Therapeutic Efficacy of Spirulina Algae and N-Acetylcysteine in COVID-19 Hospitalized Patients: A Randomized Phase II Clinical Trial

Background: Spirulina algae are widely used in food, cosmetic, and dietary applications, and laboratory and clinical studies have reported their antiviral and immune-enhancing properties. Aim: We aimed to evaluate the prescription of spirulina, a safe food supplement with antiviral properties, and N-acetylcysteine in the treatment of hospitalized patients with Coronavirus Disease 2019 (COVID-19). Materials and Methods: This study was conducted as a multicenter, randomized, single-masked, open-label phase II clinical trial on 66 patients with COVID-19. Patients were randomly assigned to two intervention groups and one control group. The intervention groups were defined as follows: one group received spirulina algae (23 people), and the other group received N-acetylcysteine plus spirulina algae (21 people). In the control group (22 people), the patients only received the national standard treatment for COVID-19. The intervention groups were prescribed 80 mg/kg of spirulina green algae daily. Results: The duration of hospitalization (P = 0.874), Intensive Care Unit (ICU) admission (P = 0.320), and mortality (P = 0.320) of patients between the three groups did not show any significant difference. Side effects, including headache (P = 0.022) and nausea (P = 0.039), were significantly less common in the control group. No statistically significant difference was observed regarding the frequency of symptoms after discharge in the three-month follow-up (P = 0.420). Conclusion: Our study showed that administering spirulina with or without N-acetylcysteine did not affect the length of hospitalization, ICU admission, mortality, and the frequency of symptoms or long COVID.