Chlorella

Chlorella vulgaris · Chlorella pyrenoidosa · Green Algae

Snapshot

Indications	Contraindications
Total and LDL cholesterol^{1, 2} Blood pressure² Fasting glucose² Fatty liver enzymes^{3, 4} Iron status⁵ Fibromyalgia pain⁶	Hypersensitivity to chlorella⁷ Pregnancy or breastfeeding⁷

Chlorella is a single-celled green freshwater alga sold as a dietary supplement, supplying vitamin B12, folate, and iron alongside antioxidant and immunomodulatory activity⁸. People take it as a nutrient-dense whole food and for cardiometabolic risk factors, including cholesterol, blood pressure, and fasting glucose². Further uses are non-alcoholic fatty liver disease (NAFLD), iron status, and fibromyalgia pain.

A 2026 meta-analysis in NAFLD reported improved liver enzymes and glycemic control, with very low certainty and all trials from Iran³. In 2025, a laboratory analysis of commercial spirulina and chlorella supplements found toxic metals within European Union limits but detected pharmaceutical residues, and no trial has tested what that exposure means clinically. More than 3,000 products list chlorella, mostly tablets and powders with some capsules and liquids; see Form comparison.

Health Canada lists hypersensitivity as a known adverse reaction on licensed products and directs patients to stop use if it occurs⁷. Health Canada labels also ask for a practitioner's advice before use alongside blood thinners⁷.

Last updated October 15, 2026. Read how we make monographs.

In the full monograph

70 sources, 54 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources