Positives

• Spirulina holds a 9.0/10 average on Drugs.com with 100% positive reviews; one patient reported four years of use alongside normal A1c (5.1), fasting glucose 82, and improvements in cholesterol and blood pressure Drugs.com.
• Patients on spirulina commonly describe improved immune resilience, with reports of increased antibody production and inhibition of mast-cell histamine release WebMD.
• Senior citizens on spirulina commonly see improvements in anemia and immune function, matching forum reports of better stamina and energy PMC.
• Patients on spirulina commonly report improved submaximal exercise performance and fatigue tolerance, consistent with reports of more usable energy Frontiers in Nutrition.

Negatives

• In four N-of-1 randomized controlled trials of patients with idiopathic chronic fatigue, spirulina did not produce a significantly different fatigue response than placebo — meaning it should not be expected to be a standalone fatigue treatment PubMed.
  
  

Hurdles & Side Effects

• Spirulina is contraindicated in patients with phenylketonuria (contains phenylalanine) and may stimulate the immune system enough to worsen autoimmune conditions; the high acute-COVID dose used in trials was 15 g/day, well above typical 1-3 g/day OTC dosing PubMed.