulating properties, spirulina may have utility for preventing allergic reactions and treating asthma. However, there's only a small amount of research for these indications. Another possible benefit is improved athletic performance, with both resistance and endurance exercise, but the evidence is still preliminary.

What are spirulina's side-effects and drawbacks?

While most spirulina products are safe, there have been reports of contamination with toxic microcystins from other bacteria. It is advisable to ensure that any spirulina products have been throughly tested for safety before consumption. In general, spirulina is safe and adverse events aren't common in clinical trials.

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How to Take

Recommended dosage, active amounts, other details

The dose of spirulina used in studies examining its effects vary greatly. In general, 1-8 g per day of spirulina has been shown to have some effect. The specific doses depend on the condition its being used for:

  • For cholesterol, doses in the range of 1-8 g per day may be impactful

  • For muscle performance, doses of 2-7.5 g per day have been used

  • For blood glucose control, very mild effects have been seen with 2 g per day

  • Blood pressure may be affected at doses of 3.5-4.5 g per day

  • Effects for fatty liver have been seen at doses of 4.5 g per day

Spirulina is about 20% C-phycocyanin by weight, and about 1% phycocyanobilin by weight. The dosage range of 200mg/kg C-phycocyanin (1g/kg spirulina) converted to human equivalent doses from rats is approximately:

  • 11.0g for a 150lb person

  • 14.5g for a 200lb person

  • 18.2g for a 250lb person

Further research is needed to determine whether spirulina should be taken once a day, or in smaller doses, multiple times per day.

It is not recommended to exceed the highest dose mentioned above, as no clear benefits have been noted beyond that level.

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Human Effect Matrix

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The Human Effect Matrix summarizes human studies to tell you what effects Spirulina has on your body, how much evidence there is, and how strong these effects are.

