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Chlorella is a single-celled green alga that grows in fresh water, and it is sold as a powder or tablets. This guide covers what we know about its safety, why the broken cell wall matters on a label, how to read a chlorella product, and how five organic chlorella powders compare by size and certification.General information, not medical advice. Talk to your doctor or pharmacist before you start a supplement, especially if you are pregnant, take medicine or are buying for a child.
Key Specs Compared
Numbers match the reviews below (tap to jump).
| # | Form | Size | Stated certifications | Gluten-free |
|---|---|---|---|---|
| 1 | Powder | 10 Ounce | USDA Organic, Non-GMO, Gluten-free | Yes |
| 2 | Powder | 8 Ounce | USDA Organic, Non-GMO | Yes |
| 3 | Powder | 8 Ounce | USDA Organic, Non-GMO | Yes |
| 4 | Powder | 7.94 Ounce | USDA Organic, EU Organic, Naturland | Yes |
| 5 | Powder | 6 Ounce | Certified organic, Non-GMO, Kosher | Yes |
– = not stated on the Amazon listing · Specs and certifications as stated by the listing, not tested or verified by us; check the listing before you buy
Chlorella safety
- Allergic reactions, including asthma and anaphylaxis, have been reported in people taking chlorella and in people preparing chlorella tablets.[1]
- Chlorella is high in vitamin K, which may reduce how well warfarin works. Talk to your provider before you start it if you take warfarin.[1]
- Chlorella can cause nausea, diarrhea, abdominal cramping, gas and green stools, and some people become more sensitive to sunlight.[1]
- There is no compelling research that detox diets or products remove toxins from the body.[2]
What Is Chlorella?
- The Alga – Chlorella is a fresh-water green alga that contains carotenes, protein, fiber, vitamins, minerals and chlorophyll.[1]
- Chlorella and Spirulina – They are often sold side by side, but chlorella is a green alga and spirulina is a different organism, a cyanobacterium.
- Supplements – Chlorella is sold as a dietary supplement, and the FDA does not approve supplements before they are sold.[3]
- Detox Claims – Chlorella is often sold as a detox product. A 2015 review found no compelling research that detox diets eliminate toxins from the body.[2]
Safety and Side Effects
- Digestive Effects – The most common effects are nausea, diarrhea, cramping, gas and green stools.[1]
- Allergies – Stop taking chlorella and get medical help right away if you have trouble breathing, swelling, hives or fainting.[1]
- Sun Sensitivity – Photosensitivity reactions have occurred after taking chlorella, so use sun protection.[1]
- Warfarin – The high vitamin K content of chlorella may decrease warfarin effectiveness.[1]
- Pregnancy and Breastfeeding – LactMed says chlorella taken while breastfeeding is probably acceptable, and green breast milk has been reported. Ask your provider first.[1]
What to Check on a Chlorella Label
- Cell Wall – Chlorella has a tough cell wall. Products sold as broken or cracked cell wall, such as Micro Ingredients, Anthony’s and Terrasoul, have been processed to break it.
- Serving Size – The supplement facts panel gives the serving. Nutricost states 3 grams per serving, and Micro Ingredients states up to 76 servings in a 10 oz bag.[3]
- Organic Seal – Look for the USDA Organic seal if you want a certified organic product.[4] Triquetra Health also states EU Organic and Naturland certification.
- Testing – Look for third-party testing for purity. Several of these brands state it.
- Count and Price – Divide the price by the number of servings to compare powders fairly.
