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Spirulina

What does the research say about Spirulina?

3 health outcomes synthesised

Spirulina, a blue-green algae, has been researched for 3 health outcomes: reduced body weight, reduced diastolic blood pressure, and reduced body mass index. The strongest evidence, involving 5 studies, supports a small beneficial effect on reducing body weight in overweight and obese adults, with doses ranging from 20 mg to 6 g daily. No consistent effective dose has been identified across studies.

Strongest evidence: Moderate-strength evidence from 5 studies shows a small beneficial effect of spirulina supplementation on reducing body weight (e.g., g = -0.30, 95% CI: -0.53 to -0.08; WMD: -1.78 kg), primarily in overweight and obese adults. Doses ranged from 20 mg to 6 g daily, with no consistent effective dose. For diastolic blood pressure, 3 studies consistently found moderate reductions (e.g., -2.84 to -3.09 mmHg), and for body mass index, 3 studies reported small-to-moderate reductions (e.g., WMD: -0.58 kg/m²), both with moderate evidence strength.

Mixed or weaker evidence: No outcomes had low or very low evidence strength; all three outcomes are supported by moderate-strength evidence. However, the evidence bases for diastolic blood pressure and BMI are small (only 3 studies each), making conclusions preliminary.

Effective dose patterns: Across all outcomes, doses varied widely from 20 mg to 6 g daily, and no single effective dose range emerged. Study durations were inconsistently reported, limiting time-to-effect assessments.

Population insights: The most studied populations are overweight and obese adults, and adults with metabolic syndrome. One neutral finding for body weight occurred in children and adolescents, suggesting age may moderate the effect.

Notable caveats: All three outcomes are subject to possible publication bias, as null-result studies are less likely to be published or indexed. The evidence base is small for diastolic blood pressure and BMI, and study durations were not consistently reported.

Frequently asked

  • What is Spirulina good for according to research?
    Research shows moderate-strength evidence that spirulina supplementation is associated with small reductions in body weight (4 of 5 studies beneficial) and body mass index (3 of 3 studies beneficial), as well as moderate reductions in diastolic blood pressure (3 of 3 studies beneficial). Effects are most studied in overweight and obese adults.
  • What dose of Spirulina is typically used in studies?
    Doses in clinical studies ranged widely from 20 mg to 6 g daily across all outcomes. However, no consistent effective dose has been identified, and study durations were not consistently reported.
  • Who benefits most from Spirulina?
    The strongest evidence for benefits is in overweight and obese adults and adults with metabolic syndrome. One neutral finding for body weight in children and adolescents suggests that age may moderate the effect, with adults likely benefiting more.
  • Are there caveats or limitations in the research on Spirulina?
    Yes. All outcomes are subject to possible publication bias, as null-result studies are less likely to be published. The evidence bases for diastolic blood pressure and BMI are small (only 3 studies each), making conclusions preliminary. Dosing and study durations were inconsistently reported, limiting precision.
  • Does Spirulina help with reducing body weight?
    Moderate-strength evidence from 5 studies suggests a small beneficial effect of spirulina on reducing body weight, with 4 studies reporting beneficial results and 1 neutral finding in children and adolescents. The reduction is statistically significant but small (e.g., -1.78 kg).
  • Does Spirulina help with reducing blood pressure?
    Moderate-strength evidence from 3 studies shows spirulina is consistently associated with moderate reductions in diastolic blood pressure (e.g., -2.84 to -3.09 mmHg). However, the evidence base is small, and conclusions should be considered preliminary.

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