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Reviewed by the Scan Dose Research Team and Clinical Advisory Board

Spirulina

STRONG EVIDENCESupplementLast updated April 5, 2026

SCAN DOSE SUMMARY

Spirulina is a cyanobacterium (not technically algae) rich in nutrients, antioxidants, and bioactive pigments. Our research, from 46 RCTs, 5 meta-analyses, and 4,957 participants, shows Grade A evidence for reducing oxidative stress and moderate evidence for improving lipid profiles, blood glucose, body composition, and allergy symptoms. The main concern: contamination. Spirulina can accumulate heavy metals and toxic cyanobacteria from its growth environment. Quality sourcing is critical.

EVIDENCE GRADES

Oxidative Stress BiomarkersStrong
A
Lipid profiles (LDL, HDL, total cholesterol)Moderate
B
Blood GlucoseModerate
B
Weight/Body FatModerate
B
Allergy SymptomsModerate
B

OPTIMAL DOSAGE

  • General health: 2-10g/day dried spirulina powder
  • For lipid improvement: 4-10g/day
  • For allergy relief: 2g/day
  • Higher doses more effective for metabolic outcomes
Scan a supplement containing Spirulina

DRUG INTERACTIONS

Hepatotoxic drugsSevere

Additive liver risk

Monitor liver function.

BP-lowering drugsMinor

Additive BP reduction

Monitor BP.

Blood-glucose-lowering drugsMinor

Additive glucose reduction

Monitor blood glucose.

CYP1A2/CYP2E1 substratesUnknown

May alter drug levels

Be aware.

ImmunosuppressantsUnknown

May reduce drug effectiveness

Use caution.

Blood thinnersUnknown

May increase bleeding risk

Monitor.

SAFETY PROFILE

Side Effects

  • Common: Diarrhea, headache, dizziness, abdominal pain (also seen with placebo)
  • Rare (case reports): Rhabdomyolysis, anaphylaxis, liver toxicity, autoimmune skin condition exacerbation

Drug Interactions

Precautions

  • Pregnancy/Breastfeeding: Avoid. Safety not established. Contamination concerns.
  • Children: Avoid. Potential microcystin contamination risk.
  • Autoimmune conditions: Use with caution. May exacerbate.
  • Dose AI finding: Pure Hawaiian Spirulina had elevated cadmium.

Quality Concerns

  • Heavy metal contamination possible depending on growth environment
  • Cyanobacteria contamination can introduce hepatotoxic microcystins
  • Third-party testing essential

WADA Status

Not Prohibited.

WHO SHOULD BE CAREFUL

QUALITY CONCERNS

  • Heavy metal contamination possible depending on growth environment
  • Cyanobacteria contamination can introduce hepatotoxic microcystins
  • Third-party testing essential

HOW SCAN DOSE SCORES THIS

Present at 2-10g, third-party tested:✅ Green flag — strong evidence for antioxidant and metabolic benefits
No third-party testing:⚠️ Yellow flag — contamination risk is real
From unknown/unverified source:🔴 Red flag — heavy metals and microcystin risk

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Reviewed by the Scan Dose Research Team and Clinical Advisory Board | Last updated: April 5, 2026

Not medical advice. Based on published clinical research and systematic reviews.

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