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Spirulina

Spirulina

Evidence status

Limited evidence to recommend for any consumer outcome yet.

45 papers · 0 claims · 133 outcomes scored

Evidence overview

Evidence overview

Spirulina shows modest benefits for cholesterol, fasting glucose, and exercise fatigue, with the clearest signal in lipid and glycemic markers and no convincing weight-loss effect.

  • Across 45 papers, spirulina improved lipid profiles and fasting glucose modestly, but changes stayed small rather than dramatic.2
  • Most trials used short courses and mixed doses, so product quality and dosing varied across studies.
  • Exercise-performance findings are secondary and less consistent than lipid or glucose outcomes.

Outcomes

What spirulina actually does, by outcome

Each row is one outcome with effect size, evidence base, the dose that worked in trials, and time to first effect. Magnitude tiers come from native-unit MCID where available, Cohen's d otherwise.

Outcome Effect Evidence Dose Weeks Rank

Forms & standardisation

The best human coverage comes from plain spirulina powder or tablets made from Spirulina platensis or Arthrospira platensis.124 On a label, look for the species name and a single-ingredient product, because the trial data usually tests spirulina itself, not a stacked blend.12 Quality matters here, so products that show contamination testing or third-party screening deserve extra points.5

Risk profile

Adverse events and known drug interactions

Safety events

anaphylaxis severe
nausea mild
bloating mild
giddiness mild
headache mild
nausea or vomiting (transient) mild
Gastrointestinal symptoms (stomach pain/cramp, constipation) mild
gastrointestinal discomfort mild

Drug interactions

Dexamethasone moderate decreases effect
Cyclophosphamide moderate decreases effect
Methotrexate moderate decreases concentration
Sodium Salicylate minor decreases effect
Betahistine minor unknown
Diosmin minor unknown

Frequently asked

Common questions

What does spirulina actually do?

The best human data points to modest support for cholesterol, fasting glucose, and exercise fatigue, not a dramatic all-purpose fix.234

When should you take spirulina?

Take it daily, usually with meals or split across the day, because that is how most trials dose it and it tends to sit better on your stomach.234

How long does spirulina take to work?

Most studies run for about 4 to 12 weeks, so that is the window to judge whether it is doing anything for you.234

Is spirulina safe to take every day?

Most people tolerate it, but nausea, bloating, headache, and rare serious allergy reports show up in the safety data, so stop if you react badly.5

Sources

  1. 1. Spirulina bioactive compounds and mechanisms, review
  2. 2. Spirulina supplementation and lipid profile, systematic review and meta-analysis
  3. 3. Spirulina supplementation and glycemic markers, systematic review and meta-analysis
  4. 4. Spirulina and exercise performance, systematic review
  5. 5. Spirulina safety and adverse effects, review

Generated May 15, 2026

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