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Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Outcome Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
Notes
grade-a Notable Very High See all 18 studies
In populations with metabolic syndrome or related morbidities (diabetes, hyperlipidemia, hypertension, etc.) spirulina in a variety of doses between 1-8g daily is able to reduce triglycerides up to 10-15%. For people without elevated cardiovascular risk factors, there may be some effect as well, though less pronounced.
grade-a Minor Very High See all 16 studies
A positive influence of spirulina on HDL-C appears to be present, but the magnitude of benefit is not overly remarkable and varies depending on the disease state (with states associated with fatty liver having a much greater increase in HDL-C seen with spirulina)
grade-a Minor Very High See all 16 studies
Degree of efficacy seems variable and correlated with disease state (more drastic improvements when LDL-C is much higher) but currently does not appear to be overly remarkable unless fatty liver exists.
grade-a Minor Very High See all 16 studies
Reductions in cholesterol seen are positive, but not overly remarkable
grade-b Notable Very High See all 4 studies
More research is needed, but from what we have, it appears that a moderate beneficial effect is likely.
grade-b Notable Very High See all 3 studies
A notable increase overall has been found in one meta-analysis.
grade-b Minor Moderate See all 8 studies
Insufficient evidence to fully evaluate the effects on blood pressure, but in the context of hypertension, a small but meaningful effect is likely.
grade-b Minor Very High See all 8 studies
Reductions in blood glucose seen are not overly remarkable but one meta-analysis found a small, statistically significant reduction.
grade-b Minor Very High See 2 studies
There's likely a decrease for people with metabolic syndrome, though the effect is small, and the number of studies is small as well.
grade-b Minor Very High See all 5 studies
A small reduction has been found in one meta-analysis, though more research is needed to determine how consistent or potent it is.
grade-b Minor Very High See all 4 studies
Studies have mostly found a reduction, but more research is needed to confirm its potency and reliability.
grade-b Minor Very High See all 5 studies
Some studies have found small reductions, but the research is inconsistent, and more is needed to determine its potency and reliability.
grade-b Minor Very High See all 14 studies
Overall, a meta-analysis found a small but statistically significant reduction, with a greater effect from higher doses.
grade-b Minor Very High See 2 studies
A small reduction has been found in one meta-analysis, based on 5 trials.
grade-b - Very High See all 3 studies
No apparent effect overall. More research specifically in poorly controlled diabetes is needed.
grade-b - Very High See all 4 studies
One meta-analysis failed to find an effect overall, with the research being highly inconsistent.
grade-c Strong Very High See 2 studies
Two studies found that spirulina is strongly effective in controlling allergies, with the symptoms of nasal discharge, sneezing, nasal congestion, and itching being reduced, and smell being improved. According to self-reports in one study, more than twice as many subjects in the spirulina group reported more than a 2-fold increase in satisfaction with treatment. In another study, it was comparable to or even more potent than the comparator pharmaceutical drug. More research is needed.
grade-c Strong Very High See 2 studies
The decrease in nasal congestion seen in the both studies was remarkably strong relative to placebo, and comparable to a comparator pharmaceutical drug in another study, both in regards to allergic rhinitis; it is not sure if this applies to other causes of nasal congestion.
grade-c Notable Very High See all 5 studies
Preliminary evidence suggests the reduction of liver enzymes correlates with the degree of liver damage somewhat, and this is notable since the reduction of liver fat seen is strongly effective at this moment in time.
grade-c Notable - See study
The lesions were fully healed in 44% of the 1g spirulina group relative to 7% of the placebo; although no reference drug was used.
grade-c Minor Very High See 2 studies
Two studies found a small increase but neither was statistically significant.
grade-c Minor Very High See all 5 studies
Although increases have been noted in glutathione peroxidase and superoxide dismutase, it is difficult to predict when it will be most effective and more research is needed.
grade-c Minor - See study
Somewhat effective, but requires more evidence; no reference drug was used to compare
grade-c Minor High See all 4 studies
A small reduction has been found in most studies. More research is needed to determine when and how it's most useful.
grade-c Minor - See study
Nothing remarkable in the one study on fat oxidation rates during exercise.
grade-c Minor - See study
Requires more evidence to establish its potency
grade-c Minor Very High See all 4 studies
Studies have mostly found a reduction, but more research is needed to confirm its potency and reliability.
grade-c Minor Moderate See all 3 studies
Studies currently assessing the effects of spirulina on muscular endurance are too hetereogeneous to properly assess potency thereof. However, a positive effect does appear to exist
grade-c Minor Very High See all 4 studies
Improvements have been seen during various types of training, the one negative study being on rowing power. More research is needed to determine any contexts which it might reliably work for.
grade-c Minor - See study
Although there was some promising evidence, it did not appear overly remarkable and requires further evidence.
grade-c Minor Very High See 2 studies
Minor increase, needs more evidence in a non-aged cohort to assess potency
grade-c - - See study
Currently insufficient evidence to support a change in RBC count.
grade-d Strong - See study
Although only based on a series of case studies at this moment in time, the reduction of liver fat seen after 3 months was remarkably effective
grade-d Notable - See study
One study found a reduction.
grade-d Notable - See study
One study found a notable effect.
grade-d Notable - See study
One study found an increase comparable to medication.
grade-d Notable - See study
One study found an increase comparable to medication.
grade-d Notable - See study
One study found a notable reduction.
grade-d Notable - See study
One study found a notable reduction.
grade-d Notable - See study
One study found a notable increase.
grade-d Notable Very High See 2 studies
Two studies found a notable reduction overall.
grade-d Notable - See study
NK cell activity against a tumor cell line (K562) increased 40% following a week ingestion of fairly reasonable oral dosing, suggesting that this is a notable increase of possible interest.
grade-d Notable Very High See 2 studies
The increases in mRNA content of natural killer cell content increased 37-55% (NKG2D) and 75% (perforin) which appeared to be dose-dependent, a possibly potent immunostimulatory effect.
grade-d Notable - See study
Notably effective as it trended to outperform Milk Thistle, which is a good reference supplement in regards to a sustained virologic response (not the best comparison, however)
grade-d Minor High See all 3 studies
There may be a small reduction in some cases, but more research is needed to know when this occurs.
grade-d Minor - See study
One study found a reduction.
grade-d Minor - See study
One study found a non-significant reduction in chemotherapy.
grade-d Minor - See study
There was a reduction in one study in chemotherapy
grade-d Minor - See study
One study found an improvement in mathematical ability.
grade-d Minor High See all 3 studies
A small increase has been found more often than not.
grade-d Minor - See study
One study found an increase.
grade-d
Minor
- See 2 studies
A reduction for cancer patients undergoing chemotherapy and increase in healthy, elderly participants. More research is needed in both contexts.
grade-d Minor - See study
One study found a reduction but it wasn't statistically significant.
grade-d Minor Moderate See 2 studies
Mixed evidence. The reduction in allergic rhinitis patients is quite notable, however.
grade-d Minor - See study
One study found a reduction.
grade-d
Minor
- See study
An initial reduction in the 24 hours after exercise but an increase after that.
grade-d Minor - See study
One study found a reduction.
grade-d
Minor
- See study
One study found different effects in different cycles of chemotherapy.
grade-d Minor - See study
One study found a reduction during submaximal exercise.
grade-d Minor - See study
One study found an increase.
grade-d Minor - See study
One study found an increase, though it was smaller than for medication.
grade-d Minor - See study
One study found an increase.
grade-d Minor - See study
One study found an increase.
grade-d Minor Very High See 2 studies
A couple of studies have found a reduction. More research is needed.
grade-d Minor - See study
One study found an increase.
grade-d Minor High See all 3 studies
Two out of 3 studies found an increase.
grade-d Minor - See study
One study found a reduction post-exercise.
grade-d Minor - See study
One study found an increase.
grade-d Minor - See study
One study found a reduction.
grade-d Minor - See study
One study found a reduction.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - Moderate See 2 studies
Mixed evidence in two studies.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - High See all 3 studies
One study found an improvement but the overall evidence is inconsistent and unclear.
grade-d - Very High See 2 studies
Currently no evidence to support an improvement in fatigue symptoms
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See 2 studies
Mixed evidence during exercise.
grade-d - Moderate See 2 studies
Inconsistent evidence from two studies. More research is needed.
grade-d - Very High See 2 studies
No apparent effect.
grade-d - - See 2 studies
Mixed evidence, more research is needed.
grade-d - Moderate See 2 studies
No apparent effect overall.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - Moderate See 2 studies
One study found an increase while another one didn't find an effect.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - - See study
No apparent effect in one study.
grade-d - Very High See 2 studies
No apparent effect in two studies.
grade-d - - See study
No apparent effect in one study.

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Frequently Asked Questions and Articles on Spirulina

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Things to Note

Caution Notice

Some users may possess allergies to spirulina (infrequent)

May interact with enzymes of drug metabolism

  • An allergic reaction to spirulina has been reported, although overall frequency of allergic responses or cross-sensitivities are not yet known

  • Preliminary evidence has suggested a reduction in the activities of the enzymes CYP2C6, CYP1A2, and CYP2E1

  • The same evidence has noted an upregulation (increase in activity) for both CYP2B1 and CYP3A1

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Click here to see all 228 references.