Clinical Safety of a High Dose of Phycocyanin-Enriched Aqueous Extract from Arthrospira (Spirulina) platensis: Results from a Randomized, Double-Blind, Placebo-Controlled Study with a Focus on Anticoagulant Activity and Platelet Activation

J Med Food. 2016 Jul;19(7):645-53. doi: 10.1089/jmf.2015.0143. Epub 2016 Jun 30.


The goal for this study was to evaluate safety regarding anticoagulant activity and platelet activation during daily consumption of an aqueous cyanophyta extract (ACE), containing a high dose of phycocyanin. Using a randomized, double-blind, placebo-controlled study design, 24 men and women were enrolled after informed consent, and consumed either ACE (2.3 g/day) or placebo daily for 2 weeks. The ACE dose was equivalent to ∼1 g phycocyanin per day, chosen based on the highest dose Generally Recognized as Safe (GRAS) by the U.S. Food and Drug Administration. Consuming ACE did not alter markers for platelet activation (P-selectin expression) or serum P-selectin levels. No changes were seen for activated partial thromboplastin time, thrombin clotting time, or fibrinogen activity. Serum levels of aspartate transaminase (AST) showed a significant reduction after 2 weeks of ACE consumption (P < .001), in contrast to placebo where no changes were seen; the difference in AST levels between the two groups was significant at 2 weeks (P < .02). Reduced levels of alanine transaminase (ALT) were also seen in the group consuming ACE (P < .08). Previous studies showed reduction of chronic pain when consuming 1 g ACE per day. The higher dose of 2.3 g/day in this study was associated with significant reduction of chronic pain at rest and when physically active (P < .05). Consumption of ACE showed safety regarding markers pertaining to anticoagulant activity and platelet activation status, in conjunction with rapid and robust relief of chronic pain. Reduction in AST and ALT suggested improvement in liver function and metabolism.

Keywords: P-selectin; anticoagulant activity; blood pressure; chronic pain; liver enzymes; platelet.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Alanine Transaminase / blood
  • Anticoagulants / administration & dosage*
  • Aspartate Aminotransferases / blood
  • Chronic Pain / drug therapy
  • Double-Blind Method
  • Female
  • Fibrinogen / metabolism
  • Humans
  • Male
  • Middle Aged
  • P-Selectin / blood
  • Partial Thromboplastin Time
  • Phycocyanin / administration & dosage*
  • Phycocyanin / adverse effects*
  • Placebos
  • Platelet Activation / drug effects*
  • Spirulina / chemistry*
  • Thrombin Time


  • Anticoagulants
  • P-Selectin
  • Placebos
  • Phycocyanin
  • Fibrinogen
  • Aspartate Aminotransferases
  • Alanine Transaminase