What the Research Says
LactMed describes chlorella as usually well tolerated, with nausea, diarrhea, abdominal cramping and flatulence as side effects, and it notes reports of allergic reactions, photosensitivity and a warfarin interaction.[1] NCCIH says a 2015 review found no compelling research to support detox diets for eliminating toxins from the body, and that FDA and the Federal Trade Commission have acted against detox products with hidden ingredients or false claims.[2]How We Chose These Products
We do not test products. We compare product details: form, amount per container, stated certifications, ingredients and availability.[3][4] Brands don’t pay to be included, though we may earn a commission from purchases.Our Organic Chlorella Picks
These five organic chlorella powders range from 6 oz to 10 oz, each with a USDA Organic claim. With every purchase through the links on this page, we may earn a commission, at no extra cost to you.1
Micro Ingredients® Organic Chlorella Powder Raw organic chlorella powder, broken cell wall, 10 oz
- Micro Ingredients Organic Chlorella is a 10 oz bag of raw, broken-cell-wall chlorella powder, with up to 76 servings.
- It is USDA Organic, non-GMO and gluten-free, with no additives, fillers or flavors, and each lot goes through third-party lab tests.
- It is the largest bag of the five.
2
Anthony's® Organic Chlorella Powder Organic chlorella powder, broken cell wall, 8 oz
- Anthony’s Organic Chlorella is an 8 oz bag of broken-cell-wall powder.
- It is USDA Organic, non-GMO and vegan, and each batch is tested to verify gluten-free.
- Stir it into smoothies and juices, or sprinkle it on food.
3
Nutricost® Organic Chlorella Powder Organic chlorella powder with scoop, 3 g per serving, 8 oz
- Nutricost Organic Chlorella is an 8 oz bottle with a serving scoop that measures 3 grams.
- It is USDA Organic, non-GMO, gluten-free and vegetarian.
- It is made in a GMP-compliant, FDA-registered facility.
4
Triquetra Health® Organic Chlorella Powder Raw sun-grown organic chlorella powder, 75 servings, 225 g
- Triquetra Health Organic Chlorella is a 225 g (7.94 oz) tub of raw, broken-cell-wall powder with 75 servings.
- It states USDA Organic, EU Organic and Naturland certification, the most certifications of the five.
- The chlorella is sun-grown in South India and third-party tested, and it is never heat-treated or irradiated.
5
Terrasoul Superfoods® Organic Chlorella Powder Organic chlorella powder with cracked cell walls, 6 oz
- Terrasoul Superfoods Organic Chlorella is a 6 oz bag of cracked-cell-wall powder.
- It is certified organic, non-GMO, Earth Kosher, raw, gluten-free and vegan.
- It is the smallest bag of the five, which suits a first try.
Index Table: Organic Chlorella Powder
| No. | Product | Image | Features | Brand |
|---|---|---|---|---|
| 1 | Micro Ingredients Organic Chlorella Powder - Raw organic chlorella powder, broken cell wall, 10 oz |  |
| Micro Ingredients |
| 2 | Anthony's Organic Chlorella Powder - Organic chlorella powder, broken cell wall, 8 oz |  |
| Anthony's |
| 3 | Nutricost Organic Chlorella Powder - Organic chlorella powder with scoop, 3 g per serving, 8 oz |  |
| Nutricost |
| 4 | Triquetra Health Organic Chlorella Powder - Raw sun-grown organic chlorella powder, 75 servings, 225 g |  |
| Triquetra Health |
| 5 | Terrasoul Superfoods Organic Chlorella Powder - Organic chlorella powder with cracked cell walls, 6 oz |  |
| Terrasoul Superfoods |
Sources
- National Library of Medicine. Chlorella. Drugs and Lactation Database (LactMed). Accessed October 27, 2026.
- National Center for Complementary and Integrative Health. “Detoxes” and “Cleanses”: What You Need To Know. Accessed October 27, 2026.
- NIH Office of Dietary Supplements. Dietary Supplements: What You Need to Know. Accessed October 27, 2026.
- USDA Agricultural Marketing Service. Organic Labeling Standards. Accessed October 27, 2026.
Update History
- Oct 2026: Rewrote the guide text and product notes around the LactMed chlorella entry and the NCCIH detox page, added the allergy, warfarin, sun sensitivity and cell wall guidance, removed unsupported claims, and replaced the sources (National Library of Medicine, NCCIH, NIH, USDA)
- Jul 2021: First published
