Can chlorella reduce inflammation? What the research does and doesn't show

The evidence doesn't line up in one direction. One trial in people with fatty liver disease found a commonly used inflammation marker, hs-CRP, was lower after 8 weeks of chlorella than placebo. A separate trial in healthy adults found some immune-related markers went up, not down, over the same length of time. No trial has tested chlorella against a diagnosed inflammatory or autoimmune condition at all.

What the evidence doesn't support

It doesn't support chlorella as a treatment for arthritis, an autoimmune condition, fibromyalgia, gout or chronic pain — none of those have been tested in a chlorella trial that we found. It doesn't support a single, consistent story about "chlorella and inflammation" either: the two relevant human trials measured different markers, in different populations, and moved in different directions. And it doesn't support chlorella replacing an anti-inflammatory medication for any condition; that comparison hasn't been tested.

What the trials found

An 8-week, placebo-controlled trial in 70 adults with fatty liver disease gave four 300 mg tablets of Chlorella vulgaris a day (1,200 mg/day total) or placebo. By the end of the trial, hs-CRP (a blood marker commonly used as a general sign of inflammation) and fasting blood glucose were both lower in the chlorella group, and the between-group difference in fasting glucose and in a second marker, TNF-alpha, was statistically significant. This was a trial in people with a specific liver condition, not a general population, and it measured blood markers, not a clinical inflammatory outcome like joint pain or swelling.

A different 8-week trial in 51 healthy adults, given 5 grams a day of chlorella tablets, found the opposite direction on some related markers: interferon-gamma and interleukin-1-beta, both involved in immune signaling, went up, not down, along with more active natural killer cells, versus placebo. That's a sign of increased immune activity in healthy people, not a reduction — a reminder that "affects the immune system" and "reduces inflammation" aren't automatically the same finding.

A third, smaller trial in people with borderline (undiagnosed) diabetes found lower activity of a gene called resistin after chlorella, and that change correlated with two other inflammation-related markers, TNF-alpha and IL-6, in the blood samples studied. The trial reported the gene-expression change and the correlation — it didn't report a direct, measured drop in TNF-alpha or IL-6 levels themselves.

Questions people ask

Can chlorella reduce inflammation?

One trial in people with fatty liver disease found lower hs-CRP with chlorella than placebo after 8 weeks. A different trial in healthy adults found some immune markers went up rather than down over the same length of time. There's no single, consistent answer across the human research we found.

Does chlorella help with joint pain or arthritis?

No trial we found tested chlorella against joint pain, arthritis or any other diagnosed inflammatory condition. The research that exists is about blood markers in people with fatty liver disease or in healthy adults, not joint symptoms.

When to talk to a doctor

Chlorella is not a treatment for an inflammatory or autoimmune condition, and a change in a blood marker in a small trial isn't the same as a diagnosed condition improving. If you have an autoimmune or inflammatory condition, or take medication for one, ask a doctor before adding chlorella — see chlorella and medications and chlorella side effects.