Beneficial effects of Chlorella species supplementation in the general population: a GRADE-assessed systematic review and dose–response meta-analysis

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Abstract

This systematic review and meta-analysis aimed to evaluate the potential benefits of Chlorella supplementation in the general population, with a focus on its impact across a broad spectrum of health-related biomarkers and clinical parameters. A comprehensive literature search was conducted in PubMed, CENTRAL, Web of Science, Scopus, and EMBASE databases was conducted up to February 20, 2025. A total of 24 studies were included. Chlorella supplementation led to significant reductions in body fat percentage (Weighted Mean Difference [WMD] = −0.73%, 95% Confidence Interval [CI]: −1.18 to −0.29), body mass index (BMI) (WMD = −0.30 kg/m², 95% CI: −0.48 to −0.13), weight (WMD = −1.28 kg, 95% CI: −2.00 to −0.56), waist-to-hip ratio (WMD = −0.01%, 95% CI: −0.02 to −0.01), homeostatic model assessment for insulin resistance (WMD = −0.22 units, 95% CI: −0.35 to −0.09), insulin (WMD = −0.86 μU/mL, 95% CI: −1.45 to −0.27), high sensitivity C-reactive protein (WMD = −0.56 μg/ml, 95% CI: −1.02 to −0.11), low-density lipoprotein cholesterol (WMD = −6.20 mg/dl, 95% CI: −8.33 to −4.08), total cholesterol (WMD = −8.03 mg/dl, 95% CI: −10.60 to −5.46), triglycerides (WMD = −2.91 mg/dl, 95%CI: −5.70 to −0.12), malondialdehyde (WMD = −1.84 nmol/ml; 95% CI: −3.24 to −0.45), and leptin levels (WMD = −0.71 ng/ml; 95% CI: −1.27 to −0.16). Conversely, catalase (WMD = 22.06 U/g.Hb; 95% CI: 3.19 to 40.93) increased significantly. While the evidence for BMI was rated as low, the certainty of evidence for most other outcomes was very low according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE). Our findings underscore the potential of Chlorella supplementation to support metabolic health in general population; however, given the overall very low certainty of evidence based on the GRADE assessment, these results should be interpreted cautiously.

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Authors and Affiliations

1. Students’ Scientific Research Center (SSRC), Tehran University of Medical Sciences, Tehran, Iran

   Helia Mardani

2. School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran

   Mohammad Amin Karimi

3. Department of Nutrition, Food Sciences and Clinical Biochemistry, School of Medicine, Social Determinants of Health Research Center, Gonabad University of Medical Science, Gonabad, Iran

   Mohammad Sharifi

4. Non-Communicable Diseases Research Center, Alborz University of Medical Sciences, Karaj, Iran

   Dorsa Ghazvineh

5. Department of Nutrition Research, National Nutrition and Food Technology Research Institute and Faculty of Nutrition Sciences and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran

   Zahra Yari

6. Student Research Committee, Department of Community Nutrition, Faculty of Nutrition Sciences and Food Technology, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran

   Ali Jafari

7. Systematic Review and Meta-analysis Expert Group (SRMEG), Universal Scientific Education and Research Network (USERN), Tehran, Iran

   Ali Jafari

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As a systematic review and meta-analysis, this manuscript did not necessitate review by our institutional clinical ethics committee

Competing interests

Ali Jafari holds an editorial position at Systematic Reviews. All other authors of this publication declare that they have no affiliations with, or involvement in, any organization or entity with a financial interest (including honoraria, educational grants, participation in speakers’ bureaus, memberships, employment, consultancies, stock ownership or other equity interests, expert testimony, or patent-licensing arrangements) or a non-financial interest (such as personal or professional relationships, affiliations, knowledge, or beliefs) relevant to the subject matter or materials discussed in this manuscript.

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Supplementary materials: Supplementary Tables 1–3, Supplementary Figures 1–5, and Supplementary References. (download DOCX )

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Mardani, H., Karimi, M.A., Sharifi, M. et al. Beneficial effects of Chlorella species supplementation in the general population: a GRADE-assessed systematic review and dose–response meta-analysis.
Nutr. Diabetes (2026). https://doi.org/10.1038/s41387-026-00449-3

• Received:22 August 2025

• Revised:10 June 2026

• Accepted:22 June 2026

• Published:08 July 2026

• DOI
  :https://doi.org/10.1038/s41387-026-00449-3