Spirulina (Arthrospira/Spirulina) Evidence

Evidence posture

Some human evidence supports modest blood-pressure lowering in selected adults, but the trial base is limited and generic cardiometabolic claims remain uncertain.

What the evidence supports

A GRADE-assessed systematic review and meta-analysis of randomized trials reported modest reductions in systolic and diastolic blood pressure, particularly in several higher-risk subgroups. The authors still noted a low number of studies and participants and an unresolved dose-response relationship.

Studied context

Randomized trials use different spirulina preparations, doses, populations, and intervention durations. Blood-pressure findings should not be generalized to unrelated outcomes or to products with undisclosed amounts.

Safety context

LiverTox reports that controlled trials generally have not shown liver enzyme elevations or clinically apparent liver injury, but rare possible liver-injury reports exist. Commercial spirulina can also be contaminated with toxin-producing cyanobacteria, making product quality relevant.

Product directness

V-CONTROL lists spirulina algae extract but does not disclose the amount, extract characterization, or contaminant testing on the tracked manufacturer page. Trial results therefore cannot be directly assigned to the product.

Products that list this ingredient/category

Primary and authoritative sources

Review-level evidence highlights

The Effect of Spirulina Supplementation on Blood Pressure in Adults: A GRADE-Assessed Systematic Review and Meta-Analysis of Randomized Clinical Trials (GRADE-assessed systematic review and meta-analysis of randomized controlled trials; PMID 39529406)

Population/scope: Adults in randomized trials of spirulina supplementation

Evidence scope: Systolic and diastolic blood pressure

Finding: The pooled analysis reported modest reductions in systolic and diastolic blood pressure.

Limitations: The number of studies and participants was limited, heterogeneity was present, and dose-response/meta-regression did not establish a clear intervention threshold.

Directness: Relevant human evidence · verified 2026-10-02

Important: Ingredient-level evidence is not proof that a finished product has the same effect. Dose, form, population, duration, and formulation must match.