Objective: This study aimed to investigate the effective- ness of spirulina supplementation in improving growth parameter outcomes among malnourished children.

Methods: This study followed a systematic review and meta-analysis design. The inclusion criteria were experi- mental spirulina supplementation studies in children with chronic malnutrition, which were published in English between 2006 and 2025. Studies involving adult partici- pants, and literature reviews, systematic reviews, and comprehensive reviews were excluded. A comprehensive search was conducted across five electronic databases: PubMed, Scopus, Wiley, ProQuest, and Emerald Insight.

The quality of the included studies was assessed with the Joanna Briggs Institute Critical Appraisal Checklist. Data were quantitatively synthesized in Review Manager version 5.4. This review was prospectively registered in PROSPERO (CRD420251069286).

Results: Seven studies in 1335 participants met the in- clusion criteria. The meta-analysis indicated significant increases in weight (SMD = 0.33, 95 % CI [0.22, 0.45], p < 0.00001, I 2 = 95 %) and MUAC (SMD = 0.71, 95 % CI [0.31, 1.11], p = 0.0005, I 2 = 67 %), but no significant effect on height (SMD = − 0.25, 95 % CI [− 1.36, 0.85], p = 0.65, I 2 = 98 %), among children receiving spirulina supplementation.

Conclusion: Spirulina supplementation was found to have significant positive effects on weight and MUAC in children with chronic malnutrition, but no significant improvement in height. These findings support spirulina’s potential role as a complementary intervention in nutri- tional programs targeting undernourished children.