Chlorella and Spirulina for heart risk factors
What it found
In people, Chlorella supplements made no difference to blood pressure or blood fats.
Spirulina lowered diastolic blood pressure slightly but did not change cholesterol or triglycerides.
What they found
Studies in people
Blood pressure with Chlorella
Chlorella supplements had a neutral effect on blood pressure compared with placebo. The authors note that people in these trials already had blood pressure near normal ranges.
Blood fats with Chlorella
Chlorella had no effect on total cholesterol, triglycerides, HDL cholesterol or LDL cholesterol when the results were pooled.
Diastolic blood pressure with Spirulina
Spirulina lowered diastolic blood pressure by a small amount compared with placebo. The authors describe this reduction as modest and of uncertain clinical importance.
Systolic blood pressure with Spirulina
Spirulina did not significantly change systolic blood pressure.
Blood fats with Spirulina
Spirulina did not significantly affect cholesterol or triglycerides, though there was a trend toward lower total cholesterol.
Side effects
None of the Chlorella or Spirulina studies reported adverse effects during the trial periods.
What the authors conclude
“This study demonstrated Spirulina microalgae's promise as a therapeutic adjuvant for blood pressure management, with a modest but significant reduction in diastolic blood pressure.”
Also in their conclusions
- They say Spirulina shows promise as an add-on for blood pressure management, with a small but significant drop in diastolic blood pressure.
- They advise that future trials should establish optimal dosing, likely 2000 to 8000 mg daily, and last at least 8 to 12 weeks.
- They call for more research into how Spirulina lowers blood pressure and for standardised reporting of outcomes.
How it was done
The authors wanted to see whether these microalgae could help control risk factors for heart and metabolic diseases, since existing studies were small and used different measures.
They searched PubMed for randomised controlled trials of Chlorella or Spirulina and found 12 Chlorella studies and 9 Spirulina studies. Depending on the outcome, 168 to 279 people were included for Chlorella and 101 to 299 for Spirulina. Trials lasted 4 to 16 weeks, with doses from 200 to 8000 mg a day.
What it can’t tell you
- The trials were small and used different doses, durations and populations, so the pooled results may hide differences between groups.
- Most people in the Chlorella trials already had normal blood pressure, so the results may not apply to those with high blood pressure.
- This review can only report on the outcomes that were measured in the included trials.
Who paid
- Funding
- Funded by Fundação para a Ciência e Tecnologia; Next Generation EU European Fund and the Portuguese Recovery and Resilience Plan (PRR) (from the PubMed record).
- Conflicts
- Authors Raquel Barros and Pedro A. Lima are employed by the company Sea4Us. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
- Authors work at
- University of Porto, Portugal; University of Aveiro, Portugal
The paper
- Title
- The Role of Chlorella and Spirulina as Adjuvants of Cardiovascular Risk Factor Control: A Systematic Review and Meta-Analysis of Randomised Controlled Trials
- Type
- Systematic review and meta-analysisThe authors follow a set, published method to find every relevant study, then combine the numbers from them into one result.
- Evidence
- Studies in people
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Pinto-Leite M, Martins D, Ferreira AC, et al (2025). The Role of Chlorella and Spirulina as Adjuvants of Cardiovascular Risk Factor Control: A Systematic Review and Meta-Analysis of Randomised Controlled Trials. Nutrients. doi:10.3390/nu17060943Free full textPubMed 40289965DOI
Summary written 29 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error