Spirulina

Evidence status

Limited evidence to recommend for any consumer outcome yet.

45 papers · 0 claims · 133 outcomes scored

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 size 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

Track spirulina in the app

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Sources

Generated May 15, 2026