Chlorella: benefits, dosage, side-effects

Find out all about chlorella, including what it does, the benefits to taking it and how much you might need


What is chlorella and what does it do?

Chlorella is a tiny green algae that grows in freshwater ponds and lakes in south east Asia and Australia.1 The name comes from the Greek word for ‘green’, a reference to its vivid colour. Chlorella is also highly nutritious. It’s a source of:2,3,    In fact, it could be considered the first superfood: in the 1940s, scientists investigated whether chlorella could become a cheap, nutritious source of protein in times of scarcity, although it proved too expensive to grow in bulk.4

Traditionally used as a food supplement in Japan, studies have found various health benefits from taking chlorella, including:

  • reduced cholesterol levels and improved fat metabolism5
  • immune system support6
  • a detoxifying effect, removing heavy metals from the body7

It’s available as a powder, capsules or tablets.

Benefits of chlorella

What does chlorella do in the body?

It’s thought that chlorella has a few key jobs:

1. Improved cholesterol and fat metabolism

Chlorella may help lower cholesterol levels and improve fat metabolism in people with raised blood cholesterol, according to a 2014 study from Korea. Chlorella is a likely source of fat-soluble carotenoids – orange, yellow and red plant pigments – and scientists think these compete with fats for transportation in the blood, reducing the amount of fat in cells.8

2. Immune support

Scientists think chlorella has a stimulatory effect on the immune system. A Korean study published in 2012 in Nutrition Journal found that when healthy adults were given 5g of chlorella a day for eight weeks, their bodies increased levels of immune cells known to fight bacteria.9

3. Toxin removal

Chlorella may have a detoxifying effect, binding with heavy metals – like copper, lead and cadmium – which are then flushed out of the body as waste, although human studies are needed to confirm its effects.10 It’s not usual to be exposed to heavy metals but pollution or certain jobs, like mining, can increase this possibility.

 4. Reduced blood sugar levels

A 2008 Japanese study on 17 healthy people with high-risk factors for lifestyle-related disease reported that chlorella helped reduce blood sugar.11


How much chlorella is safe to take?

There are no dietary recommendations for taking chlorella, but some studies use 1.2g a day, and others 5-10g daily.12 If you want to take chlorella, read the label carefully and avoid taking more than advised.

Do not take chlorella if you:

  • are pregnant – it has not been proven safe during pregnancy
  • have an immune deficiency disorder – chlorella has been shown to stimulate the immune system13
  • are taking the anticoagulant medicine warfarin – chlorella is a source of vitamin K, which is important for blood-clotting14
Chlorella is freshwater algae, which are low in iodine, unlike marine algae. This means you don’t need to worry about consuming too much idodine.15

If you’re interested in taking chlorella, talk to your GP or an experienced medical herbalist first.


What are the side-effects of taking chlorella?

The following side-effects have been reported from taking chlorella:16
  • nausea
  • stomach discomfort
Shop Superfood Supplements Advice is for information only and should not replace medical care. Please check with your GP before trying any remedies. Written by Carole Beck on December 6, 2018 Reviewed by Azmina Govindji on December 11, 2018

1. Victoria Lambert. The Telegraph. Chlorella: the superfood that helps fight disease. Available from:
2. Keri-Ann Jennings. Healthline. 9 Impressive Health Benefit of Chlorella. Available from:
3. Ryu NH, et al. Impact of daily Chlorella consumption on serum lipid and carotenoid profiles in mildly hypercholesterolemic adults: a double-blinded, randomized, placebo-controlled study. Available from:
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6. Kwak JH, et al. Beneficial immunostimulatory effect of short-term Chlorella supplementation: enhancement of Natural Killer cell activity and early inflammatory response (Randomized, double-blinded, placebo-controlled trial). Available from:
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16. Halperin S, et al. Safety and immunoenhancing effect of a Chlorella-derived dietary supplement in healthy adults undergoing influenza vaccination: randomized, double-blind, placebo-controlled trial. Available from: