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Dietary supplement

Chlorella Ingredients & Drug Interactions

by Priority One Nutritional Supplements

Chlorella label
See full label image
Capsule Category: Other Combinations
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 23, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Chlorella against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Moderate

Chlorella is a dietary supplement by Priority One Nutritional Supplements with 1 active ingredient. Its ingredients are commonly taken for general nutrition and 'detox' support, immune support, liver and kidney support.Based on those ingredients, 337 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Chlorella. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Chlorella by Priority One Nutritional Supplements

Ask about any prescription or over-the-counter medication and we check it for interactions with Chlorella by Priority One Nutritional Supplements — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
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HelloPharmacist Scorecard of Chlorella by Priority One Nutritional Supplements

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 12, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This is a single-ingredient supplement: chlorella, a type of freshwater algae. It comes in a vegetarian capsule with rice chelate as an inactive ingredient.

The product contains no other active ingredients — just the chlorella itself.

Does it work?

Moderate evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed

This product doesn't appear to be marketed for a specific use, so we graded Chlorella's overall clinical evidence instead.

Moderate

Some clinical evidence supports Chlorella for:

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.
  • Since the label doesn't commit to one use, we graded the ingredient's overall clinical evidence instead.
  • On file: Pregnancy-related iron deficiency — rated "Possibly Effective" (Natural Medicines).

The evidence here is mixed and mostly thin. Chlorella is possibly effective for pregnancy-related iron deficiency, but for brain tumors, fatty liver disease, depression, and fatigue, we don't have enough reliable evidence to say whether it works.

If you're interested in it for one of those other reasons, talk to your doctor about what the research actually shows.

The evidence, ingredient by ingredient Chlorella

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Chlorella is generally well tolerated in the short term, but here's the catch: product quality and purity vary a lot, so you can't always count on what you're getting. Common side effects include allergic reactions, stomach cramping, constipation or diarrhea, nausea, gas, fatigue, and skin sensitivity to sun.

Most of these are mild and often settle down in the first two weeks. Rarely, severe allergic reactions like anaphylaxis have been reported.

Safety data overall is limited. Chlorella is rated possibly safe in pregnancy, but lactation safety isn't established.

If you're pregnant or nursing, the data isn't there to say yes or no, so talk with your doctor or pharmacist for personalized advice.

Side effects, ingredient by ingredient Chlorella

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Chlorella.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs.
  • For scale: 337 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Before taking this, double-check if you're on warfarin (Coumadin) — chlorella can make it less effective. Also flag any medications that cause photosensitivity or sun sensitivity, because chlorella may add to that effect.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with some supporting evidence behind its ingredients' uses. Moderate medication interactions have been identified, and safety information is well characterized.

Chlorella might be worth considering if you're dealing with pregnancy-related iron deficiency and your doctor is on board. But if you take warfarin or any photosensitizing medication, check with us first — those interactions are real.

Given the quality variation and limited long-term safety data, it's a supplement that deserves a conversation with your pharmacist before you start.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Oct 23, 2020.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Chlorella, straight from the product label.

Brand Priority One Nutritional Supplements
Barcode (UPC) 815354020389
Net contents 180 Vegetarian Capsule(s)
Market status On market
Date entered into DSLD Oct 23, 2020
DSLD ID 235703
Product type Other Combinations
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Vegetarian, Adult (18 - 50 Years)
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Chlorella by Priority One Nutritional Supplements, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Vegetarian Capsule(s)
Maximum serving Sizes:
1 Vegetarian Capsule(s)
UPC/BARCODE
815354020389
IngredientAmount% DV
Chlorella300 mg--

Other ingredients: Rice Chelate, Vegetarian Capsule

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Precautions

Warning: If you are pregnant or breast feeding, consult your physician before using this product.

Keep out of reach of children.

Suggested/Recommended/Usage/Directions

Recommendations: Adults take one (1) capsule daily or as directed by your physician.

Storage

Keep container tightly closed, store in a cool, dry place.

Formulation

Contains no preservatives.

Vegetarian formulation

Non-GMO

General Statements

Bisphenol-A (BPA) & Phthalate Free

Priority One Nutritional Supplements Inc since 1988

For professional use only.

Seals/Symbols

GMP Certified

FDA Statement of Identity

A Dietary Supplement

FDA Disclaimer Statement

This statement has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Chlorella by Priority One Nutritional Supplements label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Chlorella label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Chlorella by Priority One Nutritional Supplements

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size1 Vegetarian Capsule(s) Dosage formCapsule Amounts shown are per serving.

Chlorella

Interacts with
337 drugs
300 mg per serving

Chlorella is a nutrient-rich freshwater green algae taken as a supplement for general wellness, immune support, and 'detox.' Some small studies sugges...

Chlorella monograph & interactions

Other (inactive) ingredients: Rice Chelate, Vegetarian Capsule. These complete the product’s ingredient list but are not active constituents.

Interaction report

Chlorella by Priority One Nutritional Supplements Drug Interactions

Want to check YOUR meds against Chlorella?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
337Drugs
337 Moderate

Ingredients driving the most interactions

Chlorella 337

Individual Drug Interactions

The ingredients in Chlorella interact with 337 drugs. Click any drug to see the details.

1 of the 1 ingredient in Chlorella interact with drugs. Each result below shows which ingredient is responsible. Chlorella

Each ingredient & the kinds of drugs it affects

For each ingredient in Chlorella with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

Chlorella2 drug types · 337 drugs

Photosensitizing Drugs

Theoretically, chlorella might have additive effects with photosensitizing drugs.
Chlorella has been reported to cause photosensitization. In five case reports, patients who had ingested chlorella exhibited swelling followed by erythematopurpuric lesions on sun-exposed areas of the body. Theoretically, concomitant use with photosensitizing drugs may exacerbate effects.

Likelihood Possible Evidence D
Warfarin (Coumadin)

Theoretically, chlorella might reduce the clinical effects of warfarin.
Chlorella contains significant amounts of vitamin K. There is at least one case report of warfarin therapy becoming sub-therapeutic after initiation of chlorella supplements.

Likelihood Possible Evidence D
Chlorella full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Chlorella, from the product label.

Priority One Nutritional Supplements

See all Priority One Nutritional Supplements products
Name
Priority One Nutritional Supplements, Inc.
Pharmacist Counseling Corner

Chlorella by Priority One Nutritional Supplements: Common Questions

Does Chlorella by Priority One Nutritional Supplements interact with any medications?
Yes. Based on its ingredients, Chlorella has a known interaction with 337 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Chlorella contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Is this safe to take long-term?
We don't have enough safety data to say it's safe for the long haul. Short-term use is generally well tolerated, but quality and purity vary widely across products. Talk to your doctor if you're thinking about taking it regularly.
What are the most common side effects?
Stomach issues like cramping, diarrhea, constipation, nausea, and gas show up most often, especially in the first two weeks. You might also notice allergic reactions, fatigue, or skin sensitivity to sun. Most people find these settle down pretty quickly.
Can I take this if I'm pregnant?
Chlorella is rated possibly safe in pregnancy, but we don't have enough data to know for certain. Lactation safety isn't established either. Talk with your doctor or us before starting — it's a personal call based on your situation.
Does chlorella actually work for anything?
The only thing we have decent evidence for is pregnancy-related iron deficiency, where it's possibly effective. For brain tumors, fatty liver disease, depression, and fatigue, the research just isn't there yet. Your doctor can point you to the latest studies if you're curious about a specific use.
Why does it say I need to check my blood thinner medication?
Chlorella has a lot of vitamin K, which blocks how warfarin (and similar blood thinners) work. There's a real case report of someone's warfarin failing because of chlorella. If you're on a blood thinner, we need to make sure this won't mess with it.
What's the allergic reaction risk?
Most allergic reactions are mild, but serious ones like asthma and even anaphylaxis have been reported — though they're rare. If you have a history of algae or seafood allergies, mention that when you talk to us.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Not sure if Chlorella is safe with your meds?

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Chlorella label
Go deeper

The Full Monographs Behind Chlorella’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Chlorella

Interacts with 337 drugs

Chlorella is a nutrient-rich freshwater green algae taken as a supplement for general wellness, immune support, and 'detox.' Some small studies suggest possible benefits for cholesterol, blo...

Read the full Chlorella monograph →
Sources

Sources & How We Checked

Chlorella's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 13 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Chlorella 13 references
  1. Peirce A. The American Pharmaceutical Association Practical Guide to Natural Medicines. New York, NY: William Morrow and Co., 1999.
  2. Ng TP, Tan WC, Lee YK. Occupational asthma in a pharmacist induced by chlorella, a unicellular algae preparation. Resp Med 1994;88:555-7. PubMed
  3. Jitsukawa K, Suizu R, Hidano A. Chlorella photosensitization. New phytophotodermatosis. Int J Dermatol 1984;23:263-8. PubMed
  4. Merchant RE, Carmack CA, Wise CM. Nutritional supplementation with Chlorella pyrenoidosa for patients with fibromyalgia syndrome: a pilot study. Phytother Res 2000;14:167-73.
  5. Merchant RE, Rice CD, Young HF. Dietary Chlorella pyrenoidosa for patients with malignant glioma: effects on immunocompetence, quality of life, and survival. Phytother Res 1990;4:220-31.
  6. Halperin SA, Smith B, Nolan C, et al. Safety and immunoenhancing effect of a Chlorella-derived dietary supplement in healthy adults undergoing influenza vaccination: randomized, double-blind, placebo-controlled trial. CMAJ 2003;169:111-7..
  7. Ohtake, T., Negishi, K., Okamoto, K., Oka, M., Maesato, K., Moriya, H., and Kobayashi, S. Manganese-induced Parkinsonism in a patient undergoing maintenance hemodialysis. Am J Kidney Dis 2005;46(4):749-753. PubMed
  8. Ng, T. P., Tan, W. C., and Lee, Y. K. Occupational asthma in a pharmacist induced by Chlorella, a unicellular algae preparation. Respir.Med. 1994;88(7):555-557. PubMed
  9. Ohkawa, S., Yoneda, Y., Ohsumi, Y., and Tabuchi, M. [Warfarin therapy and chlorella]. Rinsho Shinkeigaku 1995;35(7):806-807.
  10. Azocar J, Diaz A. Efficacy and safety of chlorella supplementation in adults with chronic hepatitis C virus infection. World J Gastroenterol 2013;19(7):1085-90. PubMed
  11. Panahi Y, Badeli R, Karami GR, Badeli Z, Sahebkar A. A randomized controlled trial of 6-week Chlorella vulgaris supplementation in patients with major depressive disorder. Complement Ther Med 2015;23(4):598-602. PubMed
  12. Nakano S, Takekoshi H, Nakano M. Chlorella pyrenoidosa supplementation reduces the risk of anemia, proteinuria and edema in pregnant women. Plant Foods Hum Nutr 2010;65(1):25-30. PubMed
  13. Yavasoglu I, Turgutkaya A, Bolaman Z. Chlorella-induced thrombocytopenia. Sao Paulo Med J 2018;136(6):602-3. PubMed

See these in context on the Chlorella monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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